Performance comparison nvenc vs qsv vs raspberry pi?

Question

fmpeg

Couldn't find benchmark results for transcoding video to h264 codec with ffmpeg.
Does anyone have experience comparing the speed and quality of video transcoding in h264 of the following technologies: *
CPU x86_64 libx264 (any cpu)
* Nvidia nvenc
* Intel Quick Sync Video
* raspberry pi OpenMAX
the same processing parameters.

Answer 1

In order to make such a spherical benchmark in a vacuum, you need to:
Take some file or stream , decide on the output format (video and audio codec, profile, fps, bitrate, encoding preset, frame spacing and GOP duration, the number of output bitrates and etc.)
Take a certain bare metal and run that benchmark.
The problem is that there is no correct answer to your question.
Again, in the presence of seemingly identical ffmpeg, hardware acceleration implementations differ from each other.
Conceptually:
1. CPU transcoding will give better quality and stability, but will be expensive due to low performance
2. NVENC / NVDEC gives moderate quality and stability (if you do not load it into a shelf) and high transcoding density, (and if you can patch firewood, the best cost per channel)
3. QSV gives moderate quality, so-so stability and fierce, frantic hemorrhoids in operation
4. Transcodenet 1 SD maximum.