[FFmpeg-devel] FATE wmv8_x8intra.wmv sample?

[Reimar Döffinger]

On Sun, Apr 08, 2012 at 07:05:23PM +0200, Reimar Döffinger wrote:
> On Fri, Jan 06, 2012 at 03:06:53AM +0100, Michael Niedermayer wrote:
> > On Thu, Jan 05, 2012 at 05:02:21PM +0100, Reimar Döffinger wrote:
> > > Hello,
> > > it seems we have a file wmv8_x8intra.wmv in fate-suite but no test runs
> > > it?
> > > The issue with that is that the MPlayer regression tests use it and the
> > > result changed.
> > > Since FFmpeg doesn't seem to test it I now have no idea what to do about
> > > that (result looks fine as far as I can tell, but that does not have to
> > > mean much).
> > > Any suggestions?
> > 
> > what commit caused the change ?
> 
> This was caused by this commit:
> 
> commit 8400b126acb153329c418433c377d96afd1d1e02
> Author: Mans Rullgard <mans at mansr.com>
> Date:   Sun Dec 18 20:41:42 2011 +0000
> 
>     avcodec: deprecate AVFrame.age
>     
>     This was intended as an optimisation for skipped blocks in MPEG2
>     P-frames and never used elsewhere.  Removing this "optimisation"
>     speeds up MPEG2 decoding by 1-2% (ARM Cortex-A9).
>     
>     Signed-off-by: Mans Rullgard <mans at mansr.com>
> 
> 
> I'd say it obviously must be buggy, because according to the commit message
> it should not be possible for it to change any results.
> It contains far too many non-trivial changes for me to guess what exactly
> is wrong, so if someone could review it that would be welcome.

Not the cause, but it seems at least below code no makes that much
sense after that commit:
mpegvideo.c:1511
                if (s->avctx->debug & FF_DEBUG_SKIP) {
                    int count = s->mbskip_table[x + y * s->mb_stride];
                    if (count > 9)
                        count = 9;
                    av_log(s->avctx, AV_LOG_DEBUG, "%1d", count);
                }
mbskip_table can only be 0 or 1 now, so calling it count and clamping to
9 is at least pointless.