Crash without tracebacks when extract frames from some webm in vp9 yuv420p and convert to rgba

[laggykiller]

Overview

Extracting frames from some webm in vp9 yuv420p and convert to rgba cause crash of entire python without any tracebacks and message.

Expected behavior

Convert the frames into rgba, or at the very least, throw exception instead of crashing the whole python

Actual behavior

Entire python crash without any tracebacks and message.

Traceback:
None, the whole python crashes without any traceback

Investigation

Setting format='rgb24' instead of format='rgba' does not trigger the crash.

Note that other files that are also vp9 yuv420p do not trigger the crash.

Reproduction

004.webm
021.webm

import av
with av.open('004.webm') as container:
    for frame in container.decode(video=0):
        frame.reformat(format='rgba')

webm samples that are also vp9 yuv420p but do NOT trigger the crash:
002.webm
003.webm

Versions

• OS: Windows 11
• PyAV runtime:

PyAV v9.2.0
library configuration: --disable-static --enable-shared --libdir=/c/cibw/vendor/lib --prefix=/c/cibw/vendor --disable-alsa --disable-doc --disable-mediafoundation --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --disable-libxcb --enable-libxml2 --enable-libxvid --enable-lzma --enable-version3 --enable-zlib
library license: GPL version 3 or later
libavcodec     58.134.100
libavdevice    58. 13.100
libavfilter     7.110.100
libavformat    58. 76.100
libavutil      56. 70.100
libswresample   3.  9.100
libswscale      5.  9.100

Research

I have done the following:

• Checked the PyAV documentation
• Searched on Google
• Searched on Stack Overflow
• Looked through old GitHub issues
• Asked on PyAV Gitter
• ... and waited 72 hours for a response.

PS: https://gitter.im/PyAV-Org is down (404 not found)

[jlaine]

It looks like your report is against an old version of PyAV. Can you please try reproducing this with PyAV 10.0 or better yet with main?

[laggykiller]

@jlaine Reproducible even with 10.0.0

[WyattBlue]

I could not reproduce this in 11.0.0. When running @laggykiller 's code, the program logged this:

No accelerated colorspace conversion found from yuv420p to rgba.
No accelerated colorspace conversion found from yuv420p to rgba.
 (repeated 48 more times)

then exited successfully.

[laggykiller]

Looking back, seems like this is reflecting the same problem in #1269