Can't set video stream handler_name on qtrle : compat broblem with broadcast hardware

[NNois]

ffmpeg N-90414-gabf35afb6f

Hi, some broadcast hardware require the handler_name to be "Apple Alias Data Handler"

setting handler_name or just handler doesn't make it

example of metadata

-c:v qtrle -pix_fmt bgra -g 1 -filter_complex "setfield=tff" -flags +ildct -acodec pcm_s16le -metadata major_brand="qt" -metadata compatible_brands="qt" -metadata:s:v:0 encoder="Animation" -metadata:s:v:0 handler_name="Apple Alias Data Handler" -metadata:s:v:0 handler_name="Apple Alias Data Handler"

[Carl Eugen Hoyos]

Which hardware needs this?
How did you verify that the handler_name is the only issue?

[Carl Eugen Hoyos]

I believe this was fixed by Gyan Doshi in 830695be366ff753a3f7b8dd97c10d3e6187d41c

[Gyan]

There's a hitch when writing MOVs. Two hdlr atoms are written. Once, within mdia and then within minf. The specified handler name is correctly written in the mdia child atom, as can be confirmed with any atom parser, like movdump. But when writing hdlr within minf, the track object isn't passed on* and hence the metadata isn't used. So the generic value of DataHandler gets written.

When ffmpeg demuxes a MOV, the minf is processed after mdia and so the handler name metadata key is reset with the generic value.

*this has been the case since the original code was added in 2003. I thought of changing it, but close to 100 FATE references would need to be updated. That's tedious but I'm ready to carry that out (will take some time) if other devs don't object.

[Carl Eugen Hoyos]

Replying to Gyan:

I thought of changing it, but close to 100 FATE references would need to be updated. That's tedious but I'm ready to carry that out (will take some time) if other devs don't object.

Why is it tedious?

[Gyan]

I'll have to confirm that all affected refs have changed hash just due to changes in that string and nothing else.

[Carl Eugen Hoyos]

Replying to Gyan:

I'll have to confirm that all affected refs have changed hash just due to changes in that string and nothing else.

No, it is sufficient to send a patch for review.

[Gyan]

Ok, will send one this weekend. Thanks.

[Gyan]

Patch at ​https://patchwork.ffmpeg.org/patch/9648/

[Gyan]

Fixed in 8aa6d9a8d37b365c8989d11e0d1b0e8aee493ece