Hi Giovara,

SVT HEVC has the interface to enable/disable sending a vui structure in the 
HEVC bitstream, but supports no interface for setting the color properties 
before encoding yet. I will be opening an issue in SVT HEVC github asking if 
they have plans to add such feature, and will keep you posted. In the meantime, 
I think it is not blocking the first version of this plugin’s merging , is it?

VideoUsabilityInfo

Enables or disables sending a vui
structure in the HEVC Elementary
bitstream. 0 = OFF, 1 = ON


Regards,
SUN, Jing

From: Vittorio Giovara [mailto:vittorio.giov...@gmail.com]
Sent: Monday, March 11, 2019 10:50 PM
To: Sun, Jing A <jing.a....@intel.com>
Cc: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>; 
Huang, Zhengxu <zhengxu.hu...@intel.com>; Tmar, Hassene <hassene.t...@intel.com>
Subject: Re: [FFmpeg-devel] [PATCH v7 1/2] lavc/svt_hevc: add libsvt hevc 
encoder wrapper.



On Mon, Mar 11, 2019 at 12:50 AM Sun, Jing A 
<jing.a....@intel.com<mailto:jing.a....@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 found
Your message wasn't delivered to jun.z...@intel.com<mailto:jun.z...@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
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