[FFmpeg-user] convert from bt601 to bt709
bobm-ffmpeg at burner.com
Fri Jun 6 10:35:01 CEST 2014
On 6/6/2014 12:46 AM, Carl Eugen Hoyos wrote:
> Imo, that's mostly because so far, nobody has uploaded
> a RGB image which is not full-scale.
Where would you like one? I can provide an unlimited number of them
(they are pretty easily made.) I can collect together all kinds of
samples when I get to the office tomorrow.
I found some references to -color_range but browsing quickly through the
source it seems only hooked up to a few specific codecs.
On 6/6/2014 12:28 AM, tim nicholson wrote:
> ISTR that if you give ffmpeg RGB it assumes its full range
That's what I've found; Giving it 10-bit RGB DPX files already at 709
levels (64-940 and 709 color matrix) and going to DNxHD it was scaling
the levels again, as if the input was full range.
> it also by default converts using 601 matrices.
That's probably true as well; 601 and 709 are kinda close, and my test
images weren't particularly saturated so the shift I was seeing was not
I could make things worse though using -vf colormatrix=bt601:bt709 :)
Ignoring the overall range scaling, not using colormatrix in this
instance gets pretty close -- maybe only as close as is possible for
RGB->YUV->RGB (since I was inevitably looking at the results as RGB) but
I'll have to revisit in the morning because I don't completely remember
-- my number of test compression files last night was getting out of
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