H.264 VBR Encoding in i.MX6

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H.264 VBR Encoding in i.MX6

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ko-hey
Senior Contributor II

Hi all

I have a question about i.MX6 VPU API in L4.1.15.
Specifically, I want to test H.264 VBR encoding which has bitrate limitation in i.MX6.

I set following parameters but it shows no change.

・userQpMin
・userQpMax
・bitRate
・userQpMinEnable


Also following thread said i.MX6 doesn't support useQPMin paratemer, too.
https://community.nxp.com/thread/391632


Is the above thread correct ?


furthermore, if someone know the other method to achieve H.264 VBR encoding with bitrate limitation, please tell me how to do.


Ko-hey

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5 Replies

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ko-hey
Senior Contributor II

 Could someone follow this thread and reply the question ?

Ko-hey

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681 Views
joanxie
NXP TechSupport
NXP TechSupport

As I known, if you want to test VBR, bitrate should set to 0, and you should set quant number, refer to the vpu api document, quantParam is used for all quantization parameters with VBR (no rate control). The range of value is 1-31 for MPEG-4 and 0-51 for H.264. When rate control is enabled, this field is ignored.

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681 Views
ko-hey
Senior Contributor II

Hi

Thank you for reply.

I tried set to a quantParam and understood that it can use for test VBR in static.

However, automatically (dynamically) changing a QP is my purpose of using userQpMin and userQpMax.

So it doesn't suit for me.

Do you have any idea that doing dynamically bitrate limitation in i.MX6 ?

Ko-hey

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681 Views
joanxie
NXP TechSupport
NXP TechSupport

what do you mean that doing dynamically bitrate limitation? you want to set bitrate on the fly or no bitrate control?

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681 Views
ko-hey
Senior Contributor II

Sorry for Insufficient description.

When user set quantParam, the bitrate becomes a specific value.

This means that anytime same bitrate.

However, when user use userQpMin and userQpMax parameter, the bitrate becomes various value.

I said that is dynamically.

Could you understand my meaning ?

Ko-hey

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