Question about fx3 isochronous mode in UVC

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
JiKi_2103446
Level 1
Level 1
First like received

Hi,

We want stream video data from image sensor with UVC on isochronous mode in Super Speed(USB 3.0).

We are referring to the AN75779 example code, but this exmaple is using Bulk mode.

Our camera environment  is 1280x720 / 30 fps / YUV format(uncompressed).

So we need about 55MB/s(1280x720x2x30x8) bandwidth.

As I know,

due to UVC driver constraints, FX3's maximum bandwidth on ISOC endpoint under UVC for USB 3.0 in Windows 7/8 is 24MB/s.

Only with Windows 10, maximum bandwidth will be 24MB/s X 16 = 384MB/s.

(See AN75779 document 4 page Note..)

Q1 >
In the above environment, Should the host use only Windows 10 for sufficient bandwidth support?
If the host use windows 7/8, is our camera unusuable on isochronous mode?
Although it is available, is it operating up to 24MB/s?

Q2 >
For isochronous mode setting, Can I change only the endpoint configuration on descriptor file in example code? 
Do I need addtional work? (eg. data packet, thread callback configuration..)

Thank you in advance.

1 Solution
Anonymous
Not applicable

Hi,

Windows 7 does not support Burst mode for ISoC UVC. The maximum burst length is 1 for UVC IsoC in Win 7. So it is better to opt bullk mode.

Regards,

- Madhu Sudhan

View solution in original post

0 Likes
3 Replies
Anonymous
Not applicable

Hi,

For ISoC UVC, you can refer to the USBVideoClass example in FX3 SDK EXamples list.

However we recommend you to use Bulk for UVC for more efficiency.

Regards,

- Madhu Sudhan

0 Likes

Thank you for reply.

Could you explain the detailed explanation about more efficiency?

Our system requires ISoC mode for guaranteed bandwidth.

Is it possible to use more than 55MB/s bandwidth in ISoC mode?

If not specific or technical reason, We would like to use ISoC.

0 Likes
Anonymous
Not applicable

Hi,

Windows 7 does not support Burst mode for ISoC UVC. The maximum burst length is 1 for UVC IsoC in Win 7. So it is better to opt bullk mode.

Regards,

- Madhu Sudhan

0 Likes