[FFmpeg-user] Color Shift when encoding DNxHD QuickTime video on Windows

[Carl Lindqvist]

>I am a software developer working for an animation studio. I have been
>tasked with creating DNxHD QuickTime videos which are then imported into
>Avid Media Composer (An Editing Suite Application using DNxHD and MXF as
>it's preferred codec and format). Our studio uses Windows 7. I have noticed
>a color shift when comparing the media encoded by FFmpeg to the media
>created by Avid when importing the frames directly (Note: Avid will encode
>a DNxHD MXF from the image files on import). We create the QuickTime videos
>ourselves because it reduces the import time given that Avid will only
>change the video container without having to do any real encoding. I hope
>this makes sense, I am not an expert in this area. I have compared the
>output when using other software packages such as RVIO and Nuke. RVIO
>doesn't match the video created by Avid but it also doesn't match the video
>created by FFmpeg whereas Nuke is able to match the video created by Avid.
>I am interested to learn about what causes the color shift. Attached is the
>output from the FFmpeg command I am using and the output from an ffprobe
>query on both an input image and the output video. Note: The input images
>are in sRGB color space. Any feedback will be much appreciated.

It is probably a color matrix issue. In most cases you will want to
use Rec601 for SD and Rec709 for HD when converting RGB to YUV, but it
depends on the destination. If the wrong conversion is used, the
colors will be slightly off (purple-ish or orange-ish skin tones,
difference in saturation). Look at this post for a good example
picture:

http://forum.videohelp.com/threads/329866-incorrect-collor-display-in-video-playback?p=2045830&viewfull=1#post2045830

/Carl