[FFmpeg-user] Lavfi video generator slow performance

[Elliott Balsley]

Those are good questions, thank you.  I have 8 SSDs in RAID5 on a LSI 9361 SAS controller, formatted as NTFS.  I got the 3000 number from AJA System Test.  That test was writing a single file, so probably performance would drop when writing lots of small files.  I will benchmark again with small files.  I have no idea about ffmpeg’s write buffer size.

This machine has 28 real CPU cores, so I’m wondering if ffmpeg or lavfi is limited to one core?
Is there a way to verify whether disk write speed is the bottleneck by using ffplay?  When I run ffplay like this, I don’t see any fps readout, or maybe I don’t know where to look.

fifteen:~ elliott$ ffplay -f lavfi -i mandelbrot=s=3840x2160 -t 5
ffplay version 3.4.git Copyright (c) 2003-2018 the FFmpeg developers
  built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-librsvg --enable-libtheora --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --disable-libjack --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-indev=jack --enable-opencl --disable-outdev=xv --enable-audiotoolbox --enable-videotoolbox --enable-sdl2 --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-x86asm --enable-libx265 --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid --enable-nonfree --enable-libfdk-aac
  libavutil      56.  7.101 / 56.  7.101
  libavcodec     58. 11.101 / 58. 11.101
  libavformat    58.  9.100 / 58.  9.100
  libavdevice    58.  1.100 / 58.  1.100
  libavfilter     7. 12.100 /  7. 12.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  0.101 /  5.  0.101
  libswresample   3.  0.101 /  3.  0.101
  libpostproc    55.  0.100 / 55.  0.100
Input #0, lavfi, from 'mandelbrot=s=3840x2160':KB sq=    0B f=0/0   
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (RGB[0] / 0x424752), rgb0, 3840x2160 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc