SVQ1 fourcc is wrong for AVI container

[Carl Eric Codere]

Summary of the bug: When using the svq1 codec and using AVI as output container, the fourcc output may be invalid, as it is in lower case while in Qt it is in upper case, so it cannot be recognized by ffdshow. VLC does accept both svq1 and SVQ1 as AVI fourcc.

How to reproduce:

% ffmpeg -y -benchmark -i foreman_cif.avi -codec:v svq1 foreman_cif_svq1_ffmpeg.avi 2>foreman_cif_svq1_ffmpeg.avi.txt
ffmpeg version : ffmpeg-4.4-2460-2c6f532-win32-static-xpmod-sse.7z
built on 2021-01-02 

Workaround:

% ffmpeg -y -benchmark -i foreman_cif.avi -codec:v svq1 -vtag SVQ1 foreman_cif_svq1_ffmpeg2.avi

See attached mediainfo exports.

[Carl Eugen Hoyos]

Why do you believe that upper-case would be more correct than lower-case for a format that the creator has not defined for avi?

[Carl Eugen Hoyos]

For future tickets: MediaInfo output is rarely useful (and not useful in this case), ffmpeg console output is required for every valid ticket.

[Carl Eric Codere]

Your comment is valid, but i do feel that it is curious that in mov files the FOURCC in uppercase in this case, as defined by the codec manufacturer, and it was decided to make it lower case in AVI files.

If you feel this is not an issue, and it was decision by the FFMPEG team at the time, and it could break backward compatibility today, i understand and the ticket can be closed, at least if people ever see the issue on their side they can search in the issue tracker here and find the explanations.

p.s: Apologies on using mediainfo instead of ffprobe.

[Carl Eugen Hoyos]

At the time was in d91712990c965462b7744078dec2fb6c4d29ce89
I wonder if a change on our hand would help at all: If ffdshow changes their code, even old files would be played, no?