[FFmpeg-devel] [patch 3/3] Make timing calculations less dependant on start_time being defined.

Benoit Fouet benoit.fouet
Mon Aug 27 11:02:48 CEST 2007


Michael Niedermayer wrote:
> Hi
>
> On Sat, Aug 25, 2007 at 08:45:50AM +1000, Neil Brown wrote:
>   
>> On Friday August 24, michaelni at gmx.at wrote:
>>     
>>>> I'm having a hard time understanding the point of some of (well... all
>>>> of) the code in update_initial_timestamps.
>>>>         
>>> its very simple, av_find_stream_info() analyses a input file/stream and
>>> buffers all packets which it had to read (so that theres no need to seek
>>> back after av_find_stream_info() which with pipes would be impossible)
>>>
>>> update_initial_timestamps() updates the timestamps of these buffered
>>> packets in the case that the packets had no timestamp (that is libavformat
>>> used the framerate / AVPacket.duration to set timestamps starting from a
>>> arbitrary (=0) timestamt)
>>>       
>> Ahhhh... I get it now.  All the time stamps are being offset by
>>    dts - st->cur_dts
>>
>> That makes sense.  Thanks.
>>
>>     
>>> the first packet with a timestamp gets put in the buffer after 
>>> update_initial_timestamps() is called thus if theres nothing in the buffer
>>> the code to set start_time fails ...
>>> solution seems to be to pass pkt->pts in addition to dts into
>>> update_initial_timestamps() and then add an additional check to use that
>>> if no packet in the buffer had a pts value
>>>       
>> So this patch maybe (which also appears to fix my problem).
>>     
>
> patch looks ok
>
> [...]
>   

Neil, please attach your patches to your mails and generate your diffs
so that the patches can be applied with patch -p0 or -p1, thanks.

also, libav tests reference file needs an update...
see attached patch

-- 
Ben
Purple Labs S.A.
www.purplelabs.com
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