[FFmpeg-devel] dcp encoding + new pixel format request/sponsorship

Reimar Döffinger Reimar.Doeffinger at gmx.de
Tue Jan 22 09:12:15 CET 2013

On 21 Jan 2013, at 19:15, Michaël Cinquin <mc at michaelcinquin.com> wrote:
> Hi
> I just sent my first pull request from my first commits on GitHub : michaelcinquin.com:master.
> The pull request is about adding an rgb2xyz av_filter, which enables the processing of colors for digital cinema, from sRGB colorspace to XYZ, based on a 3x3 color matrix. This will hopefully make FFmpeg more useful for DCP encoding.
> There is one last show-stopper for making FFmpeg the main tool of opensource DCP encoding.
> FFmpeg does not support saving to RGB 3x12 bpp formats : this means we cannot output the 12-bit files necessary for Digital Cinema. Without a new pixel format, one has to save TIFFs out of ffmpeg, then encode them to j2K with another tool, which as far as I know cannot be piped.
> Could I get help or sponsor the development of a new pixel format that will enable libopenjpeg to save 12 bips per channel J2K ?

Is there any reason to add a 12 bit per component format instead of using the 16 bit one and telling the encoder it should discard 4 bit?
I believe the reason that the 9 and 10 bit formats exist is that they are used for reference frames and using the 16 bit format for the reference frames would slow things down a good bit.

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