Composite UVC (MJPEG) + UAC 2.0 Bandwidth Question

[RitchRock]

Hello,

I posted a question about adding audio to a UVC device at the end of a thread regarding AN00127.

Essentially, I want to see if I can extend the USB Ref design to also enumerate a basic UVC device, but I think it will require image compression. Here are my calculations:

Audio Rate:
8 ch * 48,000 samples/sec * 32 bits/sample = 12.3 Mbps

Uncompressed Video Rate:
1920 * 720 pixels * 16 bits/pixel * 30 fps = 663.6 Mbps

Total Uncompressed Rate:
12.3 Mbps (Audio) + 663.6 Mbps (Video) = ~676 Mbps


This uncompressed total is obviously too high for USB 2.0. This leads to my questions:

To stream this resolution, is MJPEG compression the correct approach?

If so, does XMOS provide an official library for JPEG encoding on the XU316?

My device needs 2 cameras for 360 FOV coverage, thats what gets me to the 1920 * 720 resolution. Thanks for the clarification.

[andrewxcav]

There is no supported JPEG library from XMOS. However, you can use the DCT functions from lib_xcore_math and, depending on your frame rate, you might be able to implement something that can "keep up."

How many frames per second are your targeting?