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Hi, I’ve 2 questions for cyfxuvcdscr.c - CyFxUSBSSConfigDscr[ ]’s “class specific uncompressed VS frame” descriptor in AN75779 example.
Q1: Min/Max bit rate bits/s field is NOT MATCH actual situation
According to the definition in UVC spec:
However, I still don’t understand clearly. Does it means that the max/min range for the total bits per second?
Min/Max bit rate bits/s value: 0x31975000 = 832,000,000bps
1 frame bytes: 1280 * 720 * 2 = 1,843,200
Total bits in 30 frames: 1,843,200 * 8 * 30 = 442,368,000bps
832,000,000bps > 442,368,000bps: So the situation(720p, 2bytes for 1 pixel, 30fps) is still valid?
Q2: Maximum video or still frame size field is NOT MATCH actual situation
According to AN75779:
I found the field is correspond totally in High Speed’s descriptor(480p):
High speed descriptor: 0x00096000 = 614,400
Actual frame size: 640 * 480 * 2 = 614,400
However, in Super Speed descriptor(720p), the value isn’t match…
Super speed descriptor: 0x001FA400 = 2,073,600
Actual frame size: 1280 * 720 * 2 = 1,843,200
2,073,600 > 1,843,200: So the situation is still valid?
Any help will be highly appreciated!
Solved! Go to Solution.
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USB Superspeed Peripherals
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Hello,
You can set the descriptor fields same as what you have calculated. That is:
Max and Min bit rates = 1280*720*16*30 = 0x1A5E0000
Max frame size = 1280*720*2 = 0x1C2000
It should work fine with the above settings.
Jayakrishna
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Hello,
You can set the descriptor fields same as what you have calculated. That is:
Max and Min bit rates = 1280*720*16*30 = 0x1A5E0000
Max frame size = 1280*720*2 = 0x1C2000
It should work fine with the above settings.
Jayakrishna