Performance Issue H264Platinum Codec ( High Profile, Res-640x480 frame rate-10,15)

Hi Sujith,

Please change the Bitrate control to VBR. You will not see this problem.

regards

Yashwant

Hi Yashwant,

thanks for your reply.

in my camera we need to support both VBR and CBR.

once the target bit rate i am reducing by 100 kb slowly the lower person of the video the scatered portion increases.

i was refering to the document SPRABA9, where you have suggested rcQMax 44 and for very low bitrate you have suggested to increase.

i need to check this particular point.

also for CBR - RateControlPrest is selected IVIDEO_LOW_DELAY and for VBR IVIDEO_STORAGE in our setting.

if Constant BitRate what other things to be taken care ?

why this problem is happening with one resolution only ?

CBR makes sure that the max picture size does not increase in a way to cause buffer overflow. Hence the I frame, which generally takes more bits than P frame does not get enough bits and has some blockiness at the bottom of the frame. If your application does not require CBR, I suggest you to move to VBR. VBR also meets the target bitrate and the quality will be good.

In case you want I frame to be still of good quality(in CBR), you can modulate rcQMaxI to lower value say 36 or below. Please let rcQMax to be still 44. 

But it is interesting to not that you are seeing the issue only for VGA. I will ckech this and revert back to you.

regards

Yashwant

Hi Yashwant,

we are observing thi problem only in VGA resolution and bitrate lesthan equal to 2048Kbps.

other resolutions it is absolutely fine with CBR and VBR also.

i enabled PerteptualIRC =1 and also increased MaxDelay from 1000 to 2000.

now i am getting better picture at the bottom.

so you are going to check the same issue in VGA please consider the PerteptualIRC  and Maxdelay also.

so that we will get exact details with VGA.

the document written by you and team is really helpfull to get an idea about all the parameters.

it will be helpfull for us if you will verify today and inform.

Hi Sujith,

Can you share the config for other resolution (other than vga) because the problem should not be resolution dependent.

Hi Adithya,

i was now verifying with H264 1.10 version.

with the same conditions there is absolutely no issues.

picture is ok at the bottom also.

so where is the bottleneck. is there any issues with Platinum Codec only using Constant Bitrate ?

Hi Sujith,

RC underwent changes from ver 1.1 to ver 2.0. In ver 1.1, there was problem of excessive frame skips and HRD non compliace  in CBR mode which was solved by modulating the I frame bits in ver 2.0.

In case your application still needs good quality I frame, you will have to increase maxDelay and/or decrease rcQMaxI.

regards

Yashwant