[Libav-user] Colour space conversion

wm4 nfxjfg at googlemail.com
Fri May 29 09:15:35 CEST 2015

On Fri, 29 May 2015 05:10:41 +0000
Jasleen Kaur <Jasleen at beesys.com> wrote:

> ________________________________________
> From: libav-user-bounces at ffmpeg.org [libav-user-bounces at ffmpeg.org] on behalf of wm4 [nfxjfg at googlemail.com]
> Sent: Wednesday, May 27, 2015 6:30 PM
> To: libav-user at ffmpeg.org
> Subject: Re: [Libav-user] Colour space conversion
> On Wed, 27 May 2015 09:42:11 -0300
> Rafael Lúcio <rafael at inova.in> wrote:
> > If you convert any RGB format to YUV420 you will lose data. If you want to
> > just change the format to YCbCr without losing data.. you can try YUV444
> > format... its 3 bytes per pixel, just like RGB, so you will not lose any
> > data.
> >
> That's quite misleading. yuv420 will of course lose data, but it's also
> the standard for video compression (which typically _also_ loses data
> additional to the yuv conversion). And converting between yuv444 and
> RGB is also a lossy operation (at least if both use the same bit depth).
> What I mean by colours change is for example ...that orange becomes blue, blue becomes green, gray remains gray.
> Really confused over the solution , Do I used yuv444 instead to solve this ?

No. If this happens, there is a major bug. Maybe switched U/V planes.

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