Why Gstreamer encoding takes more cpu load while encoding .yuv than .mp4

Hariharan1 — Tue, 28 Oct 2025 06:07:19 GMT

In the case of the i.MX VPU Hantro, while encoding a 1080p video, I considered two different approaches:

MP4 → YUV → H.264
MP4 → H.264

I noticed that the first approach consumes significantly more CPU load compared to the second approach. Is that intermediate conversion required?

1) Approach 1

>decode mp4 to yuv

gst-launch-1.0 filesrc location=5MB_1080p.mp4 ! qtdemux ! h264parse ! imxvpudec_h264 ! filesink location=1080p.yuv

CPU load: 90 %

>encode yuv to h264

gst-launch-1.0 filesrc location=1080p.yuv ! videoparse width=1920 height=1080 format=nv12 framerate=30/1 ! imxvpuenc_h264 ! h264parse ! filesink location=1080p.h264

CPU load: 35.9%

2) Approach 2

> Decode and Encode in a Single Pipeline

gst-launch-1.0 filesrc location=5MB_1080p.mp4 ! qtdemux name=demux demux.video_0 ! h264parse ! imxvpudec_h264 ! imxvpuenc_h264 ! h264parse ! filesink location=enc.h264

CPU load: 6.6%

Re: Why Gstreamer encoding takes more cpu load while encoding .yuv than .mp4

pengyong_zhang — Tue, 28 Oct 2025 09:13:07 GMT

Hi @Hariharan1

yes, you are right, At approach 1, The primary causes of high CPU load are: extensive data writes to disk and data shuffling during the decoding process. But approach 2, There are no intermediate disk write and read operations; data is directly transferred in memory. So, in your current scenario, approach 2 is the best choice.

B.R

i.MX ProcessorsのトピックWhy Gstreamer encoding takes more cpu load while encoding .yuv than .mp4

Why Gstreamer encoding takes more cpu load while encoding .yuv than .mp4

Re: Why Gstreamer encoding takes more cpu load while encoding .yuv than .mp4