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>
---
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,
--
2.39.0
