[Ffmpeg-devel] How to retrieve audio or video stream at same timestamp using av_read_frame

Keith Mok ek9852
Sun May 22 15:46:24 CEST 2005


But some encoder  create movie file, with several seconds of movie data, 
then video data.
If buffer excess data, will require a lot of memory specially if you 
need to buffer several seconds of the video data in a frame rate of 30 fps.
Any comment?


M?ns Rullg?rd wrote:

>Keith Mok <ek9852 at yahoo.com.hk> writes:
>>When I use av_read_frame, I cannot select whether I want audio stream
>>or video stream data.
>>It will determine automatically.
>>And application need to check the stream type after output.
>>For some movie files, the video data may not be followed immediately
>>by the audio data. It may hold few tens seconds of video data followed
>>by audio data.
>>During real time playback of a movie file, I want to demux the audio
>>portion data and video portion data at about the same timestamp. The
>>only way I can get it is to create two seperate instances of
>>AVFormatContext on the same movie file. This can waste some
>>resource. Any better idea ?
>The usual solution is to buffer whatever excess audio or video frames
>you get until it's time to decode them.

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