[FFmpeg-devel] [PATCH v7 1/2] lavc/svt_hevc: add libsvt hevc encoder wrapper.

[Vittorio Giovara]

On Mon, Mar 11, 2019 at 12:50 AM Sun, Jing A <jing.a.sun at intel.com> wrote:

> I just searched my inbox again but failed to find that email of question
> you mentioned.
>

Yeah I often see my mail bounced with this message:
Address not foundYour message wasn't delivered to *jun.zhao at intel.com*
because the address couldn't be found, or is unable to receive mail.

For reference this was the message on the mailing list
https://ffmpeg.org/pipermail/ffmpeg-devel/2019-March/240663.html

Could you please elaborate your request? What is the preservation for and
> how is it expected to work?
>

Yes of course, when you encode an HEVC stream you should be able to signal
how the color properties of the video buffers should be rendered. This is
usually conveyed with three parameters, the matrix coefficients, the color
primaries and the transfer characteristics. Without such information, the
data stored in the video may be interpreted differently and often
incorrectly by modern video players, causing image degradation, wrong
rendering and off colors.

For HEVC they are usually expressed in the stream itself, under the VUI,
and it is kinda expected that modern encoder allow to set them to any of
the applicable values.
In ffmpeg-land, they are represented by the colorspace, color_primaries and
color_transfer options in AVCodecContext and carried over through the whole
video processing.
-- 
Vittorio