Other NXP ProductsのトピックRe: Issue on using vpudec to decode video in h.264 format (i.MX8MP)

Issue on using vpudec to decode video in h.264 format (i.MX8MP)

Cheok98 — Mon, 13 Oct 2025 09:51:47 GMT

I have encountered issue of high latency and CPU usage when using vpudec (Gstreamer plugin) to decode h.264 video stream from an IP camera using i.MX8MP board.

the gstreamer script I used to run the application is as follows:

$ gst-launch-1.0 rtspsrc location=<rtsp_source> latency=0 ! rtph264depay ! h264parse ! vpudec ! fakesink

I have used the GST_DEBUG tool to print out the interlatency and cpuusage between each event and the figures below are the results I obtained.

When using vpudec:

When using v4l2h264dec:

When using avdec_h264:

As you can see from the pictures, when using vpudec, the cpu usage is still very high (20 - 48%), and the latency is about 600ms. When using v4l2h264dec, the cpu usage is between (11 - 41%), the latency is about 500ms. While using avdec_h264, the cpu usage is between (14 - 32%), and the latency is about 80ms.

Based on my testing, the avdec_h264 has the lowest latency to decode the video, while vpudec has the highest cpuusage and latency which is abnormal.

May I know, is there anything that I need to configure in the meta-layer before building the Yocto image for the vpu to work? For this application, I have built my own custom image using imx-image-core as the base. Thanks in advance!

Re: Issue on using vpudec to decode video in h.264 format (i.MX8MP)

Cheok98 — Mon, 13 Oct 2025 09:55:14 GMT

By the way, the Yocto version I used to build my image is kirkstone 5.15.71_2.2.0 release

Re: Issue on using vpudec to decode video in h.264 format (i.MX8MP)

Bio_TICFSL — Mon, 13 Oct 2025 14:44:16 GMT

Hello,

You should try the latest BSP since there is a problem with gstreamer in version 5.xx

Regards

Re: Issue on using vpudec to decode video in h.264 format (i.MX8MP)

Cheok98 — Wed, 15 Oct 2025 03:53:56 GMT

Hi,

I have tried running the same application with image built by Yocto scarthgap (kernel 5.0). But the vpudec still take very long time (600ms) to decode the h264 video.