swscale support for Y416 as a pixel format

[rmk]

Currently Y416 is not supported as a pixel format. An example of where this is required is feeding the native Apple Prores 4444 codec with input data.

[Elon Musk]

Are there actual samples? I think mpc-hc supports Y416.

[compn]

it might be hard for us developers to produce Y416 prores files, could you create a sample for us?

also full ffmpeg output would be nice for you to report.
many problems are due to using old/outdated or bad forks of ffmpeg.

[Carl Eugen Hoyos]

From FFmpeg pov, yuv444p16 == Y416, no packed format will be added unless there is a usecase with a very good explanation.

[rmk]

The reason is that it is not possible to create media buffers with libavcodec that can be fed to the Apple encoder. Libavcocec being a general purpose library I thought it is also a use case to use libavcodec in a heterogenous (i.e. non-ffmpeg-only) set-up. Is there a specific reason for not supporting this if someone is willing to implement it?

[Carl Eugen Hoyos]

I would expect that a patch won't be rejected as long as it is clean and sufficiently optimised.

Can you explain the issues you have with FFmpeg's encoder?

[Carl Eugen Hoyos]

How does Apple call the required colour space in its documentation?

[Elon Musk]

kCVPixelFormatType_4444AYpCbCr16 = 'y416', /* Component Y'CbCrA 16-bit 4:4:4:4, ordered A Y' Cb Cr, full range alpha, video range Y'CbCr, 16-bit little-endian samples. */

[Carl Eugen Hoyos]

This was fixed in 3cb8eee6f7bff275081e640b7529f90c52fb3224