i.MX ProcessorsのトピックRe: VPU Latency on i.MX6

VPU Latency on i.MX6

alexraimondi — Mon, 13 Jan 2014 19:31:51 GMT

I found this Q&A: How is VPU Latency on i.MX6: Q&A: How is VPU Latency on i.MX6

First, I can't access the referenced discussion: VPU Latency i.MX6. Is there a reason it is blocked?

The answer is not clear enough (at least for me ;-) ).

We need to implement an entire encoding/decoding system like this

Camera => encoder => transmission => decoder => display

What end to end (encoder input to decoder output) latency can we achieve?

We need less then 100ms. Is this possible?

Best regards

Alex

Re: VPU Latency on i.MX6

YixingKong — Tue, 14 Jan 2014 01:57:10 GMT

This discussion has been assgned to an engineer internally.

Re: VPU Latency on i.MX6

karina_valencia — Tue, 14 Jan 2014 16:21:40 GMT

Hi, Alex

   The latency discussed in #343081 is about the startup latency, is different with your case.
   For your case, I think 100ms is likely possible.
     - camera: assume camera capture one frame at 30ms interval
     - encoder: one frame delay, ~15ms(720p)
     - transmission: ~30 ms ?
     - decoder: one frame delay (suppose no reorder in video syntax), ~15ms(720p)
     - others: ~10ms

Eagle

Re: VPU Latency on i.MX6

alexraimondi — Tue, 14 Jan 2014 19:09:52 GMT

Hi Eagle

Thank you for your reply

So the encoding/decoding latency of approx. 15ms is a fact? That would be great news ;-)

I guess this is not related to the number of cores in the device, right?

Any suggestion on a hardware platform to use for a proof of concept?

Best regards

Alex

Re: VPU Latency on i.MX6

eaglezhou — Wed, 15 Jan 2014 06:57:38 GMT

Hi, Alex

The 15ms is average value estimated based one noreorder (only I/P frames exist) for 720p,

In most case, the decoding(or encoding) time for every frame should be less than 15ms.

Basically, the result is not related with core numbers.

ixM6DQ/DL/S are all suppose to be ok.

Eagle