[Libav-user] PTS values and writing encoded audio and video frames ?

ashika umanga umanga.forums at gmail.com
Thu Apr 12 08:28:14 CEST 2012


When I encode an OGG file with Theora+Speex , my video length is longer
than the audio playback.
Anytips on this ?

On Thu, Apr 12, 2012 at 2:51 PM, Gagandeep Bawa <gagandeep.bawa at ironroad.com
> wrote:

> Hi,
>
> These PTS and DTS used for sync between audio and video data while
> encoding and presentation. Check below link for more details.
>
> *http://dranger.com/ffmpeg/tutorial05.html*
>
> Thanks,
> Gagan
>
> On Thu, Apr 12, 2012 at 11:14 AM, ashika umanga <umanga.forums at gmail.com>wrote:
>
>> Greetings all,
>>
>> I am writing a wrapper class for video/audio encoding by following the
>> "muxing.c".
>> http://ffmpeg.org/doxygen/trunk/muxing_8c-source.html
>>
>> I see in the example that before writing frames to the file ,is checks
>> whether the PTS value of audiostream is
>> lesser than that of videostream.
>>
>> code snippet:
>>
>>  if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {
>>             write_audio_frame(oc, audio_st);
>>         } else {
>>             write_video_frame(oc, video_st);
>>             picture->pts++;
>>         }
>>
>> Can someone explain why this test is done? Whats the connection between
>> PTS values ?
>>
>>
>>
>> _______________________________________________
>> Libav-user mailing list
>> Libav-user at ffmpeg.org
>> http://ffmpeg.org/mailman/listinfo/libav-user
>>
>>
>
>
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/libav-user
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ffmpeg.org/pipermail/libav-user/attachments/20120412/496d047b/attachment.html>


More information about the Libav-user mailing list