[FFmpeg-devel] first_dts set to RELATIVE_TS_BASE in vorbis audio

Don Moir donmoir at comcast.net
Tue Apr 10 18:18:30 CEST 2012

----- Original Message ----- 
From: "Don Moir" <donmoir at comcast.net>
To: "FFmpeg development discussions and patches" <ffmpeg-devel at ffmpeg.org>
Sent: Tuesday, April 10, 2012 11:43 AM
Subject: Re: [FFmpeg-devel] first_dts set to RELATIVE_TS_BASE in vorbis 

> On Mon, Apr 09, 2012 at 07:57:17AM -0400, Don Moir wrote:
>>> In recent builds I now see that the AVStream.first_dts is set to 
>>> RELATIVE_TS_BASE which is 0x7ffeffffffffffff.
>>> RELATIVE_TS_BASE is defined in libavformat\utils.c
>>> Not sure what all this effects, but I am seeing it in ogg files with 
>>> vorbis audio for the audio stream.
>>> Previously, the first_dts value was always reliable in that it was set 
>>> correctly or it contained AV_NOPTS_VALUE.
>>> Is this a bug or what does it mean ?
>>do you have a testcase ?
>>i mean a file + command line that shows a wrong output or something ?
>>its easyier to look into this when we look at the same case
>>instead of picking a random file and random options that certainly
>>would be different from what you used
> I was hoping someone could answer why this was changed.
> It looks like all my ogg files have this problem in the audio stream only, 
> but it may be effecting other formats. Mostly it looks ok with other 
> formats but not sure.
> The value in first_dts may be exactly RELATIVE_TS_BASE as in the following 
> sample or RELATIVE_TS_BASE minus some unknown.
> http://sms.pangolin.com/temp/bad_first_dts_in_audio_stream.ogv

The last known good to me is git-e01f478 but there may be a more recent 
version that was good.

The failing version that i first discovered it is git-41a097a but it may 
fail in earlier version. git-6bfb304 is still a problem. 

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