Output ProRes encoding

[nicholas-fr]

When the source content is BT.2020 SDR or HDR, the script outputs HEVC, and in other cases (e.g. BT.709) the script outputs AVC.

This is because when trying ProRes output, there were concerns with the signalling of the transfer function, primaries and matrix coefficients, as they were not detected by VLC 3.0.10 when playing back the output encoding, even though the signalling was present according to ffmpeg.
VLC 3.0.10 correctly detected the same signalling in the original source ProRes content.
As this suggested an issue of some kind and time to investigate further was limited, it seemed safer to use AVC and HEVC.

Both ProRes encoders were tested:
-c:v prores_ks -profile hq
-c:v prores_aw

I may have overlooked something, or a newer version of ffmpeg (>4.2.2) may resolve the issue.

[rbouqueau]

GPAC has good support for ProRes. If you give me the full command-line + content + what to check, I can give it a try in my free time.

NB: since GPAC v0.9 (filters), GPAC can transcode by leveraging FFmpeg's libav* libraries.

[jpiesing]

@nicholas-fr ?

[jpiesing]

ffmpeg 5.0 has just been released with prores encoding and decoding listed as features.

[rbouqueau]

I think ProRes (the codec) has been supported for quite some time in FFmpeg. The addition here is about VideoToolbox. VideoToolbox is Apple's hardware acceleration API.

[jpiesing]

I think ProRes (the codec) has been supported for quite some time in FFmpeg. The addition here is about VideoToolbox. VideoToolbox is Apple's hardware acceleration API.

The current mezzanine content is HEVC because ffmpeg didn't output ProRes. ProRes would have been more logical.

[gitwjr]

Deferred for future work.