[FFmpeg-user] ffmpeg x264 encoding performance

[Henk D. Schoneveld]

On 09 Jan 2014, at 13:49, Mitja Pirih <mitja at alternet.si> wrote:

> Hi,
> 
> My questions are:
> 1. Is there a reference data to compare my ffmpeg performance to?
> 2. Should I expect a better performace from this system?
> 3. Any hints how to improve my config?
> 
> Hardware specs:
> IBM x3650 server, 24GB RAM, dual quad core CPU X5365  @ 3.00GHz
> 
> #lsb_release -a
> No LSB modules are available.
> Distributor ID:    Ubuntu
> Description:    Ubuntu 13.10
> Release:    13.10
> Codename:    saucy
> 
> #uname -a
> Linux IPTV 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:20:46 UTC 2013
> x86_64 x86_64 x86_64 GNU/Linux
> 
> # ffmpeg
> ffmpeg version git-2014-01-03-6275d93 Copyright (c) 2000-2014 the FFmpeg
> developers
>  built on Jan  3 2014 14:42:16 with gcc 4.8 (Ubuntu/Linaro 4.8.1-10ubuntu9)
>  configuration: --prefix=/root/ffmpeg_build
> --extra-cflags=-I/root/ffmpeg_build/include
> --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin
> --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac
> --enable-libmp3lame --enable-libopus --enable-libtheora
> --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree
>  libavutil      52. 59.100 / 52. 59.100
>  libavcodec     55. 47.100 / 55. 47.100
>  libavformat    55. 22.102 / 55. 22.102
>  libavdevice    55.  5.102 / 55.  5.102
>  libavfilter     4.  0.103 /  4.  0.103
>  libswscale      2.  5.101 /  2.  5.101
>  libswresample   0. 17.104 /  0. 17.104
>  libpostproc    52.  3.100 / 52.  3.100
> Hyper fast Audio and Video encoder
> 
> 
> Currently this system is using a USB TBS-5280 dual tuner and mumudvb to
> grab all DVB-T video&audio streams in the air and broadcast everything
> into multicast (total 10 SD + 2 HD streams in h264). I use ffmpeg to
> transcode that stream. My ffserver.conf:
> <Stream stream001.mkv>
> Feed stream001.ffm
> NoLoop
> Format matroska
> VideoCodec libx264
> VideoFrameRate 25
> VideoBitRate 1524
> VideoSize 720x576
> AVOptionVideo preset ultrafast
> AVOptionVideo tune zerolatency
> AVOptionVideo flags +global_header
> AVOptionVideo crf 26
This is rather ‘lowish’ quality, default is 23 where lower numbers is higher quality, but also slower encoding.
Further the crf flag disables VideoBitRate
> AVOptionVideo me_range 16
> AVOptionVideo qdiff 4
> AVOptionVideo qmin 10
> AVOptionVideo qmax 51
> AudioCodec aac
> Strict -2
> AudioBitRate 128
> AudioChannels 2
> AudioSampleRate 44100
> AVOptionAudio flags +global_header
> </Stream>
> 
> I am able to push 6 streams with this config everything above that I
> experience CPU exhaustion.
> 
> The transcoded stream should be compatible with android IPTV devices
> running XBMC on a 42" TV, so I am open to suggestions for improvements.
> 
> Thanks,
> Mitja
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