From: Anton Khirnov <anton@khirnov.net>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH v2 08/12] lavc/frame_thread_encoder: avoid assigning a whole AVCodecContext
Date: Sun, 24 Mar 2024 12:23:32 +0100
Message-ID: <171127941251.1646.3410638245731734758@lain.khirnov.net> (raw)
In-Reply-To: <GV1P250MB073742DE8ED2F5BE050D81E08F372@GV1P250MB0737.EURP250.PROD.OUTLOOK.COM>
Quoting Andreas Rheinhardt (2024-03-24 12:10:24)
> Anton Khirnov:
> > Quoting Andreas Rheinhardt (2024-03-24 11:19:19)
> >> Anton Khirnov:
> >>> Quoting Andreas Rheinhardt (2024-03-23 15:11:59)
> >>>> 1. The earlier code would just work in case the user used a smaller
> >>>> number of elements for the matrices if these matrices were not used at
> >>>> all (which happens for the majority of encoders). This is no longer true
> >>>> with this patch.
> >>>
> >>> So?
> >>>
> >>
> >> It means there is a scenario where you break something.
> >
> > There is no way for the caller to know whether, and how much, will lavc
> > read from those tables, so it's invalid API use.
> >
>
> Incorrect: Given that these fields do not a length field, it is legal to
> put pointers to matrices of arbitrary length in the relevant
> AVCodecContext field.
No. Users are not allowed to write random values to random places.
The only meaningful way to use these arrays is with 64 elements,
therefore any caller using a different number is broken.
--
Anton Khirnov
_______________________________________________
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:[~2024-03-24 11:23 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-22 20:28 [FFmpeg-devel] [PATCH 01/12] tests/fate/ffmpeg: evaluate thread count in fate-run.sh rather than make Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 02/12] fftools/ffmpeg_demux: only call filter_codec_opts() when we have a decoder Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 03/12] fftools/cmdutils: do not use a random codec's private options Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 04/12] fftools/ffmpeg_dec: apply decoder options manually Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 05/12] fftools/ffmpeg_{demux, dec}: pass -bitexact through DecoderFlags Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 06/12] fftools/ffmpeg_dec: apply cropping manually Anton Khirnov
2024-03-23 2:53 ` James Almer
2024-03-23 7:20 ` Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 07/12] fftools/ffmpeg_filter: remove display matrix if we have applied it Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 08/12] lavc/frame_thread_encoder: avoid assigning a whole AVCodecContext Anton Khirnov
2024-03-22 20:42 ` Andreas Rheinhardt
2024-03-23 14:00 ` [FFmpeg-devel] [PATCH v2 " Anton Khirnov
2024-03-23 14:11 ` Andreas Rheinhardt
2024-03-24 9:27 ` Anton Khirnov
2024-03-24 10:19 ` Andreas Rheinhardt
2024-03-24 10:33 ` Anton Khirnov
2024-03-24 11:10 ` Andreas Rheinhardt
2024-03-24 11:23 ` Anton Khirnov [this message]
2024-03-24 0:11 ` [FFmpeg-devel] [PATCH " Michael Niedermayer
2024-03-24 9:29 ` [FFmpeg-devel] [PATCH v3 " Anton Khirnov
2024-03-24 11:25 ` Andreas Rheinhardt
2024-03-24 11:36 ` Anton Khirnov
2024-03-27 10:27 ` [FFmpeg-devel] [PATCH v4 " Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 09/12] lavc/decode: move sd_global_map to avcodec Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 10/12] lavc/encode: map AVCodecContext.decoded_side_data to coded_side_data Anton Khirnov
2024-03-23 2:33 ` James Almer
2024-03-23 7:20 ` Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 11/12] fftools/ffmpeg_enc: stop copying demuxer side data to the muxer Anton Khirnov
2024-03-22 20:28 ` [FFmpeg-devel] [PATCH 12/12] fftools/ffmpeg_demux: make InputStream.autorotate private Anton Khirnov
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=171127941251.1646.3410638245731734758@lain.khirnov.net \
--to=anton@khirnov.net \
--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