The upcoming Firefox version 127 from [1] fails to play videos using the H.264
codec using libavcodec61 (matching FFmpeg 7) and logs

[Child 17872, MediaDecoderStateMachine #1] WARNING: Decoder=7f4534045f00 Decode
error: NS_ERROR_DOM_MEDIA_FATAL_ERR (0x806e0005) - mozilla::MediaResult
mozilla::FFmpegDataDecoder<61>::InitDecoder(AVDictionary**): Couldn't open
avcodec: file
/home/abuild/rpmbuild/BUILD/firefox-127.0/dom/media/MediaDecoderStateMachineBase.cpp:167

to stderr.

Removing libavcodec61 so that only libavcodec60 remains appears to resolve the
problem for now.

[1] https://build.opensuse.org/package/show/mozilla/firefox127