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

[Michel Bardiaux]

Martin Boehme wrote:
> Keith Mok wrote:
> 
>> But some encoder  create movie file, with several seconds of movie 
>> data, then video data.
> 
> 
> I assume you mean "audio", not "video"?
> 
>> 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?
> 
> 
> Yes, it's going to require some memory... but what else could you do?

av_seek_frame and av_read_frame should work independently on each stream.

> 
> Martin
> 
> P.S. Please don't top-post...
> 
>> M?ns Rullg?rd wrote:
>>
>>> Keith Mok <ek9852 at yahoo.com.hk> writes:
>>>
>>>> Hi
>>>>
>>>> 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.
> 
> 


-- 
Michel Bardiaux
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