ffmpeg usage

[memeka 0]

Hi,

 

I want to know if emby server will be able to transcode hw accelerated using my arm board's VPU.

I already have ffmpeg patched to make use of hardware acceleration, so I was wondering if I can have some example ffmpeg commands emby builds for transcoding, to check them beforehand (from command line) and debug them outside of emby.

 

Thank you!

 

[Luke 42078]

hi, using what encoder, VA API?

[memeka 0]

I am using a V4L2 encoder for Exynos MFC, it's not in upstream ffmpeg.

[Luke 42078]

How does it work? does it require proprietary commands or will it intercept commands that use libx264?

[memeka 0]

$ ffmpeg -codecs | grep h264
ffmpeg version 3.2.4-1 Copyright (c) 2000-2017 the FFmpeg developers
 DEV.LS h264                 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264_v4l2m2m h264 h264_vdpau ) (encoders: h264_v4l2m2m libx264 libx264rgb h264_omx h264_vaapi )

You can see here there's the libx264 encoder and the h264_v4l2m2m encoder that i want to use.

 

I can transcode a file with a command like: 

ffmpeg -i file.mkv -vcodec h264_v4l2m2m file-encoded.mp4

Actually h264_v4l2m2m currently it's set as "default" so it will be picked automatically just by something like "ffmpeg -i file.mp4 file-encoded.mp4". There should not be any proprietary stuff, it reads from ffmpeg settings like gop size, encoder bit rate, qmin/qmax and h264 profile. h264 level is currently hardcoded to 3.2, as the hardware even tho` it says it's supporting 4.0, it's not working well. I assume if other encoding options are set by ffmpeg, they will just be ignored.

 

This is why I would want to test a transcoding command generated by emby, and redirect output to a file, to be able to debug and modify the code for the encoder (e.g. maybe add more encoding options, if emby uses them).

 

EDIT: so i guess you can say it will intercept commands for libx264

Edited March 15, 2017 by memeka

[memeka 0]

Anyone can help with this?

[Luke 42078]

Hi, I'm happy to help, but example command lines are easy to find in server logs. All you have to do is play something. Here's one I just did right now:

ffmpeg.exe -analyzeduration 2000000 -f mpegts -i "http://127.0.0.1:8096/LiveTv/LiveStreamFiles/963c4588668a48be84f4ad0f6c976fb5/stream.ts" -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:1 -map -0:s -codec:v:0 libx264 -pix_fmt yuv420p -preset veryfast -crf 23 -maxrate 8000000 -bufsize 16000000 -vsync -1 -profile:v high -level 4.1 -level 41 -x264opts:0 subme=0:rc_lookahead=10:me_range=4:me=dia:no_chroma_me:8x8dct=0:partitions=none -force_key_frames "expr:gte(t,n_forced*3)" -vf "yadif=0:-1:0" -flags -global_header -max_delay 5000000 -avoid_negative_ts disabled -start_at_zero -codec:a:0 aac -strict experimental -ac 2 -ab 384000 -af "adelay=1,aresample=async=1,volume=2" -hls_time 3 -individual_header_trailer 0 -start_number 0 -hls_list_size 0 -hls_base_url "hls/8bba13bcbf97bdb546e9ed6ce1b146c8/" -y "C:\transcoding-temp\8bba13bcbf97bdb546e9ed6ce1b146c8.m3u8"

[Luke 42078]

@@memeka

 

The upcoming Emby Server 4.2 will have h264_omx built-in for Raspberry Pi hardware encoding. Thanks guys.