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

Don Moir donmoir at comcast.net
Tue Apr 10 17:43:11 CEST 2012

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.


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