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

[Roman Ryltsov]

It is not quite clear how it scales if you don't request it. Perhaps you
could post some code, esp. your SWS context initialization arguments?

Roman

On Sat, Jan 5, 2013 at 5:55 PM, jim morgenstern <jmorgie at yahoo.com> wrote:

> 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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