HLS on arm64

[chudsaviet]

HLS does not work on arm64 build.
This is the bug to track these issues.

[chudsaviet]

On 0.18.0 RC1 arm64 version, it was found that HLS stream is not working.

I have investigated these issues.

So far we were relying on RaspberryPi hardware h264 encoding capabilities.
Unfortunately, now there is no hardware encoding library /opt/vc/lib/libopenmaxil.so for arm64.
We can track next repositories on arm64 hardware encoding implementation:

1. https://github.com/raspberrypi/firmware
2. https://github.com/raspberrypi/userland

Basically, libopenmaxil.so is the part of userland repo. It's built and the binaries are put to the firmware repo. So far, it does not build for arm64.

Also, we will have to use FFmpeg built with --enable-omx-rpi flag, which is on by default for armhf and off for arm64.

[chudsaviet]

As a solution, we can use software h264 encoding. Actually, Raspberry Pi 4 is powerful enough to do this without interfering with OctoPrint wannabe-realtime core.

Good news is that even with veryfast preset, libx264 is producing much lower bitrate for given visual quality.

I think I will work on webcamd analog script written in Python3, which will be flexible enough to choose between software/hardware encoder.

[chudsaviet]

For now, users can manually set encoder to h264 instead of h264_omx, and set --preset:v veryfast in ffmpeg-hls Systemd unit.

[DrDrache]

not to add unuseful information,
but from my understanding OMX (openmax) will "never" come to 64bit userland. it would be a nightmare to map the VPU.
the current (supported?) h264 hardware-assisted method is h264_v4l2m2m via ffmpeg >=4.3

[chudsaviet]

Thanks, @DrDrache , it’s actually useful.
Yeah, I was trying to use V4L2M2M, but it had not supported all options I needed.
Let me try to investigate it more.

[chudsaviet]

Good news - h264_v4l2m2m works on Rpi4 on arm64, and pretty fast. :-D
I will work on a patch, and maybe we will switch armhf version to it too.

[chudsaviet]

Bad news: ‘h264_v4l2m2m’ encoder in ffmpeg is pretty buggy. It does not work correctly when I’m trying to split streams from webcam to two h264 and one jpeg stream.
I will investigate if we can use software encoder without overloading CPU.

[fastcompjason]

Any updates on this? I am trying to use an older Logitech Pro 9000 webcam with OctoPi running on a new RPi 4B+ 8GB and when I specifically enable HLS, I get nothing at all. I have even tried to specifically change the config file to specify a resolution and refresh rate. I would very much like to run a H.264 stream out of OctoPi to import into OBS or into other software hardware platforms for monitoring if possible.

[guysoft]

None, also found this and there seems to be no news there neither: jellyfin/jellyfin#4023 (comment)

[chudsaviet]

Yeah, we can only run the software encoder on arm64 for now.

[cryptoAlgorithm]

Bad news: ‘h264_v4l2m2m’ encoder in ffmpeg is pretty buggy. It does not work correctly when I’m trying to split streams from webcam to two h264 and one jpeg stream.

@chudsaviet yeah I observed that too, using h264_v4l2m2m in place of h264 throws a few errors, firstly the -preset option isn't supported, next the stream simply doesn't work with the preset removed. It works perfectly with h264 though, using around 110% CPU on my pi4b overclocked to 1.8GHz.