[FFmpeg-user] rgb8

[Kieran O Leary]

On Wed 31 May 2023 at 06:18, Michael Koch <astroelectronic at t-online.de>
wrote:

> Am 30.05.2023 um 22:53 schrieb Paul B Mahol:
> > On Tue, May 30, 2023 at 8:32 PM Michael Koch <
> astroelectronic at t-online.de>
> > wrote:
> >
> >> Am 30.05.2023 um 20:28 schrieb Reindl Harald:
> >>>
> >>> Am 30.05.23 um 20:21 schrieb Michael Koch:
> >>>> ffmpeg -f dshow -video_size 1280x800 -framerate 5 -pixel_format rgb8
> >>>> -i video="ASI178MM Camera (ZWO Design)" -f rawvideo -frames 1 -y
> >>>> test.raw
> >>>>
> >>>> Then I did read this file, assuming that the pixel format is gray:
> >>>>
> >>>> ffmpeg -s 1280x800 -pixel_format gray -f rawvideo -i test.raw -y
> >>>> gray.png
> >>>>
> >>>> The result looks correct. Is it possible to do this in one command
> >>>> line? I mean just tell FFmpeg that the pixel format isn't rgb8 but
> >>>> gray, without making any modifications to the data?
> >>> parameters before the input file are *input params*
> >>>
> >>> so why don't you change "-pixel_format rgb8" to "-pixel_format gray"
> >>> in the first command line when you say it works in the second one?
> >> When reading from the camera, the pixel format must be rgb8 because this
> >> is the only format supported by the DirectShow driver. All other pixel
> >> formats give error message.
> >>
> > Yes, looks like buggy code, the rgb8 is actually gray and not color.
>
> Is it possible to get correct gray data from the buggy driver in one
> FFmpeg command line? I mean the data can only be read from the driver as
> rgb8. Is it possible to tell FFmpeg that it's actually gray? It works as
> a two-step process with an intermediate raw file, but I'd like to do the
> same thing in one command line in realtime.



I’m not as familiar with this kind of usage but does adding “-pix_fmt gray
“ as an output option not work for you?

Kieran