Hi Marek!!!
Why do they call MEDIASUBTYPE_RGB32 something that is BRG ? !
Why do WE call XBGR something that is BGRX? !!
Besides our insanity, your patch looks sane. Thanks for it :)
There are some patches on the queue to remove the format definitions,
so your patch might not apply cleanly, I guess Laurent will take care
of it
Thanks
On Mon, 16 Jan 2023 at 11:50, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>
> Hi Marek,
>
> Thank you for the patch.
>
> On Mon, Jan 16, 2023 at 10:40:32AM +0100, Marek Vasut wrote:
> > The Cypress EZUSB FX3 UVC example can be configured to report pixel
> > format "e436eb7e-524f-11ce-9f53-0020af0ba770". This is its GUID for
> > BGRA/X 8:8:8:8.
> >
> > The UVC 1.5 spec [1] only defines GUIDs for YUY2, NV12, M420 and I420.
> > This seems to be an extension documented in the Microsoft Windows Media
> > Format SDK[2]. This Media Format SDK defines this GUID as corresponding
> > to `MEDIASUBTYPE_RGB32`, which is confirmed by [4] as `MEDIASUBTYPE_ARGB32`
> > has different GUID.
> >
> > Note that in my case, the FX3 UVC can output either channel order,
> > BGR or RGB or any other mix for that matter. Since Linux commit
> > 1b8dc32286a1a ("[media] uvcvideo: Add GUID for BGR 8:8:8")
> > defined a GUID for `MEDIASUBTYPE_RGB24` channel order as BGR, keep
> > this change consistent and define `MEDIASUBTYPE_RGB32` as BGR as well.
> > Document [3] also indicates the channel order is BGR.
> >
> > [1] https://www.usb.org/document-library/video-class-v15-document-set
> > [2] https://learn.microsoft.com/en-us/windows/win32/wmformat/media-type-identifiers
> > [3] https://learn.microsoft.com/en-us/windows/win32/directshow/uncompressed-rgb-video-subtypes
> > [4] https://gix.github.io/media-types/
> >
> > Signed-off-by: Marek Vasut <marex@xxxxxxx>
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Reviewed-by: Ricardo Ribalda <ricardo@xxxxxxxxxxx>
>
> > ---
> > Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> > Cc: William Manley <will@xxxxxxxxxxxxxxxxx>
> > ---
> > V2: - Reference document [3] confirming BGR channel order
> > - Reference document [4] describing MEDIASUBTYPE_ARGB32 with different GUID
> > - Use V4L2_PIX_FMT_XBGR32 instead of V4L2_PIX_FMT_BGR32 which is deprecated
> > ---
> > include/media/v4l2-uvc.h | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/include/media/v4l2-uvc.h b/include/media/v4l2-uvc.h
> > index f83e31661333b..b010a36fc1d95 100644
> > --- a/include/media/v4l2-uvc.h
> > +++ b/include/media/v4l2-uvc.h
> > @@ -99,6 +99,9 @@
> > #define UVC_GUID_FORMAT_BGR3 \
> > { 0x7d, 0xeb, 0x36, 0xe4, 0x4f, 0x52, 0xce, 0x11, \
> > 0x9f, 0x53, 0x00, 0x20, 0xaf, 0x0b, 0xa7, 0x70}
> > +#define UVC_GUID_FORMAT_BGR4 \
> > + { 0x7e, 0xeb, 0x36, 0xe4, 0x4f, 0x52, 0xce, 0x11, \
> > + 0x9f, 0x53, 0x00, 0x20, 0xaf, 0x0b, 0xa7, 0x70}
> > #define UVC_GUID_FORMAT_M420 \
> > { 'M', '4', '2', '0', 0x00, 0x00, 0x10, 0x00, \
> > 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
> > @@ -266,6 +269,11 @@ static struct uvc_format_desc uvc_fmts[] = {
> > .guid = UVC_GUID_FORMAT_BGR3,
> > .fcc = V4L2_PIX_FMT_BGR24,
> > },
> > + {
> > + .name = "BGRA/X 8:8:8:8 (BGR4)",
> > + .guid = UVC_GUID_FORMAT_BGR4,
> > + .fcc = V4L2_PIX_FMT_XBGR32,
> > + },
> > {
> > .name = "H.264",
> > .guid = UVC_GUID_FORMAT_H264,
>
> --
> Regards,
>
> Laurent Pinchart
--
Ricardo Ribalda
