From: Peter Ross <pross@xvid.org>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH] avcodec/svq1: fix interframe mean VLC symbols
Date: Mon, 17 Oct 2022 20:33:28 +1100
Message-ID: <Y00haAojX9+MMaDI@fec08ea42f77375e1b3adc0238ae6674> (raw)
In-Reply-To: <AS8P250MB0744D2D27FC09CE83C1B24318F299@AS8P250MB0744.EURP250.PROD.OUTLOOK.COM>
[-- Attachment #1.1: Type: text/plain, Size: 1430 bytes --]
On Mon, Oct 17, 2022 at 05:04:29AM +0200, Andreas Rheinhardt wrote:
> Peter Ross:
> > 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.
>
> Seems like this is not the only test whose reference needs to be
> updated. There are also the fate-vsynth%-svq1 tests.
Right, the encoder. This change will cause previous videos created by the FFmpeg
encoder to playback *with* artifacts in newer builds of FFmpeg with this patch
applied. There is not much we can do about this, since there isn't place for a
version string in the SVQ3 bitstream (unlike MPEG-4 etc).
-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]
[-- Attachment #2: Type: text/plain, Size: 251 bytes --]
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
next prev parent reply other threads:[~2022-10-17 9:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-17 2:36 Peter Ross
2022-10-17 3:04 ` Andreas Rheinhardt
2022-10-17 9:33 ` Peter Ross [this message]
2022-10-17 20:38 ` Michael Niedermayer
2022-10-18 1:44 ` Peter Ross
2022-10-18 20:05 ` Michael Niedermayer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y00haAojX9+MMaDI@fec08ea42f77375e1b3adc0238ae6674 \
--to=pross@xvid.org \
--cc=ffmpeg-devel@ffmpeg.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
This inbox may be cloned and mirrored by anyone:
git clone --mirror https://master.gitmailbox.com/ffmpegdev/0 ffmpegdev/git/0.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 ffmpegdev ffmpegdev/ https://master.gitmailbox.com/ffmpegdev \
ffmpegdev@gitmailbox.com
public-inbox-index ffmpegdev
Example config snippet for mirrors.
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git