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

[ashika umanga]

I mean, I used "muxing.c" to generate the OGG file.That means both audio
and video stream should have the same length,isnt it ?



On Thu, Apr 12, 2012 at 3:31 PM, Gagandeep Bawa <gagandeep.bawa at ironroad.com
> wrote:

> You have to check your video frame rate. I worked on IPhone recorded
> videos files and it varies between 15 to 30.
>
>
> On Thu, Apr 12, 2012 at 11:58 AM, ashika umanga <umanga.forums at gmail.com>wrote:
>
>> 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 ?
>>>>
>>>>
>>>>
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>>>>
>>>
>>>
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>>
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>
>
> --
>
> Thanks & Regards,
> Gagandeep, Tech Lead Mobility
>
> +91- 7307470044
>
>
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