[Libav-user] change pixel format without scaling data ? // more 1

jim morgenstern jmorgie at yahoo.com
Sat Jan 5 16:55:24 CET 2013

I have 10 bit data;  I am converting from say YUV422 to YUV444 or RGB etc.;
swscale is useful for changing the pixel format.  But I find that my 10bit
data is getting scaled to 16 bit such that when I output only 10bits I have,
well, wrap around etc.  I am not asking ffmpeg to rescale the data
automatically, I want the scale left alone.

So a) is there a better way to change pixel format?  B) a way to turn off
gray-level scaling ??

-----Original Message-----
From: libav-user-bounces at ffmpeg.org [mailto:libav-user-bounces at ffmpeg.org]
On Behalf Of Carl Eugen Hoyos
Sent: Saturday, January 05, 2013 10:27 AM
To: libav-user at ffmpeg.org
Subject: Re: [Libav-user] change pixel format without scaling data ?

jim morgenstern <jmorgie at ...> writes:

> I am using sws_scale to change the pixel formatting but this routine 
> is also changing the scale of the data graylevel values themselves and 
> I do not want it to.

I am not sure I understand:
Are you converting from GRAY8 to GRAY8A without changing the resolution but
the values are changed?

Generally, swscale should be used both if you want to change a frame's
resolution and if you only want to change the pix_fmt.

Carl Eugen

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