[FFmpeg-devel] [PATCH] libavformat\matroskadec.c: crop support for matroska demuxer.

Dmitrii Ovchinnikov ovchinnikov.dmitrii at gmail.com
Mon Sep 26 17:22:17 EEST 2022


Hi Andreas,

Thanks for your quick and direct feedback about the patch. Your feedback
about the displayWidth, displayHeight and the display aspect ratio shows
that you have deep thinking in this area.

I have several questions and comments about your feedback.

1. Yes, i will get this change, and put the added fields at the rear part
of AVCodecParameters
2. I will split these changes into different commits. Should I also split
the edits in the AVCodecContext and codec_pack.c files into different
commits?
3. Yes, I will apply the container cropping info additionally to the
bitstream cropping.
4. Yes, I will apply the cropping for receive_frame API as well.
5. I'm also working on “clean aperture” for MP4 container. mov is a part of
the subset of MP4. I will submit that patch to ffmpeg after i finished it.
Maybe one month later.
6. Thanks for a good reference.
7. Yes, there are many problems in the MKVToolNix. MKVToolNix may result in
some inconsistent of display aspect ratio when editing crop information.
There are two part of work(for support of Matroska cropping), one part is
matroska encoder, another is matroska decoder. This time i submit the
matroska decoder patch. In the matroska encoder, i have already taken the
inconsistent into consideration, and did some work to make sure it keeps
consistent. Do you want me to put the matroska encoder and matroska decode
together in the same patch to submit ffmpeg, or do you want I put them in
two separate patch and submit seperately?


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