ros2/common_interfaces

Add YUYV image encoding

Closed this issue · 3 comments

sgvandijk commented

Feature request

Feature description

Most popular USB cameras that are used in mobile/hobby robots, such as the Logitech C9xx cameras, provide images in YUV 4:2:2 format in YUYV order.

There is a YUV422 encoding defined in image_encodings.hpp but that is defined to be in UYVY order.

With an encoding constant defined for YUYV order we can then go on to handle that format in e.g. cv_bridge to convert it to other formats so there are no custom solutions needed like done in the ROS 1 usb_cam driver.

Implementation considerations

The implementation will be almost the same as for YUV422. The main consideration I think is the naming. Looking at https://www.fourcc.org/yuv.php the canonical name for this format seems to be YUY2, with YUYV being a synonym. OpenCV indicates the same in its conversion codes (e.g. COLOR_YUV2RGB_YUYV = COLOR_YUV2RGB_YUY2).

With that I'd propose either:

  1. YUY2
  2. YUV422_YUY2 <-- seems best to me
  3. YUV422_YUYV

I'd be happy to make a PR for this if this is accepted and a name is decided, and I then plan to add handling of it in cv_bridge as I'd like to use that in our V4L2 camera driver.

clalancette commented

I'd go for either 1 or 2. I have a slight preference for 1 (as it is less verbose), but I defer to your judgement on which is clearer. Please go ahead and open a PR for it; when you do, please be sure to include a link to exactly which pixel format you are talking about. Thanks!

mjcarroll commented

I'm good with either 1 or 2 with a preference towards 2. Looking forward to the PR!

clalancette commented

Fixed by #78, so closing.