[FFmpeg-devel] [PATCH] avcodec/dpxenc: support colour metadata in DPX encoder, fixes ticket #6023

[James Almer]

On 2/1/2017 9:42 AM, Kieran O Leary wrote:
> Hello,
> 
> I'm cc'ing Vittorio as I don't think that he's subscribed to the list but
> he's contributed to dpxenc.c and recent colorspace filters. The same with
> Kate Murray from the Library of Congress who knows a lot more about DPX
> than me. Apologies if this is inappropriate.
> 
> I mostly based this patch on other ffmpeg encoders, such as pncenc.c. I'm
> not really a C coder, I'm a moving image archivist who needs to be able to
> specify colour metadata in DPX for various workflows. Please excuse my
> ignorance/mistakes.
> 
> This patch adds documentation and two command line options for the DPX
> encoder:
> -trc (Transfer Characteristics) and -clr (Colorimetric Specification),

I may be missing something and apologizes if it was already mentioned, but
libavcodec already have options for these, color_trc and if i'm reading
this right colorspace, making use of the AVColorTransferCharacteristic and
AVColorSpace enums defined in avutil's pixfmt.h header.

Can't you use them instead?

> which set colour metadata values in a DPX file. Currently these are
> hardcoded to always be 2, aka Linear. Ticket #6023 is related to this, but
> there have also been many mailing list posts about this issue:
> https://ffmpeg.org/pipermail/ffmpeg-user/2015-March/025630.html
> https://ffmpeg.org/pipermail/ffmpeg-user/2015-December/029456.html