Unable to decode APP fields: Invalid data found when processing input

[Hommus]

I'm receiving continuous errors in the terminal. Images are actually coming through but something is obviously not working:

[swscaler @ 0x55a6346780] No accelerated colorspace conversion found from yuv422p to rgb24.
[mjpeg @ 0x55a619f3f0] unable to decode APP fields: Invalid data found when processing input
[swscaler @ 0x55a6345f70] No accelerated colorspace conversion found from yuv422p to rgb24.
[mjpeg @ 0x55a619f3f0] unable to decode APP fields: Invalid data found when processing input
...

<launch>
  <node name="usb_cam" pkg="usb_cam" type="usb_cam_node" output="screen" >
    <param name="video_device" value="/dev/video7" />
    <param name="framerate" value="30" />
    <param name="image_width" value="1920" />
    <param name="image_height" value="1080" />
    <param name="pixel_format" value="mjpeg" />
    <param name="color_format" value="yuv422p" />
    <param name="camera_frame_id" value="usb_cam" />
    <param name="io_method" value="mmap"/>
  </node>
</launch>

$ v4l2-ctl --list-formats-ext -d /dev/video6
ioctl: VIDIOC_ENUM_FMT
	Index       : 0
	Type        : Video Capture
	Pixel Format: 'H264' (compressed)
	Name        : H.264
		Size: Discrete 3840x2160
			Interval: Discrete 0.033s (30.000 fps)
			Interval: Discrete 0.067s (15.000 fps)
		Size: Discrete 1920x1080
			Interval: Discrete 0.033s (30.000 fps)

$ v4l2-ctl --list-formats-ext -d /dev/video7
ioctl: VIDIOC_ENUM_FMT
	Index       : 0
	Type        : Video Capture
	Pixel Format: 'YUYV'
	Name        : YUYV 4:2:2
		Size: Discrete 640x480
			Interval: Discrete 0.067s (15.000 fps)

	Index       : 1
	Type        : Video Capture
	Pixel Format: 'MJPG' (compressed)
	Name        : Motion-JPEG
		Size: Discrete 1920x1080
			Interval: Discrete 0.033s (30.000 fps)

[knorth55]

it seems your device does not support the decoding.
which CPU arch do you use?
do you use x86 or x86_64?

https://github.com/FFmpeg/FFmpeg/blob/master/libswscale/yuv2rgb.c#L682-L695

[Hommus]

@knorth55 I'm using a Jetson Xavier NX which I believe is aarch64.

[knorth55]

im not sure but it seems ffmpeg does not support swscale.
however, we can use hardware accelerated encoder/decoder for ffmpeg in jetson, probably.

[flynneva]

@Hommus doing a quick google this is completely normal behavior from ffmpeg it looks like.

I don't think anything is wrong. If you'd like to stop seeing these errors just adjust the av_set_log_level call to fatal and those errors should not be printed (I've done this already on the ros2 branch).

cc @knorth55

[Hommus]

Thanks @flynneva!