i.MX ProcessorsのトピックZero latency VPU h264 encoder with periodic intra frame support?

Zero latency VPU h264 encoder with periodic intra frame support?

moire59 — Fri, 27 Mar 2015 14:45:18 GMT

The documentation is vague about it and there are no previous questions I could find.

Is this encoder profile supported from the imx6 platform?

Thank you.

Re: Zero latency VPU h264 encoder with periodic intra frame support?

gavingreenwalt — Fri, 27 Mar 2015 16:13:12 GMT

If you find a solution please let me know.

Re: Re: Zero latency VPU h264 encoder with periodic intra frame support?

moire59 — Fri, 27 Mar 2015 17:00:24 GMT

Well, from this question: https://community.freescale.com/thread/311299

and this quote from the manual:

intraRefresh where 0 = Intra MB refresh is not used. Otherwise = At least N MB's in every P-frame are encoded as intra MB's.

It should be possible to have intra refresh P frames, while having maybe 1 I frame every few hours? Depending on how that number is declared? Even if it's a 16 bit one it should still be quite a lot of frames before an I one.

But maybe my understanding of it is completely wrong.

Re: Zero latency VPU h264 encoder with periodic intra frame support?

jamesbone — Tue, 07 Apr 2015 21:29:01 GMT

Giovanni,

You are correct the intraRefresh parameter is the latency and you can control the I-frames and P-frames in the EncOpenParam structure, modifing the Gobsize

typedef struct {

CodStd bitstreamFormat;

PhysicalAddress bitstreamBuffer;

Uint32 bitstreamBufferSize;

Uint8 *virt_bitstreamBuffer;

int streamBufResetEnable;

int picWidth;

int picHeight;

Uint32 frameRateInfo;

int bitRate;

int initialDelay;

int vbvBufferSize;

int enableAutoSkip;

int gopSize;

int sliceMode;

int sliceSizeMode;

int sliceSize;

int intraRefresh;

int sliceReport;

int mbReport;

int mbQpReport;

union {

EncMp4Param mp4Param;

EncH263Param h263Param;

EncAvcParam avcParam;

} EncStdParam;

} EncOpenParam;

Gobsize

0 – Only first picture is I, 1 – all I pictures, 2 – IPIP…, 3 – IPPIPP…

The maximum value is limited by 60.

Re: Zero latency VPU h264 encoder with periodic intra frame support?

moire59 — Wed, 08 Apr 2015 00:21:06 GMT

Hi, and thank you for the answer.

Can you also confirm that the encoder doesn't support slice based encoding (or rather it does, but it can't output/input slices instead of full frames, so I need to wait for the full frame during the encoding and during the decoding, and I add 2 frames of latency to my application without considering anything else?

Thank you.