FPS decrease strangely in GStreamer

toanjunifer — Mon, 11 May 2020 07:48:43 GMT

Hi,

I'm trying to record dual camera with HD and VGA resolution.

I got an issue and to show that I made a comparison:

Case 1: I set a video to HD / 15 FPS and other one to VGA / 15 FPS--> all FPS is only 7.5.

I check with memory bandwidth, I get:

CPU: 93%

i.MX6DL detected.
MMDC VPU
MMDC new Profiling results:
***********************
Measure time: 500ms
Total cycles count: 198030942
Busy cycles count: 119997582
Read accesses count: 528408
Write accesses count: 282512
Read bytes count: 15751008
Write bytes count: 5832608
Avg. Read burst size: 29
Avg. Write burst size: 20
Read: 30.04 MB/s / Write: 11.12 MB/s Total: 41.17 MB/s
Utilization: 2%
Overall Bus Load: 60%
Bytes Access: 26

Case 2: I record one video with FullHD resolution / 30 FPS --> FPS is 30.

And memory bandwidth result:

CPU: 3%

i.MX6DL detected.
MMDC VPU
MMDC new Profiling results:
***********************
Measure time: 501ms
Total cycles count: 198093642
Busy cycles count: 128261872
Read accesses count: 5880020
Write accesses count: 3275750
Read bytes count: 172924032
Write bytes count: 67611776
Avg. Read burst size: 29
Avg. Write burst size: 20
Read: 329.17 MB/s / Write: 128.70 MB/s Total: 457.87 MB/s
Utilization: 23%
Overall Bus Load: 64%
Bytes Access: 26

I bold some parameter which are difference. I have some question.

1. Why case 1 FPS is so low while CPU usage is almost maximum ? And Utilization is also quite low ?

2. What are difference of 2 cases in usage of VPU side and memory bandwidth side ?

3. How to increase FPS in case 1 ?

I'm a newbie. So forgive me if I asked some stupid question.

Thank you,

Toan

Re: FPS decrease strangely in GStreamer

joanxie — Thu, 21 May 2020 08:24:28 GMT

i.mx6 vpu encoder only supports one stream of 1080p with better performance, if you need to encode dual video, you can try 720P

Re: FPS decrease strangely in GStreamer

toanjunifer — Thu, 21 May 2020 09:34:08 GMT

Hi joanxie‌,

Thank you so much for your reply.

topic Re: FPS decrease strangely in GStreamer in i.MX Processors

FPS decrease strangely in GStreamer

Re: FPS decrease strangely in GStreamer

Re: FPS decrease strangely in GStreamer