[FFmpeg-devel] [PATCH] avcodec/mpegvideo: remove redundant workaround to recalculate last nonzero coefficient

[Michael Niedermayer]

On Wed, Aug 28, 2024 at 02:14:33PM +0200, Ramiro Polla wrote:
> On Thu, Aug 22, 2024 at 1:24 AM Ramiro Polla <ramiro.polla at gmail.com> wrote:
> > The x86 optimized dct_quantize only calculates the last nonzero
> > coefficient correctly if the zigzag scan order is used. For the
> > alternate scan order, this value is incorrect.
> >
> > To work around this, the dct_unquantize functions process the entire
> > block if the alternate scan order is used.
> >
> > But a second workaround (bb198e198ab) was added that recalculates the
> > last nonzero coefficient after dct_quantize is called if the alternate
> > scan order is used.
> >
> > This commit removes the first workaround, which became redundant.
> > ---
> >  libavcodec/mpegvideo.c     | 9 +++------
> >  libavcodec/x86/mpegvideo.c | 6 ++----
> >  2 files changed, 5 insertions(+), 10 deletions(-)
> 
> Michael, could you please check if my analysis and the changes are correct?

If you tested it and it works it has to be correct.
This would result in significant errors if it was wrong

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The misfortune of the wise is better than the prosperity of the fool.
-- Epicurus
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
URL: <https://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20240829/65a8071f/attachment.sig>