Changeset 6fe8556a in ffmpeg

Timestamp:

Oct 31, 2022, 10:24:29 PM (2 years ago)

Author:

Peter Ross <pross@xvid.org>

Branches:

master

Children:

16af424b

Parents:

b0c1f248

Message:

avcodec/svq1: fix interframe mean VLC symbols

Fixes ticket #128.

The SVQ1 interframe mean VLC symbols -128 and 128 are incorrectly swapped
in our SVQ1 implementation, resulting in visible artifacts for some videos.
This patch unswaps the order of these two symbols.

The most noticable example of the artiacts caused by this error can be observed in
​https://trac.ffmpeg.org/attachment/ticket/128/svq1_set.7z '352_288_k_50.mov'.
The artifacts are not observed when using the reference decoder
(QuickTime 7.7.9 x86 binary).

As a result of this patch, the reference data for the fate-svq1 test
($SAMPLES/svq1/marymary-shackles.mov) must be modified. For this file, our
decoder output is now bitwise identical to the reference decoder. I have
tested patch with various other samples and they are all now bitwise identical.

(No files)