[MPlayer-dev-eng] [PATCH] -vf fixpts=use_timer

[Reimar Döffinger]

On Wed, Jul 21, 2010 at 06:11:11PM +0200, Dan Oscarsson wrote:
> As I would also like to have monotonous pts values very much
> I have been testing enabling reordering for the nocorrect-pts case and
> for several .avi files which get
> [ffodivx] vfm: ffmpeg (FFmpeg MPEG-4) as decoder, I see that the first
> video frame is "delayed" (i.e. mpvdec->decode returns NULL).
> When using -demuxer lavf which sets correct_pts, the pts for first video
> frame is 0.041708 while without it, the pts is 0.000000.
> 
> Now I wonder, what is the correct pts of the first frame? Is it 0.000
> which is what I could expect from a .avi file, or is the first frame in
> the file is discarded so the first frame has pts 0.041708?
> 
> Not every .avi (mpeg-4) file "delays" first frame. Is the above because
> of a B-frame so no frame is discarded, just delayed?

The frame is only "delayed" in the sense that you need to put multiple
packets in the decoder before you get one out.
This (is not supposed to) have any effect on the pts values themselves,
only their order. And since minimum and maximum do not change with order,
the start time should not change.
I suspect that MPlayer simply always starts with 0 when decoding with
-nocorrect-pts, but I don't know for sure.