CN114189737B - Digital television rapid channel switching method and digital television - Google Patents
Digital television rapid channel switching method and digital television Download PDFInfo
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- CN114189737B CN114189737B CN202111478310.0A CN202111478310A CN114189737B CN 114189737 B CN114189737 B CN 114189737B CN 202111478310 A CN202111478310 A CN 202111478310A CN 114189737 B CN114189737 B CN 114189737B
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- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000009877 rendering Methods 0.000 claims abstract description 37
- 230000001360 synchronised effect Effects 0.000 claims abstract description 21
- 230000000694 effects Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
- H04N21/438—Interfacing the downstream path of the transmission network originating from a server, e.g. retrieving encoded video stream packets from an IP network
- H04N21/4383—Accessing a communication channel
- H04N21/4384—Accessing a communication channel involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
- H04N21/4302—Content synchronisation processes, e.g. decoder synchronisation
- H04N21/4307—Synchronising the rendering of multiple content streams or additional data on devices, e.g. synchronisation of audio on a mobile phone with the video output on the TV screen
- H04N21/43074—Synchronising the rendering of multiple content streams or additional data on devices, e.g. synchronisation of audio on a mobile phone with the video output on the TV screen of additional data with content streams on the same device, e.g. of EPG data or interactive icon with a TV program
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
- H04N21/85—Assembly of content; Generation of multimedia applications
- H04N21/854—Content authoring
- H04N21/8547—Content authoring involving timestamps for synchronizing content
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Computer Security & Cryptography (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
- Television Signal Processing For Recording (AREA)
Abstract
The invention provides a digital television rapid channel switching method and a digital television, wherein the method comprises the following steps: after receiving the channel switching instruction, respectively decoding the video and the audio of the new channel, immediately rendering the decoded video, judging whether the audio and the video are synchronous, and if the audio and the video are synchronous, rendering the audio and the video at a normal speed; if the audio and video are not synchronous, the video/audio rendering speed is reduced until the audio and video are synchronous, and then the audio and video are rendered at a normal speed. By adopting the technical scheme of the invention, the table cutting speed can be improved, and the user experience is improved.
Description
Technical Field
The invention relates to the field of digital televisions, in particular to a digital television rapid channel switching method and a digital television.
Background
Digital television has entered into thousands of households and contributes to people to a rich and colorful high-definition entertainment program. Because the code stream of the digital television is sent to the receiving end after being compressed, the code stream can be rendered after being decoded at the receiving end.
As shown in fig. 1 and 2, the current digital television station switching process is as follows:
1. the sending end inserts time stamp information into the code stream through PCR, and the receiving end receives the PCR recovery local clock STC;
2. when a transmitting end transmits an audio frame and a video frame, adding a frame play time stamp VPTSn and APTSn;
3. The receiving end receives the audio frame and the video frame, decodes the audio frame and the video frame, compares the decoded audio frame and the decoded video frame with a local STC clock, renders the audio and the video if VPTSn and APTSn are smaller than STC, and continues waiting if not.
In the prior art, the time consumption of cutting a table mainly comprises two parts:
filtering the first I frame from the code stream after the channel cutting, wherein the time consumption is represented by T1;
After the decoder decodes the first frame video, the first frame video is rendered after the STC clock is reached, and the time consumption is represented by T2;
Total consumption time of cutting table T:
T = T1 + T2；
For cost reasons, to make full use of the channel bandwidth, existing DVB operator networks all increase the video compression rate as much as possible, which leads to two problems:
the I-frame interval is relatively long. This results in T1 being relatively large;
In order to prevent bandwidth shortage caused by video rate jitter, video frames are pushed in advance as much as possible, i.e. PTS is far larger than PCR. This results in T2 being relatively large.
This results in a relatively long live cut time for the digital television, and a very poor user experience.
Disclosure of Invention
The invention aims to provide a digital television rapid channel switching method and a digital television aiming at the defect of long channel switching time of the digital television live broadcast in the prior art.
The embodiment of the invention provides a rapid channel cutting method for a digital television, which comprises the following steps:
After receiving the channel switching instruction, respectively decoding the video and the audio of the new channel, immediately rendering the decoded video, judging whether the audio and the video are synchronous,
If the audio and video are synchronous, rendering the audio and video at a normal speed;
If the audio and video are not synchronous, the video/audio rendering speed is reduced until the audio and video are synchronous, and then the audio and video are rendered at a normal speed.
In the embodiment of the invention, if the video is earlier than the audio, the video rendering speed is reduced: if the audio is earlier than the video, the audio rendering speed is reduced.
In the embodiment of the invention, before audio and video synchronization, only video frames are played, and audio frames are not played; after the audio and video synchronization, the audio and video is synchronously played.
In the embodiment of the invention, the difference value between the current video frame playing time stamp and the audio frame playing time stamp is judged, if the difference value between the current video frame playing time stamp and the audio frame playing time stamp is larger than a set value, only the video is played, the audio is not played, and otherwise, the audio and the video are synchronously played.
In the embodiment of the invention, the manner of reducing the video/audio rendering speed is as follows:
Before audio and video synchronization, the rendering time of each video frame/audio frame is dynamically adjusted according to the difference value between the current video frame playing time stamp and the audio frame playing time stamp.
In the embodiment of the invention, the larger the difference value between the current video frame playing time stamp and the audio frame playing time stamp is, the longer the rendering time of the current video frame/audio frame is, the smaller the difference value between the current video frame playing time stamp and the audio frame playing time stamp is, and the shorter the rendering time of the current video frame/audio frame is.
In the embodiment of the invention, the manner of reducing the video/audio rendering speed is as follows:
Before audio-video synchronization, the fixed rendering time length of each video frame/audio frame is increased.
In the embodiment of the invention, whether the audio and video are synchronous is judged according to whether the current video frame playing time stamp is the same as the audio frame playing time stamp.
In the embodiment of the invention, a digital television is also provided, and the digital television adopts the rapid channel switching method of the digital television when switching channels.
Compared with the prior art, the digital television rapid channel cutting method provided by the invention has the advantages that after the channel cutting instruction is received, the audio frames and the video frames are respectively decoded, and as the audio frames are usually sent after the video frames, the decoded video is immediately rendered and then subjected to audio-video synchronization, and before the audio-video synchronization, the video rendering speed is reduced until the audio-video synchronization is carried out, and the normal video rendering speed is recovered, so that the channel cutting speed is increased, and the user experience effect is provided.
Drawings
Fig. 1 is a schematic diagram of prior art digital television program transmission and reception.
Fig. 2 is a flow chart of a prior art digital television zapping method.
Fig. 3 is a flowchart of a digital television channel switching method according to an embodiment of the present invention.
Detailed Description
As shown in fig. 3, in an embodiment of the present invention, a method for fast switching between digital televisions is provided, which includes steps S1 to S5. The following description will be given separately.
Step S1: after receiving the channel switching instruction, respectively decoding the video and the audio of the new channel, and immediately rendering the decoded video.
In the digital television code stream, the audio stream and the video stream are usually transmitted separately. Because the video stream occupies a large bandwidth, in order to prevent the bandwidth shortage caused by video code rate jitter, video frames are pushed in advance as much as possible, so that the situation of asynchronous audio and video may exist. In another case, if the transmission bandwidth becomes problematic, resulting in slow video streaming, it is possible that audio feeds arrive, resulting in an asynchronous audio-video. In the prior art, the audio and video are synchronously rendered after waiting for synchronization of the audio and video, so that a user can feel long channel changing response time. In the embodiment of the invention, synchronization is not needed, and the first video frame is immediately rendered after being decoded, so that a user feels fast channel changing.
Step S2: and judging whether the audio and video are synchronous or not.
Note that, when the program is rendered, if the audio and video are not synchronized, the viewer experience will be degraded, so in the television program, the audio and video are generally rendered synchronously. In the video stream, each video includes a video frame playing time stamp VPTS, and each audio includes an audio frame playing time stamp APTS, and time synchronization is performed through the two time stamps.
In this step, whether the audio and video are synchronized is determined according to whether the current video frame play time stamp VPTS is the same as the audio frame play time stamp APTS. If the current video frame playing time stamp VPTS is the same as the audio frame playing time stamp APTS, the audio and video synchronization is described; if the current video frame playing time stamp VPTS is later than the audio frame playing time stamp APTS, the video is indicated to be earlier than the audio; if the current video frame play time stamp VPTS is earlier than the audio frame play time stamp APTS, then this indicates that the audio is earlier than the video.
Step S3: if the audio and video are synchronous, rendering the audio and video at a normal speed and playing the audio and video.
Step S4: if the video is earlier than the audio, the video rendering speed is reduced until the audio and the video are synchronous, and then the audio and the video are rendered at a normal speed.
Step S5: if the audio is earlier than the video, the audio rendering speed is reduced until the audio and the video are synchronous, and then the audio and the video are rendered at a normal speed.
In the embodiment of the invention, in order to prevent the influence of asynchronous rendering of audio and video on the experience of audiences before audio synchronization, only video frames are played and audio frames are not played before audio and video synchronization; after the audio and video are synchronized, the audio and video are synchronously played. Further, the difference between the current video frame playing time stamp and the audio frame playing time stamp can be judged, if the difference between the current video frame playing time stamp and the audio frame playing time stamp is too large and is larger than a set value, the difference between the audio and the video is obvious, only the video is played, and the audio is not played, otherwise, if the difference between the current video frame playing time stamp and the audio frame playing time stamp is not large, the audience probably feels that the difference is not large, and the audio and the video are simultaneously played.
In the embodiment of the invention, the reduction of the video/audio rendering speed can be realized in two modes.
The first is a static adjustment manner, that is, before audio-video synchronization, the fixed rendering time length of each video frame/audio frame is increased, so that the rendering speed of the party with the earlier playing time stamp in the video and the audio is reduced until the two are synchronized. For example, each frame of video is normally rendered for 40ms, and the display is increased by 10ms when adjusted, namely, the display becomes 20fps; after the mode is switched off, due to the effect of visual retention, a user cannot easily perceive slow playing of the picture, but the adjustment time is long, and the audio and video synchronization is slow.
The second mode is a dynamic adjustment mode, namely, before audio and video synchronization, the rendering time of each video frame/audio frame is dynamically adjusted according to the difference value between the current video frame playing time stamp and the audio frame playing time stamp. Specifically, the larger the difference between the current video frame playing time stamp and the audio frame playing time stamp is, the longer the rendering time of the current video frame is, the smaller the difference between the current video frame playing time stamp and the audio frame playing time stamp is, and the shorter the rendering time of the current video frame is. The method can realize quick synchronization of audio and video, but has obvious slow playing effect of video pictures after the platform is cut.
In the embodiment of the invention, a digital television is also provided, and the digital television adopts the rapid channel switching method of the digital television when switching channels.
In summary, according to the rapid channel switching method for the digital television, after receiving the channel switching instruction, the audio frames and the video frames are decoded respectively, and as the audio frames are usually sent after the video frames, the decoded video is immediately rendered, then audio and video synchronization is performed, and before the audio and video synchronization, the video rendering speed is reduced until the audio and video synchronization is performed, and the normal video rendering speed is restored, so that the channel switching speed is increased, and the user experience effect is provided.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (2)
1. The rapid channel cutting method for the digital television is characterized by comprising the following steps of:
after receiving the channel switching instruction, respectively decoding the video and the audio of the new channel, immediately rendering the decoded video, judging whether the audio and the video are synchronous according to whether the current video frame playing time stamp is the same as the audio frame playing time stamp,
If the audio and video are synchronous, rendering the audio and video at a normal speed;
If the audio and video are not synchronous, the video/audio rendering speed is reduced until the audio and video are synchronous, and then the audio and video are rendered at a normal speed; if the video is earlier than the audio, reducing the video rendering speed; if the audio is earlier than the video, reducing the audio rendering speed;
Before audio and video synchronization, dynamically adjusting the rendering time of each video frame/audio frame according to the difference value of the current video frame playing time stamp and the audio frame playing time stamp, wherein the larger the difference value of the current video frame playing time stamp and the audio frame playing time stamp is, the longer the rendering time of the current video frame/audio frame is, the smaller the difference value of the current video frame playing time stamp and the audio frame playing time stamp is, and the shorter the rendering time of the current video frame/audio frame is;
Before audio and video synchronization, only playing video frames and not playing audio frames; after the audio and video synchronization, the audio and video is synchronously played.
2. The method for fast switching digital television according to claim 1, wherein the difference between the current video frame playing time stamp and the audio frame playing time stamp is determined, if the difference between the current video frame playing time stamp and the audio frame playing time stamp is greater than a set value, only video is played, audio is not played, otherwise audio and video are synchronously played.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111478310.0A CN114189737B (en) | 2021-12-06 | 2021-12-06 | Digital television rapid channel switching method and digital television |
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| CN202111478310.0A CN114189737B (en) | 2021-12-06 | 2021-12-06 | Digital television rapid channel switching method and digital television |
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| CN114189737A CN114189737A (en) | 2022-03-15 |
| CN114189737B true CN114189737B (en) | 2024-08-06 |
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| CN116017012B (en) * | 2022-11-28 | 2024-09-20 | 深圳创维－Rgb电子有限公司 | Multi-screen synchronization method, device, display equipment and computer readable storage medium |
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| EP2048890A1 (en) * | 2007-10-11 | 2009-04-15 | Thomson Licensing | System and method for an early start of audio-video rendering |
| KR101678388B1 (en) * | 2014-02-06 | 2016-12-06 | 엔트릭스 주식회사 | Video processing method be considered latency, apparatus and cloud streaming service system therefor |
| JP5708866B1 (en) * | 2014-04-10 | 2015-04-30 | ソニー株式会社 | Transmitting apparatus, transmitting method, receiving apparatus, and receiving method |
| CN104837052B (en) * | 2014-06-10 | 2018-09-04 | 腾讯科技（北京）有限公司 | Play the method and device of multi-medium data |
| CN109963184B (en) * | 2017-12-14 | 2022-04-29 | 阿里巴巴集团控股有限公司 | Audio and video network playing method and device and electronic equipment |
| CN113382300B (en) * | 2021-06-08 | 2023-03-21 | 三星电子（中国）研发中心 | Audio and video playing method and device |
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