topic Re: Maximum Delay from camera input to display output in i.MX Processors

Maximum Delay from camera input to display output

ko-hey — Fri, 14 Nov 2014 05:01:57 GMT

Hi all I'm designing a system with i.MX6Solo. And I'm concerned about the delay from camera input to display output. My system has two lines. One line is camera through that is including from YUV to YCbCr format conversion. The other is encoding camera input (720P@30Hz) in H.264 and save to SD card. The system will operate at the same time. Then, I have a question about a above system. Is the maximum system delay can be achieved within 2 frame? Addition to above, is there any possibility to achieve within 1 frame? Please give your opinion. Just for information, I found a following contribution. But no one answered. https://community.freescale.com/message/451281#451281 Best Regards,

Re: Maximum Delay from camera input to display output

igorpadykov — Sat, 15 Nov 2014 00:44:35 GMT

Hi ko-hey

I am afraid delay can not be achieved within 2 frames, in general

VPU latency encoding is about 3 frames but may be bigger depending

on used algorithm. For example one can check below links

http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

http://mewiki.project357.com/wiki/X264_Encoding_Suggestions#Encoder_latency

Best regards

igor

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Re: Maximum Delay from camera input to display output

ko-hey — Tue, 18 Nov 2014 01:05:39 GMT

Hi Igor

Thank you for your reply.

I understood H.264 needs about 3 frames.

As described above, I have two lines in my system.

One doesn't need H.264 compression.

In that line, do you think it also can't achieve 2 frames?

Best Regards,

Re: Maximum Delay from camera input to display output

igorpadykov — Tue, 18 Nov 2014 01:20:50 GMT

Hi ko-hey

without VPU I think it

can achieve 2 frames.

~igor

Re: Maximum Delay from camera input to display output

ko-hey — Tue, 18 Nov 2014 01:33:24 GMT

Hi Igor

Thanks.

How about within 1 frame? Can it achieve?

If you have any experience, please let me know.

ko-hey