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Audio and video synchronous processing method and device

A technology of audio and video synchronization and video frame, which is applied in image communication, selective content distribution, electrical components, etc., and can solve problems such as lip synchronization

Active Publication Date: 2018-07-03
SANECHIPS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the above technical problems, the embodiments of the present invention expect to provide a method and device for synchronizing audio and video, which can accurately reconstruct the system clock at the decoding end that is consistent with the encoding end, thereby providing an accurate clock reference for audio and video synchronization. Then through audio and video synchronization processing to solve the lip sync problem during video playback

Method used

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  • Audio and video synchronous processing method and device
  • Audio and video synchronous processing method and device
  • Audio and video synchronous processing method and device

Examples

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Embodiment 1

[0089] see figure 2 , which shows a method for audio and video synchronization processing provided by an embodiment of the present invention, the method comprising:

[0090] S101. Compare the current program clock reference PCR value with the current system clock STC value to obtain a first comparison result.

[0091] see image 3 , specifically, step S101 includes steps S1011 to S1014:

[0092] S1011. Load the first PCR value or the reloaded PCR value into the local STC counter as an initial count value.

[0093] It should be noted that when the first PCR arrives or the PCR needs to be reloaded, the current PCR value is loaded into the local STC counter as the initial count value. The local STC counter is also divided into STC_base and STC_extension to count separately; among them, STC_base is the basic value of STC, which is the high 33bit of STC, and the initial value is PCR_base, and then counts up under the drive of 90kHz clock, mainly used for PTS and DTS Compare to...

Embodiment 2

[0149] see Figure 9 , which shows an audio-video synchronization processing device 9 provided by an embodiment of the present invention, the device includes: a comparison module 901 and an adjustment module 902; wherein,

[0150] The comparison module 901 is configured to compare the current program clock reference PCR value with the current system clock STC value to obtain a first comparison result;

[0151] The adjustment module 902 is configured to rebuild the system clock STC by adjusting the current STC count step size when the first comparison result does not meet the preset judgment condition;

[0152] The comparison module 901 is further configured to compare the absolute value of the difference between the STC base value STC_base in the reconstructed system clock STC and the display time tag PTS value with a preset time interval to obtain a second comparison result ; Wherein, the preset time interval is M times the time between audio or video frames, and M is greate...

Embodiment 3

[0179] against Figure 9 device shown, see Figure 11 , which shows the hardware implementation device involved in the reconstruction of the system clock and the audio and video synchronization processing provided by the embodiment of the present invention. The hardware implementation device may specifically include three parts: CPU, demultiplexer demux and decoder decoder .

[0180] The demultiplexer demux is divided into a ts_ph_get module and a PCR_recovery module, wherein the ts_ph_get module performs packet header analysis, extracts PCR_flag and PCR values ​​from the adaptive area of ​​the MPEG2-TS stream, and sends them to the PCR_recovery module to rebuild the system clock.

[0181] The PCR_recovery module saves the PCR value. Specifically, when the local STC counter deviates from the local system clock, the STC step can be adjusted by the CPU to adjust the STC counter so that it is basically consistent with the current PCR. The PCR_recovery module sends the pcr_inter...

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Abstract

The embodiments of the invention disclose an audio and video synchronous processing method. The method includes the following steps that: a current program clock reference (PCR) value is compared witha current system time clock (STC) value, so that a first comparison result is obtained; when the first comparison result does not satisfy a preset judgment condition, a STC count step size is adjusted, so that a STC can be reconstructed; the absolute value of the difference value of the STC base value STC_base in the STC and a presentation time stamp (PTS) value is compared with a preset time interval, so that a second comparison result can be obtained, wherein the preset time interval is M times of audio or video inter-frame time, wherein M is greater than 0 and is smaller than 1; and audioor video playing speed is adjusted according to the second comparison result. The embodiments of the invention also disclose an audio and video synchronous processing device.

Description

technical field [0001] The invention relates to the field of digital television, in particular to a method and device for synchronous processing of audio and video. Background technique [0002] There is a system clock (STC, System Time Clock) with a frequency of 27MHz in the encoder, which is used to generate the correct display time stamp (PTS, Presentation Time Stamp) and decoding time stamp (DTS, Decode Time Stamp) of audio and video, It can also be used to indicate the instantaneous sampling value of the system clock itself. The sending end inserts the instantaneous sampling value of the system clock into the PCR field of the MPEG-2 TS stream when the Program Clock Reference (PCR, Program Clock Reference) field leaves the multiplexer, and the receiving end can recover and encode it by extracting the PCR field The 27MHz system clock synchronized by the device is used, and then the PTS and DTS in the PES stream are used to realize the synchronization of audio and video. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N21/242H04N21/43H04N21/8547
CPCH04N21/242H04N21/4305H04N21/4307H04N21/8547H04N21/43
Inventor 郭荣
Owner SANECHIPS TECH CO LTD