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>
> ---
> 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
