WO2006018887A1

WO2006018887A1 - Medium distribution device, medium reception device, and medium transmission system

Info

Publication number: WO2006018887A1
Application number: PCT/JP2004/011923
Authority: WO
Inventors: Yuichi Idehara; Junichi Yokosato; Ikuro Ueno; Fuminobu Ogawa
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2004-08-19
Filing date: 2004-08-19
Publication date: 2006-02-23
Also published as: JP4361564B2; JPWO2006018887A1

Abstract

A config-ID identifying config information required when a medium distribution device [1] restores medium data is inserted into RTP payload headers (1) to (4) of RTP packets and the respective RTP packets are distributed. On the other hand, a medium reception device [2] extracts a config-ID from the RTP payload header of one of the RTP packets, references the table, identifies the config information corresponding to the config-ID, and restores medium data from each bit stream by using the config information.

Description

Specification

Media distribution device, media reception device, and media transmission system

Technical field

[0001] The present invention relates to a media distribution device that packetizes and distributes media data, a media reception device that receives media data distributed from the media distribution device, and a media transmission system that includes the media distribution device and the media reception device. It is about.

Background art

[0002] JPEG2000 (ITU_T T. 800 / ISO / IEC 1 5444—1) data transmission is the most important for JPEG2000 data when the purpose is to perform data transmission as efficiently as possible in poor quality networks. there is a need force ^s to not drop as much as possible the main header.

If transmission of the main header fails, all other data can be received correctly, but no image can be decoded from the JPEG2000 data.

[0003] The conventional media transmission system has the following measures to prevent the main header from being lost as much as possible.

The media distribution device of the media transmission system inserts the main header into the first RTP (IETF R FC3550) packet, divides the bit stream of the media data, and inserts it into each subsequent RTP packet.

[0004] Further, the media distribution device describes the main header flag for all RTP packets.

However, the flag value of the main header flag is a value of “0” — “15” (value expressed in 4 bits), and the same flag value is described in the RTP packets of the same bit stream as the split source It is done. The flag value is incremented every time the main header is updated.

[0005] When a media receiving device of a media transmission system receives an RTP packet in which a main header is inserted from a media distribution device, the media header is paired with a flag value of a main header flag described in the RTP packet. save.

When the media receiving device receives the subsequent RTP packet from the media distribution device, the media receiving device The media data is restored from the bit stream inserted in the subsequent RTP packet with reference to the header.

[0006] However, when the main header is inserted and the RTP packet is missing, the media receiving apparatus checks the flag value of the main header flag described in the subsequent RTP packet.

Then, in the main header received and saved in the past, the main header to which the same flag value is added is searched.

If there is a main header to which the same flag value is added, the media receiving device refers to the main header and restores the media data from the bit stream inserted in the subsequent RTP packet (for example, patent document). 1).

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2003-209839 (paragraph numbers [0051] to [0057], FIG. 1)

[0008] Since the conventional media transmission system is configured as described above, the main header flag described in the subsequent RTP packet in the main header received and stored in the past. If there is a main header with the same flag value as that of, the media data can be restored from the bit stream inserted in the subsequent RTP packet by referring to the main header. . However, the flag value of the main header flag is incremented each time the main header is updated, and when the number of updates increases, the flag value used in the past is used again, so that the subsequent RTP packet Even if there is a main header with the same flag as the flag value of the described main header flag, the main header is different from the main header inserted in the missing RTP packet, and the subsequent RTP packet There was a problem that media data could not be restored even though it could be received correctly.

[0009] The present invention has been made to solve the above-described problem, and even if reception of an RTP packet in which a main header is inserted fails, a bit inserted in a subsequent RTP packet. It is an object of the present invention to obtain a media transmission system and a media receiver capable of restoring media data from a stream.

Another object of the present invention is to provide a media distribution device capable of notifying the media reception device of identification information specifying the main header. Disclosure of the invention

[0010] In the media transmission system according to the present invention, the media distribution device inserts identification information for specifying the decoding parameter into the payload of each packet and distributes each packet, while the media reception device transmits any packet. The identification information is extracted from the payload, the decoding parameter corresponding to the identification information is identified by referring to the table, and the media data is restored from each bit stream power using the decoding parameter. is there.

[0011] By this, even if reception of the RTP packet in which the main header is inserted fails, the bit stream force media data inserted in the subsequent RTP packet can be recovered.

Brief Description of Drawings

FIG. 1 is a configuration diagram showing a media transmission system according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram showing a format example of a JPEG2000 encoded code stream.

FIG. 3 is an explanatory diagram showing the structure of a general RTP packet.

FIG. 4 is an explanatory diagram showing a method in the case of RTP transmission of general still image data.

FIG. 5 is an explanatory diagram showing a method in the case of RTP transmission of PEG2000 still image data.

FIG. 6 is an explanatory diagram showing a table in which a correspondence relationship between config—ID and config information is recorded.

FIG. 7 is an explanatory diagram showing a configuration of an RTP packet distributed by the media distribution device.

[FIG. 8 is an explanatory diagram showing the method of Embodiment 1 when PEG2000 still image data is RTP-transmitted.

[FIG. 9 is an explanatory diagram showing the method of Embodiment 2 when PEG2000 still image data is RTP-transmitted.

FIG. 10 is an explanatory diagram showing a table update process.

FIG. 11 is an explanatory diagram showing a table update process.

[FIG. 12 is an explanatory diagram showing the method of Embodiment 4 when PEG2000 still image data is RTP-transmitted.

[Figure 13 shows the method of Embodiment 5 when UTP2000 still image data is transmitted via RTP. FIG.

FIG. 14 is an explanatory diagram showing information included in difference information of config information.

FIG. 15 is an explanatory diagram showing a specific example of changing config information using the difference information description format of FIG.

FIG. 16 is an explanatory diagram showing an example of bit stream division;

FIG. 17 is an explanatory diagram showing a process for complementing missing RTP packets in part.

FIG. 18 is an explanatory diagram showing an example of bitstream division.

FIG. 19 is an explanatory diagram showing a process for complementing a part of missing RTP packets.

FIG. 20 is an explanatory diagram showing bucketing of a bit stream.

FIG. 21 is an explanatory diagram showing a process for complementing missing RTP packets in part.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.

FIG. 1 is a block diagram showing a media transmission system according to Embodiment 1 of the present invention.

[0014] In the figure, the media distribution device 1 has config information (main header) that is a decryption parameter.

+ Insert the config_ID (identification information) specifying the tile part header) into the RTP payload header of each RTP packet and distribute each RTP packet.

When the media receiving device 2 receives each RTP packet delivered from the media delivery device 1, the media receiving device 2 extracts config_ID from the RTP payload header of any RTP packet, refers to the table, and corresponds to the config-ID. Identify the config information and use that config information to recover the media data from the bitstream inserted in each RTP packet.

[0015] When the data dividing unit 11 of the media distribution device 1 receives the media data to be distributed, it divides the bit stream of the media data. The data dividing unit 11 constitutes a data dividing unit.

The RTP header construction unit 12 of the media distribution device 1 indicates a time stamp (TS) indicating a display time, a sequence number (SQ) indicating the order of RTP packets, and a break between images. Insert M bits etc. into the RTP header of each RTP packet.

[0016] The RTP payload construction unit 13 of the media distribution device 1 inserts the config information necessary for restoring the media data into the RTP payload of the first RTP packet, and the bit stream divided by the data division unit 11 Enter the RTP payload of subsequent RTP packets in order.

The table storage unit 14 of the media distribution device 1 is a memory that stores a table in which a correspondence relationship between config ID and config information is recorded.

[0017] The RTP payload header construction unit 15 of the media distribution device 1 refers to the table stored in the table storage unit 14, and sets each config-ID corresponding to the config information inserted by the RTP payload construction unit 13. Enter the RTP payload header of the RTP packet. The RTP header construction unit 12, the RTP payload construction unit 13, the table storage unit 14, and the RTP payload header construction unit 15 constitute packet construction means.

The packet delivery unit 16 of the media delivery device 1 constitutes a packet delivery means for delivering each RTP packet in order.

The packet receiver 21 of the media receiver 2 constitutes a packet receiver that receives each RTP packet distributed from the media distributor 1.

The table storage unit 22 of the media receiver 2 is a memory that stores a table in which the correspondence between config—ID and config information is recorded. The table storage unit 22 constitutes a table storage means.

[0019] The config information specifying unit 23 of the media receiving device 2 extracts a config-ID from the RTP payload header of any RTP packet received by the packet receiving unit 21, and stores the table stored in the table storing unit 22 To specify the config information corresponding to the config—ID. The config information specifying unit 23 constitutes a decoding parameter specifying means.

[0020] The media data restoring unit 24 of the media receiving device 2 extracts a bit stream from the RTP payload of each RTP packet received by the packet receiving unit 21, and uses the config information specified by the config information specifying unit 23. Restore media data from each bitstream. The media data restoration unit 24 constitutes media data restoration means. The decoding unit 25 of the media receiver 2 converts the media data restored by the media data restoration unit 24 into image data.

The image playback unit 26 of the media receiver 2 displays an image on the display 27 according to the image data converted by the decoding unit 25.

Next, the operation will be described.

In this first embodiment, an encoded code stream of JPEG2000 (ITU_T T. 800 / ISO / IEC 15444-1) is used and a media distribution protocol of RTP (IETF RFC3550) is used. This is only an example, and is not limited to practical use.

[0022] FIG. 2f is an explanatory diagram showing a format example of a PEG2000 encoded code stream.

Fig. 2 shows the JPEG2000 encoded code stream when the number of tiles is 1 and the number of tile parts is 1. The config information is composed of the main header and tile part header. Bitstream and end code (EOC) are added. Note that the JPEG2000 standard specifies that multiple tile part headers can be included in one image. The explanation is made assuming that there is only one tile header in the middle.

FIG. 3 is an explanatory diagram showing the structure of a general RTP packet. The general RTP packet is composed of an RTP header and an RTP payload. The configuration of the RTP packet in the first embodiment will be described later.

The RTP header includes a time stamp (TS) indicating the display time, a sequence number (SQ) indicating the order of the RTP packets, and an M bit indicating a break between images. A bit stream of media data is stored in the RTP payload. If the media data is image data, the image data is stored.

[0024] FIG. 4 is an explanatory diagram showing a method for RTP transmission of general still picture data, and shows an example in which one piece of still picture data is divided into four RTP packets for transmission.

In the example of Fig. 4, the bit stream of still image data is divided into four, and the four bits after division Stream (1) 1 (4) is stored in the RTP payload (1) 1 (4) of each RTP packet in order.

[0025] The sequence number (SQ) in the RTP header (1) one (4) has the smallest value in the first RTP header (1), and the value in the subsequent RTP header (2) (4) is 1. It is incremented by one.

The time stamp (TS) in the RTP header (1) -1 (4) has the same value for the same still image.

In order to make it possible to recognize the breaks between images, "" is stored in the M bit of the RTP header (4) with the maximum sequence number (SQ) in the same still image, and RTP header (1) one ( "0" is stored in the M bit of 3).

[0026] Fig. 5 is an explanatory diagram showing a method for RTP transmission of general JPEG2000 still image data, and shows an example in which one still image data is divided into four RTP packets for transmission. Yes. The RTP transmission method in the first embodiment will be described later.

When transmitting JPEG2000 still image data, the main header of the code stream is important information, so the RTP payload of the first RTP packet, that is, the RTP payload (1) Stores config information (main header + tile part header).

Also, the bit stream of the encoded code stream is divided into three, and the three divided bit streams (1) and (3) are sequentially stored in the RTP payload (2)-(4) of the RTP packet. The

[0027] The sequence number (SQ) in the RTP header (1) one (4) has the smallest value in the first RTP header (1), and the value in the subsequent RTP header (2) (4) is 1. It is incremented by one.

In order to be able to recognize the breaks between images, "" is stored in the M bit of the RTP header (4) with the maximum sequence number (SQ) in the same still image, and RTP header (1) one ( "0" is stored in the M bit of 3). [0028] When JPEG2000 still image data is transmitted, as described above, the media distribution device RTP-packets the code stream and distributes a plurality of RTP packets. If the RTP payload (1) of the RTP packet cannot be received correctly, the still image cannot be played because there is no config information (main header + tile part header) even if the subsequent RTP packet can be received correctly. .

In the first embodiment, even when the RTP payload (1) of the first RTP packet cannot be correctly received, a still image can be reproduced as follows.

[0029] A table in which the correspondence between config_ID and config information (main header + tile part header) is recorded in advance is prepared. Table capacity S Table of media distribution device 1 Storage unit 14 and table of media reception device 2 Stored in the storage unit 22.

Specifically, the above table is created on the media distribution device 1 side, and the media distribution device 1 transmits the above table to the media reception device 2 using a protocol with delivery confirmation such as TCP, for example, Media distribution device 1 and media reception device 2 share the above table.

Alternatively, media distribution device 1 and media reception device 2 store the same table as a fixed value of the system in advance, so that media distribution device 1 and media reception device 2 share the above table.

FIG. 6 is an explanatory diagram showing a table in which the correspondence between config—ID and config information is recorded. In particular, the lower table is an example when there are three types of config information.

[0031] When the data dividing unit 11 of the media distribution device 1 receives the media data to be distributed, for example, the data dividing unit 11 divides the bit stream of the media data into three.

The RTP header construction unit 12 of the media distribution device 1 includes a time stamp (TS) indicating the display time, a sequence number (SQ) indicating the order of the RTP packets, and an M bit indicating the break between the images. Enter the header.

[0032] FIG. 8 is an explanatory diagram showing the method of Embodiment 1 when transmitting PEG2000 still image data by RTP, and includes the time stamp (TS), sequence number (SQ), and input bits inserted into the RTP header. These are the same as in the case of FIG.

FIG. 7 is an explanatory diagram showing the structure of the RTP packet distributed by the media distribution device 1. The

[0033] When the data division unit 11 divides the bit stream of the media data into three, the RTP payload construction unit 13 of the media distribution device 1 performs RTP payload of the leading RTP packet, that is, RTP as shown in FIG. Insert config information (main header + tile part header) into payload (1).

Also, the RTP payload construction unit 13 inserts the bitstream (1) 1 (3) divided by the data division unit 11 into the RTP payload (2)-(4) of the subsequent RTP packet in order.

[0034] The RTP payload header construction unit 15 of the media distribution device 1 refers to the table stored in the table storage unit 14 when the RTP payload construction unit 13 inserts the config information into the RTP payload (1). , Specify the config—ID corresponding to the config information. For example, if the config information is data (1), it is identified as config—ID power S “0”, and if the config information is data (2), it is identified as config—ID power.

[0035] After identifying the config-ID corresponding to the config information, the RTP payload header construction unit 15 inserts the config-ID into the RTP payload header (1) one (4) of the RTP packet. It goes without saying that the config-ID inserted in the RTP payload header (1) one (4) is the same value.

Here, config-ID is inserted in all RTP payload headers (1) (1) (4), but only in some RTP payload headers (for example, RTP payload header (1) (2)) It may be.

[0036] When four RTP packets are constructed by the RTP header construction unit 12, the RTP payload construction unit 13 and the RTP payload header construction unit 15, the packet delivery unit 16 of the media delivery device 1 Delivered to the media receiver 2 in order.

[0037] The packet receiver 21 of the media receiver 2 receives the four RTP packets distributed from the media distributor 1.

When the packet receiving unit 21 receives four RTP packets, the config information specifying unit 23 of the media receiver 2 extracts config_ID from the RTP payload header of any RTP packet.

The RTP payload header from which config_ID is extracted is an RTP payload that has been correctly received. As long as it is a load header, any RTP payload header can be used.For example, the RTP payload header with the highest priority set in advance must be set as the extraction target, and the RTP payload header must be received correctly. For example, the next highest priority RTP payload header should be set as the extraction target.

[0038] When the config information specifying unit 23 extracts the configuration ID from the RTP payload header of any RTP packet, the config information identifying unit 23 refers to the table stored in the table storage unit 22 and configures the config information corresponding to the config_ID. Is identified.

For example, if config-ID power S "0", the config information is identified as data (1), and if config-ID power S "l", config information is data (2). Identify.

Therefore, even if the RTP payload (1) of the RTP packet in which the config information is inserted cannot be received correctly, if another RTP packet is received correctly, the RTP payload header of the RTP packet will be displayed. You can get conf ig information from config_ID.

[0039] When the packet receiving unit 21 correctly receives the first RTP packet, the media data restoring unit 24 of the media receiving device 2 extracts config information from the RTP payload (1) of the RTP packet.

On the other hand, when the packet receiving unit 21 has not received the leading RTP packet correctly, the config information specified by the config information specifying unit 23 is acquired.

Here, when the packet receiver 21 is not able to receive the first RTP packet correctly, the packet receiver 21 can receive the first RTP packet correctly. Even if it is, you may get the config information from the config information identification part 23.

[0040] The media data restoration unit 24 extracts the RTP payload (2) (4) force of the subsequent RTP bucket received by the packet receiving unit 21 (1) one (3), and the above config information Use bitstream (1) one (3) force to restore media data.

When the media data restoration unit 24 restores the media data, the decoding unit 25 of the media receiver 2 converts the media data into image data.

In the image playback unit 26 of the media receiver 2, the decoding unit 25 converts the media data into image data. The image is displayed on the display 27 according to the image data.

[0041] As apparent from the above, according to the first embodiment, the media distribution device 1 identifies the config information required when the media data is restored. The config—ID is the RTP payload header of the RTP packet. (1) While inserting (4) and distributing each RTP packet, the media receiver 2 extracts the config_ID from the RTP payload header of any RTP packet, refers to the table, and configures the config — Since the config information corresponding to the ID is identified and the media information is restored from each bitstream using the config information, the Rf packet received with the config information is inserted. Even if it fails, the media data can be recovered from the bit stream inserted in the subsequent RTP packet.

[0042] Embodiment 2.

In Embodiment 1 above, the RTP payload constructing unit 13 of the media delivery device 1 has shown that the config information is inserted into the RTP payload (1) of the RTP packet. If the config information is acquired from the config information specifying unit 23, the RTP payload building unit 13 of the media delivery device 1 will not insert the config information into the RTP payload (1) of the RTP packet as shown in Fig. 9. Anyway.

As a result, the amount of transmission can be reduced by not delivering config information.

[0043] Embodiment 3.

In the first embodiment, the table storage unit 14 of the media distribution device 1 and the table storage unit 22 of the media reception device 2 are shown to store a common table. The table storage unit 22 of the media receiver 2 stores and updates the common table.

Specifically, as shown in FIG. 10, when the correspondence between three types of config—ID and config information is recorded in the table, the media distribution device 1 For example, using a protocol such as TCP with confirmation of delivery in the out-band, the pair of conf ig—ID “3” and config information “data (4)” is sent to the media receiver 2 as update information. I believe.

When the media receiving device 2 receives a set of config—ID “3” and config information “data (4)” from the media distribution device 1 as update information, the config—ID “3” and config information “data (4)” are received. Add the pair "to the table.

[0045] As shown in FIG. 11, when the correspondence between the three types of config-ID and config information is recorded on the tape, config-information "data (3) corresponding to config-ID" 2 " When "" is changed, the media distribution device 1 uses, for example, a protocol such as TCP that has been confirmed to be delivered out-of-band, and a set of config_ID "2" and config information "data (4)" as the update information. Sent to receiver 2

When the media receiver 2 receives a set of config—ID “2” and config information “data (4)” from the media delivery device 1 as update information, the config—ID “2” is already stored. config—Changes the config information corresponding to ID “2” from data (3) to data (4).

As apparent from the above, according to the third embodiment, when media receiving apparatus 2 receives table update information from media delivering apparatus 1, it updates the table according to the update information. Since it is configured, the config information can be appropriately updated according to the media data to be distributed.

[0047] Embodiment 4.

In Embodiment 1 above, the config information specifying unit 23 of the media receiver 2 extracts the config-ID from the RTP payload header of any RTP packet, and refers to the table stored in the table storage unit 22. As shown in FIG. 12, the packet receiver 21 of the media receiver 2 receives the config-ID “FF” (specific information) from the media distributor 1 as shown in FIG. When the identification information is received, the config information inserted in the RTP payload (1) of the RTP packet that does not refer to the table stored in the table storage unit 22 is used. (3) You can restore the media data from.

[0048] Specifically, this is as follows.

The config information specifying unit 23 of the media receiver 2 determines whether or not the config-ID inserted in the RTP payload header of any RTP packet is a specific value. That is, Determine whether config-ID is "FF".

[0049] If the config-ID is not "FF", the config information specifying unit 23 specifies the config information as in the first embodiment.

If the config-ID is "FF", the config information entered in the RTP payload (1) of the RTP packet that refers to the table stored in the table storage unit 22 is not used. To get.

[0050] The media data restoration unit 24 of the media receiver 2 receives the RTP payload (2) — (4) force and bit stream (1) 1 (3) of the subsequent RTP packet received by the packet receiver 21. Extract and use the config information acquired by the config information specifying unit 23 to restore the media data from the bitstream (1) one (3).

As it is evident in [0051] above, according to the fourth embodiment, the packet reception unit 21 of the media receiver 2 receives the _{con fig_ID} "FF" (specific identification information) from the media delivery device 1, Using the config information inserted in the RTP payload (1) of the RTP packet without referring to the table stored in the table storage unit 22, media data is restored from the bitstream (1) one (3). Thus, it is possible to restore the media data by using the config information not recorded in the table without updating the table stored in the table storage unit 22.

[0052] Embodiment 5.

In Embodiment 1 above, the config information specifying unit 23 of the media receiver 2 extracts the config-ID from the RTP payload header of any RTP packet, and refers to the table stored in the table storage unit 22. As shown in FIG. 13, when the packet receiving unit 21 of the media receiver 2 receives the difference information of the config information from the media distributor 1, as shown in FIG. Using the config information in the table stored in the table storage unit 22 and the difference information, media data may be restored from the bitstream (1) 1 (3).

Specifically, this is as follows.

The difference information of the config information is the difference information with respect to the config information (con fig information in the table) corresponding to the config-ID, and FIG. 14 is included in the difference information of the config information. Information is shown.

[0054] The difference information of the config information includes one config-ID and a change indicating the number of places where the config information (config information in the table) corresponding to the config-ID is changed. .

Also, in the difference information of the config information, as many as the number of changes, the offset indicating the change location, erace_length indicating the length of the data to be deleted, inse rt_length indicating the length of the data after the change, and the data after the change Contains data to indicate.

FIG. 15 shows a specific example in which config information is changed using the difference information description format shown in FIG.

Example (1) shows that config information with config — ID = 0x0 is changed in two places. Example (2) shows that the value of config information is changed and the byte length is changed at the same time.

As apparent from the above, according to the fifth embodiment, when the packet reception unit 21 of the media reception device 2 receives the difference information of the config information from the media distribution device 1, the table storage unit 22 Using the config information in the stored table and the difference information, the bit stream (1) one (3) force is also configured to restore the media data, so as in the first embodiment, config Even if reception of an RTP packet in which information is inserted fails, the bit stream force media data inserted in the subsequent RTP packet can be restored.

[0057] Also, since the config—ID is included in the difference information, the difference with the most similar config information can be transmitted among the config information recorded in the table. Thus, the transmission amount of the media distribution device 1 can be reduced.

[0058] Embodiment 6.

In Embodiment 1 above, there is no particular mention, but in the case of a transmission method using a protocol such as RTP with no delivery confirmation, any of the RTP packets into which the divided bitstream is inserted is used. If such reception fails, when decoding is performed using a correctly received bitstream, a decoding error may occur or an unnatural image may be displayed.

In the sixth embodiment, one of the RTP packets distributed from the media distribution device 1 is selected. Even if the RTP packet reception fails, the decoding error is prevented as follows.

FIG. 16 is an explanatory diagram showing an example of bit stream division, and a JP2K packet is a unit constituting a code stream. In the example of Fig. 16, the bit stream is divided so as to include one or more JP2K packets.

FIG. 17 is an explanatory diagram showing a process for compensating for the loss of some RTP packets. When a bit stream divided in units of JP2K packets is transmitted as shown in FIG. 16, that is, the media distribution device 1 has:! In this example, when the bitstream, which is JPEG2000 still image data, is divided into five and delivered, the RTP packet containing the bitstream (4) is missing during transmission.

[0060] As shown in FIG. 17, the media data restoration unit 24 of the media reception device 2 is a bit stream (4) ) Containing RTP packets cannot be correctly received, that is, when it is recognized that the RTP packet containing the sequence number (SQ) power bitstream (4) of the RTP header is missing, the config specified by the config information specifying unit 23 The bit stream (1) one (3) is combined after the information, and the end code (EOC) is combined after that.

The media data restoration unit 24 analyzes the combination result and restores the media data.

[0061] According to the sixth embodiment, since the bit stream (5) is lost, there is a slight deterioration in image quality. However, due to the nature of JPEG2000, in many cases, an image having a sufficient image quality is practically decoded. There is an effect.

[0062] Embodiment 7.

FIG. 18 shows an example of bit stream division in which the bit stream includes a fixed number of JP2K packets. In the example of FIG. 18, each bitstream (1) one (3) includes three JP2K packets.

Fig. 19 is an explanatory diagram showing the processing to compensate for the loss of some RTP packets. During transmission, when each bit stream is transmitted using a division method that includes a fixed number of JP2K packets as shown in Fig. 18, An example of missing RTP packet including bitstream (4) is doing.

[0063] As shown in Fig. 19, the media data restoration unit 24 of the media receiving device 2 is a power bitstream (4) that allows the packet receiving unit 21 to correctly receive the RTP packet including the bitstream (1) one (3). ) Containing RTP packets cannot be correctly received, that is, when it is recognized that the RTP packet containing the sequence number (SQ) power bitstream (4) of the RTP header is missing, the config specified by the config information specifying unit 23 Combine the bitstream (1) one (3) after the information.

[0064] Next, the media data restoration unit 24 adds null data (1-byte "0" data (0x00)) after the bit stream (3) by the number of JP2K packets included in the bit stream (4).

).

Next, the media data restoration unit 24 combines the bit stream (5) and the end code (E0C) after the null data.

[0065] According to the seventh embodiment, since the missing back bitstream (5) is also used, the image quality deterioration can be suppressed as compared with the sixth embodiment.

According to the JPEG2000 rules, supplementing JP2K packets with null packets is an error compensation method that eliminates inconsistencies as a bit stream.

Here, FIG. 20 is an explanatory diagram showing bucketing of the bit stream.

In the example of Figure 20, offset and include are included in the RTP payload header. offset and include are numerical values related to JP2K packets. In particular, offset indicates the cumulative number of JP 2K packets from the beginning, and include indicates the number of JP2K packets included in the bit stream of the RTP payload.

[0067] Bitstream (1) includes three JP2K packets, Bitstream (2) includes one JP2K packet, Bitstream (3) includes four JP2K packets, and Bitstream (4) Contains 5 JP2K packets, and bitstream (5) contains 3 JP2K packets.

Figure 21 shows the transmission of Figure 20 with missing RTP packets containing bitstream (4). Showing.

The number of JP2K packets included in the bitstream (4) is calculated from the offset and include values described in the correctly received RTP payload header.

In the example of FIG. 21, since the bit stream (4) is missing, the bit stream (4) is used by using the offset and include values described in the preceding and succeeding RTP payload headers. ) Calculate the number of JP2K packets X included.

X = ofiset5— offset 5— mclude3

Then, the number of JP2K packets X is supplemented with null packets. A null packet is 1 byte of 0x00. At this time, one JP2K packet is complemented with one null packet. Industrial applicability

[0069] As described above, the media transmission system according to the present invention improves the transmission efficiency by allowing the media data to be restored without discarding the correctly received bitstream even when the decoding parameters cannot be correctly received. Suitable for things that need to be raised.

Claims

The scope of the claims

[1] Data dividing means for dividing the bit stream of media data, and the bit stream divided by the data dividing means are inserted into the payload of each packet in order, and the decoding parameters of the media data are specified. A media distribution apparatus comprising: a packet construction unit that inserts identification information into a payload of each packet; and a packet distribution unit that distributes each packet in which the bit stream and the identification information are inserted by the packet construction unit.

[2] Packet receiving means for receiving each packet distributed from the media distribution device, table storage means for storing a table in which correspondences between identification information and decoding parameters are recorded, and received by the packet receiving means The identification information is extracted from the payload of any one of the packets, the decoding parameter specifying means for specifying the decoding parameter corresponding to the identification information with reference to the table stored in the table storage means, and the packet A bit stream is extracted from the payload of each packet received by the receiving means, and using the decoding parameter specified by the decoding parameter specifying means, the media data restoring means for restoring each bit stream also media data. Media receiving device provided.

[3] Divide the bit stream of the media data, insert the divided bit stream into the payload of each packet in order, and input the identification information that identifies the decoding parameter of the media data into the payload of each packet. If a media distribution device that distributes each packet and a table in which the correspondence between identification information and decoding parameters is recorded in advance and each packet distributed from the media distribution device is received, either The identification information is extracted from the payload of each packet, and the decoding parameters corresponding to the identification information are identified by referring to the above table, while the bit stream is extracted from the payload of each packet and the decoding parameters are used. And a media receiver that restores media data from each bitstream. A transmission system.

4. The media transmission system according to claim 3, wherein the media receiving device updates the table in accordance with the update information when receiving the update information of the table from the media distribution device.

[5] When the media receiving device receives the specific identification information and the decoding parameter from the media distribution device, it uses the decoding parameter without referring to the table to restore the media data from each bit stream. The media transmission system according to claim 3, wherein:

[6] When the media receiver receives the difference information of the media distribution device decoding parameter, the media receiver uses the decoding parameter recorded in the table and the difference information to restore the media data from each bit stream. 4. The media transmission system according to claim 3, wherein

[7] When the media receiving device fails to receive some of the packets distributed from the media distributing device, it extracts the bit stream from the payload of the correctly received packet and restores the media data. The media transmission system according to claim 3, wherein:

[8] When combining media from the first bit stream to the last bit stream, the media receiver, if there is a packet that has failed to be received, is sent from the first bit stream to the packet immediately before the packet that has failed to be received. 8. The media transmission system according to claim 7, wherein a bit stream inserted in the payload is combined.

[9] When combining media from the first bit stream to the last bit stream, the media receiver, if there is a packet that failed to be received, substitutes null data instead of the bit stream inserted in the packet that failed to be received. 8. The media transmission system according to claim 7, wherein the media transmission system is combined.

10. The media transmission system according to claim 9, wherein the media reception device combines null data by a fixed number set in advance.

[11] The media receiver refers to the description contents of the payload of the correctly received packet, calculates the number of null data to be combined instead of the bit stream, and combines the null data by that number. The media transmission system according to claim 9.