JP3748245B2 - MPEG data recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, the first and second MPEG image data, which are image data encoded by the MPEG encoding method, are converted into the first MPEG image at specified connection specification positions in the respective MPEG image data. The present invention relates to an MPEG data recording apparatus for realizing seamless reproduction when data is connected to the second MPEG image data for reproduction.
[0002]
[Prior art]
The conventional MPEG used in this patent will be briefly described.
[0003]
Since MPEG is described in detail in ISO-IEC11172-2 and ITU-T H.262 / ISO-IEC13818-2, only the outline will be described here. MPEG is the name of the organization that examines video coding standards established in 1988 in ISO / IEC JTC1 / SC2 (International Organization for Standardization / International Electrotechnical Standards Meeting Technical Committee 1 / Technical Committee 2, now SC29) ( Abbreviation for Moving Pictures Expert Group. MPEG1 (MPEG Phase 1) is a standard for storage media of about 1.5 Mbps, and is intended for video compression for low transfer rates of JPEG and ISDN video conferences and videophones for the purpose of still image coding. H.261 (CCITT SGXV, standardized by the current ITU-T SG15), the new technology was introduced for storage media. These were established in August 1993 as ISO / IEC 11172.
[0004]
MPEG1 is created by combining several technologies. FIG. 5 shows a conventional MPEG encoder that performs encoding by the MPEG encoding method, which will be briefly described below. For the input image, the difference between the image decoded by the motion compensation predictor 1 and the input image is taken by the differencer 2 to reduce the time redundant portion.
[0005]
There are three modes of prediction from the past and the future. These can be used by switching every 16 pixels × 16 pixels MB (Macroblock). The prediction direction is determined by the picture type given to the input image. One-way inter-picture predictive coded images (P-pictures) exist in two modes: a mode in which encoding is performed by prediction from the past and a mode in which MB is independently encoded without prediction. In addition, there are four modes of bi-directional inter-picture prediction: a mode that encodes by prediction from the future, a mode that encodes by prediction from the past, a mode that encodes by prediction from both, and a mode that encodes independently. This is a B-picture. All MBs are independently encoded in an intra-picture independently encoded image (I-picture).
[0006]
In motion compensation, the motion region is subjected to pattern matching for each MB, a motion vector is detected with half-pel accuracy, and prediction is performed after shifting by the motion amount. The motion vector has a horizontal direction and a vertical direction, and is transmitted as additional information of the MB together with an MC (Motion Compensation) mode indicating where the motion vector is predicted.
[0007]
Generally, the GOP (Group Of Picture) is a group of pictures from the I picture to the picture before the next I picture. When used in storage media, etc., about 15 pictures are generally used as one GOP section. Is done. (However, two or more I pictures may be included in one GOP section. In short, one or more I pictures may be included in one GOP section.)
The difference image is subjected to orthogonal transformation in the DCT unit 3. DCT (Discrete Cosine Transform) is an orthogonal transformation that discretely transforms an integral transformation with a cosine function as an integral kernel into a finite space. In MPEG, MB is divided into four and two-dimensional DCT is performed on an 8 × 8 DCT block. In general, video signals have many low-frequency components and few high-frequency components. Therefore, when DCT is performed, coefficients are concentrated in the low frequency range.
[0008]
The image data (DCT coefficient) subjected to DCT is quantized by the quantizer 4. Quantization is a quantized value obtained by multiplying the 8 × 8 two-dimensional frequency called the quantization matrix by the visual characteristic weighted by the value of the quantization scale that multiplies the whole by a scalar, and the DCT coefficient is quantized. Calculate by value. When inverse quantization is performed by the MPEG decoder (decoder), a value approximating the original DCT coefficient is obtained by multiplying by the quantized value.
[0009]
The quantized data is variable length encoded by the VLC unit 5. Among the quantized values, the direct current (DC) component uses DPCM (differential pulse code modulation) which is one of predictive coding. Also, AC (AC) components are zigzag scanned from low to high, with zero run length and effective coefficient value as one event, and Huffman coding assigning codes with short code lengths from those with high appearance probability. Is done.
[0010]
The variable-length encoded data is stored in the temporary buffer 6 and output as encoded data at a predetermined transfer rate. The generated code amount for each macroblock of the output data is transmitted to the code amount controller 21, and the error code amount with respect to the generated code amount with respect to the target code amount is fed back to the quantizer 4 to quantize the scale. The amount of code is controlled by adjusting.
[0011]
The quantized image data is inversely quantized by the inverse quantizer 7, inversely DCTed by the inverse DCT unit 8, temporarily stored in the image memory 10 via the adder 9, and then the motion compensated predictor 1. Are used as reference decoded images for calculating difference images.
[0012]
FIG. 6 shows an MPEG decoder (decoder) for decoding the encoded data encoded in this way.
[0013]
Incoming encoded data (stream) is buffered by the buffer 11, and the data from the buffer 11 is input to the VLD unit 12. The VLD unit 12 performs variable length decoding to obtain a direct current (DC) component and an alternating current (AC) component. The alternating current (AC) component data is arranged in an 8 × 8 matrix in the order of zigzag scan from low to high. This data is input to the inverse quantizer 13 and is inversely quantized by the quantization matrix. The inversely quantized data is input to the inverse DCT unit 14 and subjected to inverse DCT, and output as image data (decoded data). The decoded data is temporarily stored in the image memory 16 and then used as a reference decoded image for calculating a difference image in the motion compensation predictor 17.
[0014]
In the case of video, the encoded bit stream has a variable amount of code for each picture. This is because MPEG uses information conversion such as DCT, quantization, and Huffman coding, and at the same time, it is necessary to adaptively change the amount of code allocated to each picture to improve image quality. This is because the entropy of the encoded image itself changes greatly, such as encoding the input image as it is in some cases and encoding a difference image that is the difference between the predicted images in some cases.
[0015]
In this case, in many cases, the code amount is controlled while allocating the entropy ratio of the image and keeping the limitation of the buffer. The buffer manager monitors the relationship between the generated code amount and the encoding rate, and sets the target code amount so as to be within a predetermined buffer. This value is fed back to the variable length encoder and enters the code amount controller, where the generated code amount is suppressed by increasing the quantized value set in the quantizer or by reducing the quantized value. Or make it smaller.
[0016]
When encoding such variable-length data at a fixed transfer rate (encoding rate), if the maximum buffer amount of the decoder is the upper limit value, the data is input at a constant speed and only a predetermined value is accumulated. Therefore, MPEG is specified to use a model that performs decoding instantaneously at a predetermined time (1 / 29.97 sec unit for NTSC video signals) and encodes the buffer so that neither overflow nor underflow occurs. ing. If this rule (VBV buffer rule) is observed, the rate in the VBV buffer changes locally, but if the observation time is long, it becomes a fixed transfer rate. In MPEG, this is a fixed rate. Defined.
[0017]
In the case of a fixed transfer rate, when the amount of generated code is small, the buffer occupation amount is stuck to the upper limit value. In this case, it is necessary to increase the code amount so as not to overflow by adding an invalid bit.
[0018]
In the case of variable transfer rate, the definition of this fixed transfer rate is expanded so that when the buffer occupancy reaches the upper limit value, it is defined so that overflow will not occur in principle by stopping reading of the decoder. ing. Such a buffer transition is shown in FIG. Even if the amount of generated code is very small, reading of the decoder is stopped, so there is no need to insert invalid bits as in the case of a fixed transfer rate. Therefore, encoding is performed so that only underflow does not occur.
[0019]
The MPEG system stipulates a method for reproducing a bit stream that is encoded with MPEG video and audio, etc., and multiplexed into one bit stream while ensuring synchronization. The contents specified in the system are roughly divided into the following five points.
1) Synchronous playback of multiple encoded bitstreams 2) Multiplexing of multiple encoded bitstreams into a single bitstream 3) Buffer initialization at playback start 4) Continuous buffer management 5) Determining the time for decoding and playback
In order to multiplex in the MPEG system, it is necessary to packetize information. Packet multiplexing means, for example, when video and audio are multiplexed, each is divided into streams of appropriate length called packets, attached with additional information such as headers, and video and audio packets are switched appropriately. Time-division transmission. The header includes information for identifying video, audio, etc., and time information for synchronization. The packet length depends on the transmission medium and application, and ranges from 53 bytes like ATM to as long as 4 Kbytes like optical disc. In MPEG, the packet length is variable and can be specified arbitrarily.
[0020]
Data is packed and packetized, and one pack is composed of several packets. Pack start code and SCR (System Clock Referance) are described in the head part of each P pack, and stream id and time stamp are described in the head part of the packet. The time stamp describes time information for synchronizing audio, video, etc., and there are two types, DTS (Decoding Time Stamp) and PTS (Presentation Time Stamp). PCR (Program Clock Reference) is described with a time accuracy of 27 MHz, and is information for locking the reference clock of the decoder. DTS indicates the decoding start time of the first access unit (1 picture for video, 1152 samples for audio) in the packet data, and PTS indicates the display (playback) start time. As shown in FIG. 11, the audio, video, and other decoders constantly monitor a common reference clock locked by PCR, and perform decoding and display when they coincide with the DTS or PTS time. . Multiplexed data is buffered by each decoder, and a virtual decoder for synchronized display is called STD (System Target Decoder), and multiplexed so that this STD does not cause overflow or underflow. Must be.
[0021]
The MPEG system is roughly divided into TS (Transport Stream) and PS (Program Stream). These are composed of packets including PES (Packetized Elementary Stream) and other necessary information. PES is defined as an intermediate stream for enabling conversion between both streams, and is a packet of a private stream or the like in addition to video and audio data encoded with MPEG.
[0022]
PS can multiplex video and audio of programs with a common reference time. The packet layer is called PES, and this structure is used in common with a TS, which will be described later, as shown in FIG. In the PS STD model, streams are switched by the stream id in the PES packet.
[0023]
TS can also multiplex video and audio of programs that have a common reference time like PS, but TS can also multiplex multi-programs such as communications and broadcasts that have different reference times It is said. The TS is composed of a 188-byte fixed-length packet in consideration of the ATM cell length and error correction coding, and is considered so that it can be used even in a system in which an error exists. Although the structure of TS packet itself is not so complicated, its operation is complicated because it is a multi-program stream. A characteristic of PS is that although TS packets have a higher structure, they are (usually) shorter than PES packets, and are divided into TS packets for transmission. In the STD model of TS, the stream is switched by the PID (packet ID) in the TS packet.
[0024]
The MPEG system TS has a mechanism for indicating which PID is a packet related to information of the multiplexed program. This will be described with reference to FIG. First, search for TS packets with PID = 0. It is an information packet called PAT (Program Association Table), in which information PID corresponding to the PROGRAM number PR is described in a linked form. Next, when reading the PID packet corresponding to the target PR, there is an information packet called PMT (Program Map Table). Among these packets, the PID of the video packet of the program corresponding to the PR and the audio packet are included. PID information is described.
[0025]
PAT and PMT are called PSI (Program Specific Information), which is an information system that allows access (entry) to the channel of the target program.
[0026]
Conventionally, according to the invention of Japanese Patent Laid-Open No. 11-74799, when editing compressed data such as MPEG data recorded on a recording medium, the VBV buffer is always fixed at the editing point in order to maintain the continuity of the MPEG data. There are described methods for performing coding in consideration of continuity, such as controlling the amount of generated code so that the GOP becomes equal, or coding the GOP as a closed GOP.
[0027]
Further, according to the invention of Japanese Patent Laid-Open No. 11-187354, there is no restriction on the encoded data, and the information indicating the data extracted as the editing material in the partial section of the data and the reproduction order thereof. A method is described in which information can be described and video editing can be realized on a single recording medium without changing the recorded data.
[0028]
[Problems to be solved by the invention]
However, in the conventional method described above, when MPEG image data is simply connected, a contradiction occurs in the connection of the VBV buffer, and overflow and underflow occur.
[0029]
In the invention of Japanese Patent Laid-Open No. 11-74799, the generated code amount is controlled so that the VBV buffer is always fixed for each GOP so that it can be edited anywhere, the GOP is encoded as a closed GOP, etc. Encoding restrictions considering continuity are imposed, which is a disadvantageous factor in encoding efficiency.
[0030]
In the invention disclosed in Japanese Patent Laid-Open No. 11-187354, playback is displayed as if it had been edited, but the continuity at the editing point is incomplete, and temporary rest such as initialization of the decoder buffer of MPEG data is performed. There was a possibility that the phenomenon occurred.
[0031]
The present invention provides first and second MPEG image data (or packet-multiplexed first MPEG multiplexed data including the first MPEG image data as element encoded data) and second MPEG Packet-multiplexed second MPEG multiplexed data including image data as element-coded data), and the second MPEG image data from the first MPEG image data at each designated connection designation position. When connecting to a VBV buffer (when reproducing from the first MPEG multiplexed data to the second MPEG multiplexed data), there is no inconsistency in overflow or underflow in the connection of the VBV buffer. An object of the present invention is to provide an MPEG data recording apparatus capable of realizing seamless and high-quality playback.
[0032]
[Means for Solving the Problems]
Therefore, in order to solve the above problems, the present invention provides the following recording apparatus.
(1) The first and second MPEG image data, which are image data encoded by the MPEG encoding method and recorded on the same recording medium , are connected at specified connection specification positions in the respective MPEG image data. , Generating and recording the third linked section re-encoded data encoded by the MPEG encoding method as the data to be reproduced from the first MPEG image data to the second MPEG image data. An MPEG data recording apparatus provided with recording means for
The recording means includes
A section having a start position in the first MPEG image data as a start position and a end position at the connection specified position in the first MPEG image data is a first connection. A section having a connection designated position in the second MPEG image data as a start position and a position after a second predetermined time from the connection designated position in the second MPEG image data as an end position. As a second connecting section, and a section combining the first connecting section and the second connecting section as a third connecting section,
Decoding the first joint section decoded image data, which is image data obtained by decoding the first MPEG image data in the first joint section, and the second MPEG image data in the second joint section. The third joint section decoded image data composed of the second joint section decoded image data, which is the image data obtained as described above, is re-encoded by the MPEG encoding method, and the third joint section re-encoded data is obtained. Re-encoding means for generating , and recording the third linked section re-encoded data in an area different from each area where the first and second MPEG image data are recorded on the same recording medium. It is what
In the re-encoding, the re-encoding means encodes the first MPEG image data at a position where the transition of the information value related to the VBV buffer occupation value corresponds to the start position of the first connection section. Starting from the information value related to the VBV buffer occupancy value, and ends up to the information value related to the VBV buffer occupancy value at the time of encoding the second MPEG image data at the position corresponding to the end position of the second connection interval. The code amount is controlled as described above and re-encoding is performed.
MPEG data recording apparatus characterized by the above.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
First, the concept of joint reproduction that can be realized by the present invention will be described. As shown in FIG. 8, when the second MPEG image data exists in the same way as the first MPEG image data which is the image data encoded by the first MPEG encoding method, the middle of the first MPEG image data (specified Consider that the second MPEG image data is connected and reproduced from the connection designated position). Assuming that the connection point (connection designation position in the first MPEG image data) is the position b, the reproduction is performed up to the position b in the first MPEG image data, and then the data is connected to the second MPEG image data. However, when MPEG image data are simply connected, there is a problem in that the connection of the VBV buffer is inconsistent and overflow or underflow occurs.
[0034]
Therefore, first, the information of the VBV buffer at the time of encoding the first MPEG image data and the second MPEG image data by the MPEG encoding method is set to a predetermined section unit (the first predetermined image in the first MPEG image data). It is generated as side information in a section unit, and in the second MPEG image data, a second predetermined section unit) and is described in the recording medium.
[0035]
Note that it is also possible to realize splicing reproduction without describing the information of the VBV buffer in this side information. In this case, two methods can be considered, which will be described later.
[0036]
The VBV buffer information related to the first MPEG image data is related to the VBV buffer occupancy value at the MPEG encoding start time or end time of the last picture in the first MPEG image data for each first predetermined interval. First VBV buffer occupancy value related information indicating an information value, and first address information indicating at which position in the first MPEG image data the information value related to the VBV buffer occupancy value is an information value related to the VBV buffer occupancy value It is.
[0037]
The VBV buffer information related to the second MPEG image data relates to the VBV buffer occupancy value at the MPEG encoding start time or end time of the last picture in the second MPEG image data for each second predetermined interval. Second VBV buffer occupancy value related information indicating an information value, and a second address indicating where the information value related to the VBV buffer occupancy value is an information value related to the VBV buffer occupancy value in the second MPEG image data Information.
[0038]
The information value related to the VBV buffer occupation value is, for example, a VBV buffer occupation value or a VBV delay value defined by MPEG.
[0039]
As described later, one unit of the first and second predetermined sections may be about 3 frames or about 1 GOP. The predetermined interval unit is assumed to be between ab in FIG. 8 for the first MPEG image data and between cd in FIG. 8 for the second MPEG image data.
[0040]
In the information list of the VBV buffer, the position of a (the boundary of the first predetermined section before the first predetermined time from the connection specified position in the first MPEG image data: that is, the start of section A described later) The VBV buffer information at the position (position) and the VBV buffer information at the position b (the connection designation position in the first MPEG image data: that is, the end position of the section A described later) are described. Also, the information of the VBV buffer at the position c of the second MPEG image data (the boundary position of the second predetermined section a second predetermined time before the connection specified position in the second MPEG image data) Also, there is information on the VBV buffer at the position of the connection point d (the connection designation position in the second MPEG image data: the boundary position of the second predetermined section in this example).
[0041]
Therefore, the data in the ab section (first connection section: here, section A) of the first MPEG image data is once decoded to obtain decoded image data, and the decoded image data (first connection section). (Decoded image data) is re-encoded by the MPEG encoding method. The re-encoded data created thereby is referred to as interval A re-encoded MPEG image data (first connected interval re-encoded data). In this re-encoding, the transition of the information value related to the VBV buffer occupancy value is started from the information value related to the VBV buffer occupancy value obtained based on the detected first VBV buffer occupancy value related information at the position a. The rate control is performed so as to end up to the information value related to the VBV buffer occupancy value obtained based on the detected second VBV buffer occupancy value related information at the position of d, and re-encoding is performed by the MPEG encoding method. Do.
[0042]
The operation of performing the conventional joint reproduction operation of reproducing to the position of b of the first MPEG image data and then reproducing the data by connecting to the position of d of the second MPEG image data is performed in section A. The following operation is performed using the re-encoded MPEG image data. That is, the first MPEG image data is reproduced up to the position a (start position of section A) of the first MPEG image data, and then the re-encoded MPEG image data of section A is used as the start position of the section. To the end position, and then connected to the d position (connection designated position) of the second MPEG image data to reproduce the data of the second MPEG image data after d. This is realized by providing a connecting reproduction means for performing this operation on the reproduction apparatus side.
[0043]
By using this joint playback operation, it is possible to realize seamless connection playback that has the same content as the original first and second MPEG image data and that does not cause the VBV buffer to fail.
[0044]
In addition, when obtaining re-encoded MPEG image data of the connection section based only on the first MPEG image data side shown in FIG. 8, the position of the connection point d (connection specification position in the second MPEG image data). ) VBV buffer information is required. As described above, the information in the VBV buffer is information at the start or end of MPEG encoding of the last picture in the predetermined section of the MPEG image data. It becomes. Therefore, the position of the connection point (connection specification position) needs to be specified as the boundary of the second predetermined section at least in the second MPEG image data. (That is, the position of the connection point d in the second MPEG image data needs to be specified as the boundary of the second predetermined section.)
Further, when re-encoded MPEG image data of the connecting section is obtained based only on the first MPEG image data side, as described above, the VBV at the position a (starting position of the connecting section A) shown in FIG. Buffer information is also required. However, since the position of a is designated as the boundary of the first predetermined section before the first predetermined time from the connection point (connection designation position) b in the first MPEG image data, the position of the connection point b is set. Regardless, the information of the VBV buffer is obtained at the position a. Therefore, the position of the connection point b in the first MPEG image data does not necessarily have to be specified as the boundary of the first predetermined section.
[0045]
Next, application examples thereof are shown in FIGS. 9 (2) and 9 (3). FIG. 1A is the same as the example shown in FIG. In the example shown in FIG. 8, the re-encoded MPEG image data of the section is obtained based on only the first MPEG image data side, and the joint reproduction is realized. However, only the second MPEG image data side is connected. It is also possible to obtain the re-encoded MPEG image data of the section and realize the joint reproduction. An example of this is shown in FIG. 9 (2), in which re-encoded MPEG image data in the connection section B in the second MPEG image data is used.
[0046]
In FIG. 9 (2), a connection point (connection designation position) in the first MPEG image data is a position i, and a connection point (connection designation position) in the second MPEG image data is a position k. One unit of the first and second predetermined sections, which are units having the information of the VBV buffer described above, is set between ij in the first MPEG image data and between kl in the second MPEG image data. The position l is the boundary position of the second predetermined section after the second predetermined time from the connection point (connection designated position) k in the second MPEG image data. A section having the connection point k as the start position and the position l as the end position is defined as a connection section B (second connection section).
[0047]
The data of the section B (k-1 section) connecting the second MPEG image data is once decoded to obtain decoded image data, and the decoded image data (second connection section decoded image data) is MPEG-coded. Re-encoding is performed using the encoding method. The re-encoded data created thereby will be referred to as re-encoded MPEG image data (second connected interval re-encoded data) in the connection interval B. This re-encoding is started from the information value related to the VBV buffer occupancy value obtained from the transition of the information value related to the VBV buffer occupancy value based on the first VBV buffer occupancy value related information at the position i. The rate control is performed so as to end up to the information value related to the VBV buffer occupation value obtained based on the second VBV buffer occupation value related information at the position, and re-encoding is performed by the MPEG encoding method.
[0048]
Then, using the re-encoded MPEG image data in the connection section B, connection reproduction from the first MPEG image data to the second MPEG image data is performed. That is, the first MPEG image data is reproduced up to the connection point i (connection designated position) of the first MPEG image data, and then the re-encoded MPEG image data of the section B is ended from the start position of the section. To the position, and then connected to the position 1 of the second MPEG image data (end position of the connecting section B) to reproduce the data of the second MPEG image data after the position l. . This is realized by providing a connecting reproduction means for performing this operation on the reproduction apparatus side.
[0049]
By using this joint playback operation, it is possible to realize seamless connection playback that has the same content as the original first and second MPEG image data and that does not cause the VBV buffer to fail.
[0050]
In addition, when obtaining re-encoded MPEG image data of a section connected based only on the second MPEG image data side shown in FIG. 9B, the position of the connection point i (in the first MPEG image data) Information of the VBV buffer at the connection designated position) is required. As described above, the information in the VBV buffer is information at the start or end of MPEG encoding of the last picture in the predetermined section of the MPEG image data. It becomes. Therefore, the position of the connection point (connection specification position) needs to be specified as the boundary of the first predetermined section at least in the first MPEG image data. (That is, the position of the connection point i in the first MPEG image data needs to be specified as the boundary of the first predetermined section.)
Further, when re-encoded MPEG image data of a connection section is obtained based only on the second MPEG image data side, the position of l shown in FIG. Information on the VBV buffer at position) is also required. However, the position of l is specified as the boundary of the second predetermined section after the second predetermined time from the connection point (connection specification position) k in the second MPEG image data, so that the position of the connection point k is set. Regardless, information on the VBV buffer is obtained at position l. Therefore, the position of the connection point k in the second MPEG image data does not necessarily have to be specified as the boundary of the second predetermined section.
[0051]
Next, an application example shown in FIG. 9 (3) will be described. In this example, the re-encoded MPEG image data of the connection section is obtained based on the first and second MPEG image data before and after the connection point, and the connection reproduction is realized.
[0052]
In FIG. 9 (3), the connection point (connection designation position) in the first MPEG image data is set as the n position, and the connection point (connection specification position) in the second MPEG image data is set as the p position. One unit of the first and second predetermined sections, which are units having the information of the VBV buffer described above, is expressed as mn in the first MPEG image data, and between p-q in the second MPEG image data. To do.
[0053]
The position of m is the boundary position of the first predetermined section before the first predetermined time from the connection point (connection designated position) n in the first MPEG image data. A section having the position of m as the start position and the position of the connection point n as the end position is defined as a connection section A (first connection section). The position of q is the boundary position of the second predetermined section after the second predetermined time from the connection point (connection designated position) p in the second MPEG image data. A section having the connection point p as the start position and the position of q as the end position is defined as a connection section B (second connection section).
[0054]
The data of the connection section A (mn section) of the first MPEG image data is once decoded to obtain decoded image data (connection section A decoded image data: first connection section decoded image data). Further, the data of the segment B (pq segment) connecting the second MPEG image data is once decoded and the decoded image data (joint segment B decoded image data: second segmented decoded image data) is obtained. obtain.
[0055]
The joint section A + B decoded image data (third joint section decoded image data) obtained by combining the joint section A decoded image data and the joint section B decoded image data is re-encoded by the MPEG encoding method. The re-encoded data created thereby is referred to as re-encoded MPEG image data (third re-encoded data of the third connection section) in the connection section A + B. This re-encoding is started from the information value related to the VBV buffer occupancy value obtained based on the first VBV buffer occupancy value related information at the position of m when the transition of the information value related to the VBV buffer occupancy value is The rate control is performed so as to end up to the information value related to the VBV buffer occupation value obtained based on the second VBV buffer occupation value related information at the position, and re-encoding is performed by the MPEG encoding method.
[0056]
Then, using the re-encoded MPEG image data in the connection section A + B, connection reproduction from the first MPEG image data to the second MPEG image data is performed. That is, the first MPEG image data is reproduced until the start position m of the first MPEG image data connection section A, and then the re-encoded MPEG image data of the connection section A + B is ended from the start position of the section. The reproduction is performed up to the position, and then the second MPEG image data after the q position is reproduced by connecting to the end position q of the second MPEG image data connection section B. This is realized by providing a connecting reproduction means for performing this operation on the reproduction apparatus side.
[0057]
By using this joint playback operation, it is possible to realize seamless connection playback that has the same content as the original first and second MPEG image data and that does not cause the VBV buffer to fail.
[0058]
In the example shown in FIG. 9 (3), as described above, information on the VBV buffer at the position m (the start position of the connecting section A) is required. Since the position of m is designated as the boundary of the first predetermined section for the first predetermined time before the connection point (connection designation position) n in the first MPEG image data, regardless of the position of the connection point n. Information on the VBV buffer is obtained at the position m. Therefore, the position of the connection point n in the first MPEG image data is not necessarily designated as the boundary of the first predetermined section.
[0059]
Further, as described above, information on the VBV buffer at the position of q (end position of the connecting section B) shown in FIG. Since the position of q is designated as the boundary of the second predetermined section after the second predetermined time from the connection point (connection specification position) p in the second MPEG image data, regardless of the position of the connection point p. Information of the VBV buffer is obtained at the position of q. Therefore, the position of the connection point p in the second MPEG image data is not necessarily designated as the boundary of the second predetermined section.
[0060]
As described above, the methods shown in FIGS. 9 (1) to 9 (3) are all developed systems capable of realizing seamless and high-quality joint reproduction, as shown in FIG. It is also possible to realize linked reproduction in which the MPEG image data, the second MPEG image data, and the third and fourth MPEG image data are branched halfway as shown in the figure. As described above, by using the present invention, it is possible to freely connect to other MPEG data simply by generating and using the re-encoded MPEG image data in the connecting section without processing the original MPEG image data itself. Therefore, even when a program that constitutes various branch stories is encoded, it is possible to efficiently use the media without recording redundant MPEG image data of the entire story for each branch story. (If the present invention is used, one set of each of the first to fourth MPEG image data and the re-encoded MPEG image data of the connecting section for each branch story may be prepared.)
If the method shown in FIG. 9 (3) is used, as described above, the position of the connection point in the first MPEG image data does not necessarily have to be specified as the boundary of the first predetermined section. Since the position of the connection point in the MPEG image data does not necessarily need to be specified as the boundary of the second predetermined section, the information of the VBV buffer is smaller than the predetermined section unit described as side information in the predetermined section unit. This can be applied when editing with accuracy, for example, in units of one frame. This example will be described with reference to FIG. The predetermined unit may be about 3 frames or about 1 GOP, but here it is 1 GOP.
[0061]
Assume that there are two MPEG streams to be connected as shown in FIG. At the points g and h indicated by arrows in the first MPEG stream, the VBV buffer information at the position g and the VBV buffer information at the position h are described in the VBV buffer information list. . The second MPEG image data also includes information on the VBV buffer at position i and information on the VBV buffer at position j.
[0062]
When connecting from the position of p of the first MPEG stream 1 to the head of the second MPEG stream, the data of the section A from g to p of the first MPEG stream is decoded, and further, the second MPEG stream The data of the section B from i to j is decoded, and both images are re-encoded so that the buffer transition starts from the buffer occupation value at the position g and becomes the buffer occupation value at the position j.
[0063]
If the data thus created is referred to as re-encoded MPEG image data in the section A + B, reproduction is performed up to the position p of the first MPEG image data, which is a conventional reproduction operation, and then the second MPEG image is reproduced. The operation of connecting to the data and reproducing the data is to reproduce up to the position of g of the first MPEG image data, and then reproduce the re-encoded MPEG image data of the section A + B, and then the second MPEG image data. By connecting to the MPEG image data j and reproducing the data, it is possible to perform seamless connection reproduction with the same content and without causing the VBV buffer to fail.
[0064]
Next, two methods for realizing connected reproduction similar to the above-described examples without describing the information of the VBV buffer as side information will be described. (A method for calculating the information value related to the VBV buffer occupation value, which is necessary when generating the re-encoded data of the connected sections will be described.)
First, the first method will be described. In the MPEG standard, basically, in the case of CBR (constant bit rate), that is, a fixed transfer rate, a VBV delay value indicating the buffer occupancy rate of the VBV buffer is defined in the MPEG video picture layer. In this case, since the VBV delay value is described in units of pictures, by observing the MPEG image bitstream only with the picture header alone, the MPEG encoding start time (or the picture corresponding to the predetermined position of the MPEG image data) (or VBV buffer occupancy value at the time of termination) can be detected. In this case, for example, the function of the VBV buffer information detector 33 in FIG. 4 to be described later is to search for a picture header of a bit stream (a 4-byte code of 0x00000100 in MPEG), and then 10-bit temporal reference 10 bits, This can be achieved by detecting the VBV delay 16 bits following the picture coding type 3 bits. What is VBV delay value?
VBV delay = 90000 x B / R
B: Buffer occupancy value R: Since it is defined by the bit rate, in the case of a fixed rate, the VBV buffer occupancy value can also be obtained by calculation from the VBV delay value using this bit rate. (For example, the calculation is performed by the VBV buffer information detector 33 shown in FIG. 4.)
In MPEG, it is necessary to pay attention to the VBV delay value at the vertex position of the graph as shown in FIG.
[0065]
Next, the second method will be described. This is the case for a variable transfer rate rather than a fixed transfer rate. In the MPEG standard, basically, in the case of VBR (variable bit rate), the VBV delay value indicating the buffer occupancy of the VBV buffer in the MPEG video picture layer is all 1 (0xffff because all 16 bits are 1). It becomes. Therefore, the first method cannot be used.
[0066]
Therefore, the following calculation is performed from the information obtained by observing the MPEG image bit stream. First, it is assumed that the VBV buffer is occupied from the very beginning of the bitstream up to the maximum value defined by MPEG (for example, 1.75 Mbit in the main profile main level). Next, the code amount of the first picture is subtracted. Next, using the transmission rate information of the peak rate in variable transfer rate coding, the transmission amount when the time between display pictures has elapsed is added, and the coding amount of the next picture is subtracted. By repeating such a series of addition and subtraction processes up to a predetermined bitstream position, a picture corresponding to a predetermined position in the MPEG image data is obtained by simulating a graph as shown in FIG. The VBV buffer occupation value at the MPEG encoding start time (or end time) can be obtained. The peak rate at the time of the variable transfer rate is specified in the syntax part called bit rate of the sequence header in MPEG, and can be obtained by referring to it.
[0067]
For example, the VBV buffer information detector 33 shown in FIG. 4 to be described later is realized by providing the above-described MPEG image bit stream with an observation function and a calculation function. (In the case of the second method, the generated code amount of each picture must be observed and calculated from the head of the MPEG image bitstream. However, as in the first method, information in the VBV buffer is previously used as side information. There is no need to prepare.)
Next, a brief description will be given of the generation of re-encoded data for connected sections when the first and second methods are used. In addition, since the joint reproduction | regeneration operation | movement using this connection area re-encoding data is the same as the case where the connection area re-encoding data produced | generated by the information of the VBV buffer previously recorded as side information is used, here Description is omitted.
[0068]
When obtaining the re-encoded MPEG image data of the connection section based only on the first MPEG image data side shown in FIG. 9A, the connection point (connection designation position) b in the first MPEG image data is the second one. A section having a position a before one predetermined time as a start position and a connection designation position b in the first MPEG image data as an end position is defined as a first connection section (connection section A). The restriction such as the boundary of the first predetermined section as in the case of using the side information is not necessary for specifying the start position a of the connection section A. Similarly, there is no need to limit the boundary of the second predetermined section as in the case of using side information for specifying the connection point (connection specification position) d in the second MPEG image data.
[0069]
The data of the ab section (joining section A) of the first MPEG image data is once decoded to obtain decoded image data, and the decoded image data (first joining section decoded image data) is re-encoded by the MPEG encoding method. Encoding is performed to obtain re-encoded MPEG image data (first joint section re-encoded data) in the joint section A. In this re-encoding, the transition of the VBV buffer occupancy value is the MPEG encoding of the picture corresponding to the position a calculated by the first or second method (the MPEG code at the time of generating the first MPEG image data). ) Start from the VBV buffer occupancy value at the start (or end). Then, the transition of the VBV buffer occupancy value is calculated by the first or second method, and the MPEG encoding of the picture corresponding to the position d (MPEG encoding at the time of generating the second MPEG image data) is started. The rate control is performed to re-encode with the MPEG encoding method so as to end up to the VBV buffer occupation value at (or the end time). The obtained re-encoded MPEG image data of the connection section A (first connection section re-encoded data) is recorded on the recording medium. (For example, recording is performed by a data writing unit 37 shown in FIG. 4 described later.)
Next, a case will be described in which re-encoded MPEG image data in a section is obtained based only on the second MPEG image data side shown in FIG. In FIG. 9 (2), a connection point (connection designation position) in the first MPEG image data is a position i, and a connection point (connection designation position) in the second MPEG image data is a position k. A section of the second MPEG image data having a connection point k as a start position and a position l after the second predetermined time from the connection point (connection specification position) k as an end position is connected to a connection section B ( Second connecting section). A restriction such as the boundary of the second predetermined section as in the case where the side information is used to specify the end position 1 of the connection section B is not necessary. Similarly, there is no need to limit the boundary of the first predetermined section as in the case where the side information is used for specifying the connection point (connection specification position) i in the first MPEG image data.
[0070]
The data of the connecting section B (k-1 section) of the second MPEG image data is once decoded to obtain decoded image data, and the decoded image data (second connecting section decoded image data) is MPEG-encoded. Re-encoding is performed according to the method to obtain re-encoded MPEG image data (second connection interval re-encoded data) of the connection interval B. In this re-encoding, the transition of the VBV buffer occupancy value is calculated by the above first or second method, and the VBV buffer occupancy at the MPEG encoding start time (or end time) of the picture corresponding to the position i is calculated. Start with a value. The transition of the VBV buffer occupancy value ends up to the VBV buffer occupancy value calculated at the MPEG encoding start point (or end point) of the picture corresponding to the position l calculated by the first or second method. As described above, rate encoding is performed and re-encoding is performed using the MPEG encoding method. The re-encoded MPEG image data (second connected section re-encoded data) of the obtained connecting section B is recorded on the recording medium. (For example, recording is performed by a data writing unit 37 shown in FIG. 4 described later.)
Next, a case where re-encoded MPEG image data in a section is obtained based on the first and second MPEG image data before and after the connection point shown in FIG. 9 (3) will be described.
[0071]
In FIG. 9 (3), the connection point (connection designation position) in the first MPEG image data is set as the n position, and the connection point (connection specification position) in the second MPEG image data is set as the p position.
[0072]
Let m be a position a first predetermined time before a connection point (connection designated position) n in the first MPEG image data. A section of the first MPEG image data having the position of m as the start position and the position of the connection point n as the end position is defined as a connection section A (first connection section). The position after the second predetermined time from the connection point (connection designated position) p in the second MPEG image data is q. A section of the second MPEG image data having the connection point p as the start position and the position of q as the end position is defined as a connection section B (second connection section).
[0073]
In order to specify the start position m of the connection section A, there is no need to restrict the first predetermined section as in the case of using side information. Similarly, there is no need to limit the boundary of the second predetermined section as in the case of using side information to specify the end position q of the connection section B.
[0074]
The data of the connection section A (mn section) of the first MPEG image data is once decoded to obtain decoded image data (connection section A decoded image data: first connection section decoded image data). Also, the data of the connection section B (pq section) of the second MPEG image data is once decoded to obtain decoded image data (connection section B decoded image data: second connection section decoded image data). .
[0075]
Then, the joint section A + B decoded image data (third joint section decoded image data), which is a combination of the joint section A decoded image data and the joint section B decoded image data, is re-encoded by the MPEG encoding method. The re-encoded data created thereby is assumed to be re-encoded MPEG image data (third connected interval re-encoded data) in the connection interval A + B. In this re-encoding, the transition of the VBV buffer occupancy value is calculated by the first or second method, and the VBV buffer occupancy at the MPEG encoding start time (or end time) of the picture corresponding to the position of m is calculated. Start with value. The transition of the VBV buffer occupancy value ends up to the VBV buffer occupancy value calculated at the MPEG encoding start time (or end time) of the picture corresponding to the position q calculated by the first or second method. As described above, rate control is performed and re-encoding is performed using the MPEG encoding method. The resulting re-encoded MPEG image data (third re-encoded data) is recorded on a recording medium. (For example, recording is performed by a data writing unit 37 shown in FIG. 4 described later.)
Also in the example shown in FIG. 10, it is of course possible to obtain the VBV buffer occupancy value at a required position by the above-described calculation method, and to obtain desired connected section re-encoded data).
[0076]
Next, VBV buffer information to be recorded on the recording medium by one embodiment of the recording / reproducing apparatus to which the present invention is applied (at the time of starting or ending the MPEG encoding of the last picture in the predetermined section of the MPEG image data) VBV buffer occupancy value related information indicating the information value related to the VBV buffer occupancy value, and address information indicating where the information value related to the VBV buffer occupancy value is the information value related to the VBV buffer occupancy value in the MPEG image data) The recording structure related to MPEG image data will be described in detail. MPEG image data, which is image data compressed by the MPEG encoding method, is recorded on the recording medium. The MPEG image data is recorded as a bit stream in which a plurality of continuously reproducible data encoded and generated in one recording unit is continuously connected.
[0077]
In addition to the encoded MPEG image data bit stream, the VBV buffer value (occupancy value) at the end of picture encoding one frame before the I picture in the MPEG image data bit stream, and 1 P picture The VBV buffer value (occupancy value) at the end of picture encoding before the frame, and address information indicating the VBV buffer occupancy value at which position in the MPEG image data each VBV buffer value (in this example, an MPEG image) The relative address from the beginning of the data file is recorded. A data structure of VBV buffer information including these data is shown in FIG.
[0078]
VBV buffer information has a hierarchical structure. There is an entry point information structure first, followed by a VBV information structure. In the entry point information structure, first, the number of addresses of entry points (EP) is described in 32 bits, and then an EPn (n is a natural number of 1 or more) address is described in 32 bits in order. The EPn address indicates a position where EPn information (n is a natural number of 1 or more) of the VBV information structure is described, and describes a relative address from the top of the VBV buffer information. On the other hand, the VBV information structure is described in order from the EP1 information, and the contents of the EP1 information describe the relative address, the PTM value, and the VBV value in order.
[0079]
As shown in FIG. 2, the relative address in the EPn information of the VBV information structure means the end of picture encoding one frame before the I picture in the bit stream of MPEG image data, and the end of picture encoding one frame before the P picture. This is a relative address from the beginning of the MPEG image data at the time point and at the end of recording. For example, the unit is a byte. When recorded on a disk medium, a sector or the like is used as a relative address.
[0080]
The PTM value in the EPn information of the VBV information structure is a time stamp recorded with a clock of 90 kHz or 27 MHz in the MPEG system standard (multiplexing standard). In the MPEG standard, it is called PTS (Presentation Time Stamp) or DTS (Decoding Time Stamp). Here, the DTS is recorded as time information at the end of picture encoding one frame before the I picture of the bit stream of the MPEG image data, at the end of picture encoding one frame before the P picture, and at the end of recording. . One DTS is recorded in one picture, and an NTSC video signal is recorded at an interval of 3003 clocks per picture with a 90 kHz clock. Therefore, when there is an I picture or a P picture every three pictures as in the present invention, and the first starts from 0, the PTM information is EPn information at intervals of 9009, 18018. Will be described.
[0081]
The VBV value in the EPn information of the VBV information structure is a virtual buffer occupation value of the decoder defined by MPEG. This can be derived from the amount of generated code for each picture of the MPEG image data and the transfer rate value. As shown in FIG. 3, the picture code one frame before the I picture and P picture of the compressed bitstream information Describe the VBV occupation value at the position of ○ in the figure at the end of conversion. Or, describe the VBV delay value specified by MPEG. This value is a value converted to the time it takes to reach the VBV occupation value at the transfer rate at that time. In the present invention, any information regarding the VBV buffer occupation value may be used. FIG. 17 shows the relationship between the VBV buffer occupancy value and the VBV delay value. The occupancy value OCC of the VBV buffer has a relationship of VBV delay = 90000 * OCC / R, where R is the encoding rate, and 90000 is a value for indicating a count number of 90 kHz.
[0082]
In MPEG compression, encoding is basically performed using I or P picture types in units of 3 frames such as IBB and PBB. In MPEG compression, B picture may be predicted from both directions, so in the encoded bit stream order, data linkage is added only at the end of picture encoding one frame before the I picture and P picture of the bit stream. Is not easy. For this reason, the present invention is described on the assumption that VBV information is described at the end of picture encoding one frame before the I picture and P picture of the bit stream.
[0083]
However, in essence, an information value related to the VBV occupation value may be included in each picture. Further, the encoding start point may be used instead of the picture encoding end point. FIG. 16 (1) is a conceptual diagram in the case of having a value of the encoding end point in the list, but in this case, there is no information value regarding the first VBV occupation value, so there is a virtual before the first frame. As a result, the information value related to the VBV occupancy value at the end of encoding of the virtual frame is calculated as an initial value. The calculation is performed by adding the first picture code amount to the information value related to the first VBV occupancy value, and from the added value, from the gradient due to the encoding rate, how much code is required in the time of (1 / picture rate) By subtracting the calculated value of the transmission amount, the initial value of the black circle part in FIG. FIG. 16 (2) is a conceptual diagram in the case of having the value of the encoding start point in the list. In this case, since there is no information value regarding the last VBV occupation value, a virtual is behind the last frame. If there is a specific frame, the information value related to the VBV occupancy value at the start of encoding of the virtual frame is calculated as the final value. The calculation subtracts the final picture code amount from the information value related to the last VBV occupancy value, and from the subtracted value, from the gradient by the encoding rate, how much code transmission amount in the time of (1 / picture rate) When the calculated values are added, the final value of the black circle portion in FIG. 16 (2) is obtained.
[0084]
Next, the configuration of an embodiment of a recording / reproducing apparatus to which the present invention is applied is shown in FIG. 4, and the operation of creating VBV buffer information while encoding image data by the MPEG encoding method will be described.
[0085]
When there is no encoded data in the recording medium 31, that is, when encoding is performed for the first time, the data reading unit 32 from the recording medium 31 indicates that there is no data, so information that there is no data is indicated as VBV buffer information. Transmit to detector 33. Since no data exists in the VBV buffer information detector 33, the initial value set in advance in the parameter setting unit 34, that is, the VBV value is set to, for example, 80% of the maximum value of VBV defined by MPEG. The time stamp information is 0. These initial set values are transmitted to the image encoder 35.
[0086]
The image encoder 35 starts encoding from an initial set value. In the image encoder 35, while encoding, the generated code amount, PTM value, and VBV value at the end of picture encoding one frame before the I picture of the bit stream and one frame before the P picture are Transmit to the VBV buffer information creator 36. At the same time, the encoded data is transmitted to the data writing unit 37. Further, the image encoder 35 transmits the generated code amount, the PTM value, and the VBV value when the user temporarily stops or ends the image compression recording to the VBV buffer information creator 36.
[0087]
The VBV buffer information creator 36 creates VBV buffer information data having the structure shown in FIG. 1 from the generated generated code amount value, PTM value, and VBV value. Alternatively, data necessary for creating the data structure is stored in memory and recorded and held in a predetermined format. The information created by the VBV buffer information creator 36 may be written in bursts simultaneously when encoded data (MPEG image data) is written on the recording medium 31 by the data writing unit 37. The information generated by the VBV buffer information generator 36 is recorded and held in a predetermined format after the encoded data (MPEG image data) has been written, that is, after the user has paused or ended the image compression recording. The written data may be converted into the structure shown in FIG.
[0088]
Next, in the case where the first and second MPEG image data recorded on the recording medium 31 are re-encoded for the section A in order to enable joint reproduction from a predetermined position. Will be described with reference to FIG.
[0089]
First, from a user interface (not shown), the user designates from which point of the first and second MPEG image data already recorded to be connected and reproduced.
[0090]
The recording medium 31 has already recorded the first and second MPEG image data (compressed encoded stream) and the VBV buffer information generated by the recording / reproducing apparatus shown in FIG. Therefore, the data reading unit 32 shown in FIG. 4 reads the VBV buffer information, and the VBV value, the PTM value, and the relative value at the position a in FIG. Get an address.
[0091]
When the connection playback position is specified from the user interface, for example, when the specification method is position information of the relative address of the data, the value closest to the relative address information in the EPn information of the structure of the VBV buffer information is set. Use VBV and PTM values linked to data. Also, if the method of designation is the time from the start time of the data or the time stamp information of the points to be played back, the PTM value in the EPn information of the structure of the VBV buffer information is similarly used, When this value is recorded with a clock of 90 kHz, the time of the second can be obtained by multiplying the value by the value of 1/90000 second, the position (relative address) for replaying the connection, VBV value, PTM A value can be obtained.
[0092]
These values are input to the parameter setter 34, and the image encoder 35 starts encoding from the set values. On the other hand, the encoded data search unit 38 searches the bit stream already recorded for the start position of the section A to be re-encoded. In the search, a pointer is set at a position from the head of the bit stream file using the relative address of the data.
[0093]
The image encoder 35 decodes the first MPEG image data corresponding to the section A, and the transition of the VBV buffer occupancy value is started again from the VBV value at the position a using the decoded image. The rate control is performed so that the process ends up to the VBV value at the position, and re-encoding is performed by the MPEG encoding method. For re-encoding, an image completely decoded as described above may be used, but a code amount control technique on a bit stream as disclosed in Japanese Patent Laid-Open No. 11-234677 may be used.
[0094]
Here, if the section A to be re-encoded is longer than the minimum unit of the VBV buffer information, the re-encoding occurs at the end of picture encoding one frame before the I picture and P picture of the bit stream. The code amount, the PTM value, and the VBV value are transmitted to the VBV buffer information creator 36 each time. At the same time, the re-encoded data is transmitted to the data writing unit 37.
[0095]
The VBV buffer information creator 36 creates data having the structure shown in FIG. 1 from the input generated code amount value, PTM value, and VBV value. Alternatively, data necessary for creating the data structure is stored in memory and recorded and held in a predetermined format. The information in the VBV buffer information generator 36 may be written in bursts at the same time when the encoded data is written, or when the encoded data is written, that is, the user compresses the image. Writing may be performed by converting the data recorded and held in a predetermined format when recording is temporarily stopped or ended into the structure of FIG.
[0096]
The re-encoded image data of section A (joined section A re-encoded data) is recorded as a separate file separated from the first and second MPEG image data. Alternatively, recording is performed by connecting to the head of the second recorded MPEG image data.
[0097]
First MPEG image data, second MPEG image data, information on the VBV buffer occupancy value and data address information thereof, re-encoded image data of section A (or re-encoded image data of section B, Alternatively, the re-encoded image data of the section A + B) may be recorded on the same recording medium, recorded on a plurality of recording media in any combination, or recorded on different recording media. It doesn't matter. In the case of being recorded separately on a plurality of recording media, it indicates that they are the same information group so that each recording medium is linked and operated (each data and information is linked). Information, such as an ID, may be recorded on each recording medium. The first MPEG image data, the second MPEG image data, and the re-encoded image data of the section A (or the re-encoded image data of the section B or the re-encoded image data of the section A + B). When recorded on the same recording medium, it is possible to control splice playback on the playback apparatus side with a single recording medium.
[0098]
If the information related to the VBV buffer occupancy value for obtaining the re-encoded image data of the connected section is not read from the side information recorded on the medium but calculated, the information about the VBV buffer occupancy value and its There is no need to record data address information.
[0099]
In the above embodiment, the recording medium is described as a recording medium in the recording / reproducing apparatus. However, the recording medium may be a recording medium detachably attached to the recording / reproducing apparatus or a recording medium (database) via a network.
[0100]
In the above embodiment, an example in which image data is connected by focusing on single MPEG image data has been described. However, in the MPEG transport stream, which is MPEG multiplexed data that is packet-multiplexed by the MPEG method together with audio data or the like. This may be applied when connecting MPEG image data.
[0101]
In many cases, variable-length-encoded MPEG image data, fixed-length-encoded MPEG 1 layer 2 audio, AC3, or the like are multiplexed in the transport stream. Therefore, when connecting MPEG image data, which is one of the element encoded data in the multiplexed data, a connection method that takes into account the consistency of the STD buffer (VBV buffer in video) defined by MPEG at the point of connection As described above, the method of the embodiment described above may be applied.
[0102]
For example, the first and second MPEG image data to be connected are extracted from the first and second MPEG transport streams, respectively, and connected in the same manner as in the above-described embodiment. Linked segment re-encoded data (re-encoded image data of interval A, re-encoded image data of interval B, re-encoded image data of interval A + B) used for splicing reproduction is packet-multiplexed by the MPEG method. The generated MPEG multiplexed data may be recorded.
[0103]
The state shown in FIG. 14 (1) indicates the state of the packet multiplexed data of the MPEG transport stream. A packet described as V is a video packet, a packet described as A is an audio packet, and a packet described as S is an information packet such as PAT or PMT used in the system. It is recorded in a form that complies with the rules of each MPEG2 system. The video packet has a light gray color. The state showing these as a whole is FIG. The state where only the video packets are collected is shown in FIG. The contents of this video packet are typically an I picture, followed by two B pictures, followed by one P picture, as shown in Figure 4 (4). is there.
[0104]
The code amount is adjusted by re-encoding in one or more of these pictures. For example, FIG. 5 shows a state in which the code amount is reduced. The code amount of each picture is small. The packetized state in this state is FIG. The reduced area is black. This packet reduces the overall amount of video. Then rebuild the TS. This state is expressed as a whole (7). FIG. 8 is an enlarged view of FIG. As a result, a part of the V packet is reduced, and the other element data packets are multiplexed as they are.
[0105]
In the MPEG system, PCR clock information must be recorded once every 100 msec. Since the data length is changed, the PCR clock information described in each element packet is changed as necessary. In addition, PTS and DTS are described in a packet in which the PES header at the head of an access unit (frame or field picture unit) is present in the video packet. In the audio packet, one or a plurality of audio frames are packed with PES, and the PTS is described in the packet having the head PES header. These time stamp information does not need to be changed if the number of pictures is not increased or decreased in the image, and the audio does not need to be changed unless the playback time length is increased or decreased. Add and modify appropriate PTS and DTS.
[0106]
Furthermore, when simply re-encoding, the GOP unit from the I picture that is the reset timing of predictive encoding is easy to handle, but when the GOP is not independent, that is, the B picture at the boundary is the GOP of both sides. The last reference picture of the previous GOP is decoded and stored in an image re-encoding memory (not shown) or the like. It may be necessary to keep it.
[0107]
First MPEG multiplexed data (first MPEG transport stream), second MPEG image data (second MPEG transport stream), information on the VBV buffer occupancy value, its data address information, and the section A spliced section generated by packet multiplexing according to the MPEG method including A recoded image data (or the recoded image data of the section B or the recoded image data of the section A + B) as element coded data The MPEG multiplexed data may be recorded on the same recording medium, recorded on a plurality of recording media in any combination, or recorded on different recording media. In the case of being recorded separately on a plurality of recording media, it indicates that they are the same information group so that each recording medium is linked and operated (each data and information is linked). Information, such as an ID, may be recorded on each recording medium. First MPEG multiplexed image data, second MPEG multiplexed image data, re-encoded image data of section A (or re-encoded image data of section B, or re-encoded image of section A + B) (Data) splicing section MPEG multiplexed data is recorded on the same recording medium, it is possible to control splicing playback on the playback device side with a single recording medium.
[0108]
【The invention's effect】
As described above, according to the present invention, the first MPEG multiplexed data packet-multiplexed including the first and second MPEG image data (or the first MPEG image data as the element encoded data). And packet-multiplexed second MPEG multiplexed data including the second MPEG image data as element encoded data) from the first MPEG image data at each designated connection designation position. When connected to the second MPEG image data and played back (when played back from the first MPEG multiplexed data to the second MPEG multiplexed data), the connection of the VBV buffer has overflow or underflow. Seamless and high-quality playback can be realized without any contradiction.
[0109]
Further, in the present invention, the image data to be newly generated / recorded in order to realize seamless and high-quality reproduction may be only re-encoded data of the set connection section. The recording medium for recording can be used efficiently.
[Brief description of the drawings]
FIG. 1 is a diagram showing a VBV buffer information structure based on an embodiment of a recording / reproducing apparatus to which the present invention is applied.
FIG. 2 is a diagram illustrating a relationship between MPEG image data and a relative address in one embodiment.
FIG. 3 is an explanatory diagram illustrating a VBV value in one embodiment.
FIG. 4 is a block diagram showing an embodiment of a recording / reproducing apparatus to which the present invention is applied.
FIG. 5 is a diagram illustrating an example of a conventional MPEG encoder.
FIG. 6 is a diagram illustrating an example of a conventional MPEG decoder.
FIG. 7 is a diagram for explaining the concept of a VBV buffer in MPEG.
FIG. 8 is a diagram for explaining a concept of splicing reproduction that can be realized by the present invention;
FIG. 9 is a diagram for explaining a concept of splicing reproduction that can be realized by the present invention.
FIG. 10 is a diagram for explaining a concept of splicing reproduction that can be realized by the present invention.
FIG. 11 is an explanatory diagram showing a conventional MPEG multiplexing system.
FIG. 12 is an explanatory diagram showing the relationship between MPEGTS, PS, and PES.
FIG. 13 is an explanatory diagram showing an example of use of MPEGTS PSI.
FIG. 14 is an explanatory diagram showing an arrangement of MPEGTS packets.
FIG. 15 is a diagram for explaining a concept of splicing reproduction that can be realized by the present invention;
FIG. 16 is a diagram for explaining an information value related to a VBV buffer occupation value according to an embodiment;
FIG. 17 is a diagram illustrating a relationship between a VBV buffer occupation value and a VBV delay value.
[Explanation of symbols]
31 Recording medium 32 Data reading unit 33 VBV buffer information detector 34 Parameter setting unit 35 Image encoder 36 VBV buffer information creation unit 37 Data writing unit 38 Encoded data search unit

Claims (1)

The first and second MPEG image data, which are image data encoded by the MPEG encoding method and recorded on the same recording medium , are stored at the specified connection specification positions in the respective MPEG image data. Recording means for generating and recording third linked section re-encoded data encoded by the MPEG encoding method as data to be reproduced by connecting from one MPEG image data to the second MPEG image data An MPEG data recording device provided with
The recording means includes
A section having a start position in the first MPEG image data as a start position and a end position at the connection specified position in the first MPEG image data is a first connection. A section having a connection designated position in the second MPEG image data as a start position and a position after a second predetermined time from the connection designated position in the second MPEG image data as an end position. As a second connecting section, and a section combining the first connecting section and the second connecting section as a third connecting section,
Decoding the first joint section decoded image data, which is image data obtained by decoding the first MPEG image data in the first joint section, and the second MPEG image data in the second joint section. The third joint section decoded image data composed of the second joint section decoded image data, which is the image data obtained as described above, is re-encoded by the MPEG encoding method, and the third joint section re-encoded data is obtained. Re-encoding means for generating , and recording the third linked section re-encoded data in an area different from each area where the first and second MPEG image data are recorded on the same recording medium It is what
The re-encoding means, during the re-encoding, changes the information value related to the VBV buffer occupancy value at the time of encoding the first MPEG image data at a position corresponding to the start position of the first connection section. Starting from the information value related to the VBV buffer occupancy value, and ends up to the information value related to the VBV buffer occupancy value at the time of encoding the second MPEG image data at the position corresponding to the end position of the second connection interval. The code amount is controlled as described above and re-encoding is performed.
MPEG data recording apparatus characterized by the above.

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