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• FFMPEG - how to identify a bottleneck in hardware transcoding ?

  26 août 2021, par Henry

  In the provided example I was trying to transcode a 4K h264 source to a 1080p h264 output using Nvidia's Hardware acceleration.

  


  Relevant information :

  


  ffmpeg version git-2017-12-25-613f789 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 7.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-amf --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
  libavutil      56.  7.100 / 56.  7.100
  libavcodec     58.  9.100 / 58.  9.100
  libavformat    58.  3.100 / 58.  3.100
  libavdevice    58.  0.100 / 58.  0.100
  libavfilter     7.  7.100 /  7.  7.100
  libswscale      5.  0.101 /  5.  0.101
  libswresample   3.  0.101 /  3.  0.101
  libpostproc    55.  0.100 / 55.  0.100


  


  Command used :

  


  ffmpeg -c:v h264_cuvid -i "4K_input.mp4" -c:v h264_nvenc -preset slow -s 1920x1080 -c:a copy output.mkv


  


  Relevant PC Specs :

  


  GPU: (Gigabyte) GeForce GTX 1070 Ti
CPU: Intel Core i7 7700K
Memory: 8GB DDR4 2400MHz Single Channel.
SSD: Crucial CT525MX3


  


  While the Nvidia Desktop recording has absolutely no issues to record live h264 video in up to 50Mbps bitrates, this encoding at below 2600kbps was extremely slow utilizing barely 35% GPU.
I was unable to utilize 100% of the GPU on any video parameters.

  


  This is why I could use some advice concerning how to identify a (suspected) bottleneck.

  


• Set input frame rate in pygame.Camera

  14 mai 2018, par Thomas Hubregtsen

  I am trying to get an input stream from a webcam on OS X

  self.capture = pygame.camera('/dev/video{}'.format(camera),
  
                                   (640, 480), 'RGB')

  I get an error (see below), but there are 2 pieces of information that I can not really stitch together. On first sight, it looks like I do not have the correct camera (not video4linux). However, when running

  ffmpeg -f avfoundation -list_devices true -i ""

  I get it listed

  [AVFoundation input device @ 0x7fbb45700340] [1] FULL HD 1080P Webcam

  The next part of the error talks about frame rate. It appears that the frame-rate is slightly off, and that I just next to select a different frame rate. Would this be possible with pygcam ? Would this solve my problem ?

  Error :

  Traceback (most recent call last):
  
    File "webcam2.py", line 129, in <module>
  
      VideoStreaming("52.191.118.156", 5558, 1)()
  
    File "webcam2.py", line 22, in __call__
  
      with self.get_camera_context(self.camera_id) as frames:
  
    File "webcam2.py", line 89, in __enter__
  
  size=(640, 480))
  
    File "/Users/q433100/temp/brew-master/lib/python3.6/site-packages/imageio/core/functions.py", line 129, in get_reader
  
  return format.get_reader(request)
  
    File "/Users/q433100/temp/brew-master/lib/python3.6/site-packages/imageio/core/format.py", line 169, in get_reader
  
      return self.Reader(self, request)
  
    File "/Users/q433100/temp/brew-master/lib/python3.6/site-packages/imageio/core/format.py", line 218, in __init__
  
      self._open(**self.request.kwargs.copy())
  
    File "/Users/q433100/temp/brew-master/lib/python3.6/site-packages/imageio/plugins/ffmpeg.py", line 327, in _open
  
      self._load_infos()
  
    File "/Users/q433100/temp/brew-master/lib/python3.6/site-packages/imageio/plugins/ffmpeg.py", line 476, in _load_infos
  
      (self.request._video, ffmpeg_err))
  
  IndexError: No video4linux camera at <video1>.
  
  
  
  FFMPEG STDERR OUTPUT:
  
  
  
  ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  
    configuration: --prefix=/Users/q433100/temp/brew-master/Cellar/ffmpeg/3.4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  [avfoundation @ 0x7fbb9e000a00] Selected framerate (29.970030) is not supported by the device
  
  [avfoundation @ 0x7fbb9e000a00] Supported modes:
  
  [avfoundation @ 0x7fbb9e000a00]   160x120@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   176x144@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   320x240@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   352x288@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   640x360@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   640x480@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   800x600@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1024x576@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   960x720@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1280x720@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1392x768@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1280x960@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1600x896@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1920x1080@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   160x120@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   176x144@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   320x240@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   352x288@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   640x360@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   640x480@[30.000030 30.000030]fps
  
  [avfoundation @ 0x7fbb9e000a00]   800x600@[20.000000 20.000000]fps
  
  [avfoundation @ 0x7fbb9e000a00]   1024x576@[8.000000 8.000000]fps
  
  [avfoundation @ 0x7fbb9e000a00]   960x720@[15.000015 15.000015]fps
  
  1: Input/output error
  
  </video1></module>

  Update :
  If I try to force one of the mentioned supported frame rates with ffmped, I get a new error

  $ffmpeg -f avfoundation -r 30.000030 -i "1" out.mpg
  
  ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  
    configuration: --prefix=/Users/q433100/temp/brew-master/Cellar/ffmpeg/3.4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libavresample   3.  7.  0 /  3.  7.  0
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  [avfoundation @ 0x7fb3c8802600] An error occurred: The activeVideoMinFrameDuration passed is not supported by the device.  Use -activeFormat.videoSupportedFrameRateRanges to discover valid ranges.1: Input/output error

  Update 2 :
  Setting the input frame rate to 15 directly in ffmpeg works. Now I just need to figure out how to do this in python with pygame.camera

  $ ffmpeg -f avfoundation -r 15.000015 -i "1" out.avi

• Bash script : automate ffmpeg encoding for mpeg-dash

  13 février 2018, par Massimo Vantaggio

  I’m writing a bash file to create video encoding and concatenation for dash live streaming use,
  Basically it read an input video folder, encodes all videos into three resolution formats, after that it concatening them to create three adaption sets.

  DIAGRAM :

  

  This script checks for fps conformance,

  force/scaling resolution if the input is not 1920 x 1080p,

  Insert the channel logo png,

  Cut the end of all videos input in order to make them finish with closed gop, this to ensure that there are not videos with audio and video track with different lenght.

  ISSUE :

  Actually I’m not sure that the concatenation process respects the closed GOP alignment as it after the encoding..
  I try to cut also the end of the concatenation result in order to make it finish without decimals on a closed gop too, but im unable to erase all decimals from the total duration :

  total duration in seconds: 826.795000
  
  total duration corrected in seconds: 826

  But the real duration measured by ffprobe is

  824.044000

  I try to check keyframes alignment with mp4box has they teach without any result :

  MP4Box -info TRACK_ID source1.mp4 2>&1 | grep GOP

  This is the first time that i work with "video scripts" and probably i don’t know what input to give for TRACK_ID

  BASH SCRIPT :

  #!/bin/bash
  
  #CANCAT 0.2
  
  
  
  cd input
  
  times=()
  
  fps=()
  
  for f in *.mp4; do
  
  
  
      _t=$(ffprobe -i "$f" -show_entries format=duration -v quiet -of csv="p=0")
  
      times+=("$_t")
  
  
  
      _f=$(ffmpeg -i "$f" 2>&1 | sed -n "s/.*, \\(.*\\) fp.*/\\1/p")
  
      fps+=("$_f")
  
  done
  
  #SUM ALL DURATIONS
  
  TOTALDURATION=$( echo "${times[@]}" | sed 's/ /+/g' | bc )
  
  #DELETE DECIMAL
  
  DURROUND=$(echo "$TOTALDURATION" | cut -d'.' -f1) 
  
  #GET REST OF DIVISION BY 2 AS GOP
  
  TOTDELTA="$((DURROUND%2))"
  
  #SUBTRACT DELTA FROM TOTAL DURATION
  
  TOTDUR="$(($DURROUND-$TOTDELTA))"
  
  
  
  #GET NUMBER OF ELEMENTS IN FPS ARRAY  
  
  tLen=${#fps[@]}
  
  #CHECK FPS EQUALITY     
  
  for tLen in "${fps[@]:1}"; do
  
      if [[ $tLen != ${fps[0]} ]]; then
  
          printf "WARNING: VIDEO’S FRAME-RATE ARE NOT EQUALS, THE PROCESS CAN’T START."
  
          printf "%s\\0" "${fps[@]}" |
  
              sort -zu |
  
              xargs -0 printf " %s"
  
          printf "\\n"
  
         exit 1
  
      fi
  
  done
  
  for f in *.mp4; do
  
  #GET DURATION OF EACH VIDEO
  
  DUR="$(ffprobe -i "$f" -show_entries format=duration -v quiet -of csv="p=0")"
  
  DUR=$(echo "$DUR" | cut -d'.' -f1) # DELETE DECIMAL
  
  #GET FPS OF EACH VIDEO
  
  FPS="$(ffmpeg -i "$f" 2>&1 | sed -n "s/.*, \(.*\) fp.*/\1/p")"
  
  #ROUND FPS OF EACH VIDEO
  
  FPSC=$( echo "($FPS+0.5)/1" | bc )
  
  #REMOVE EXTENSION FROM VIDEO FILE NAME
  
  NAME=$(echo "$f" | cut -d'.' -f1)
  
  
  
  #GET GOP
  
  GOP="$((FPSC*2))"
  
  DELTADUR="$((DUR%2))"
  
  DUR="$(($DUR-$DELTADUR))"
  
  
  
  #ENCODE 1080p
  
  ffmpeg -y -i "$f" -i ../logo/logo.png -c:a aac -b:a 384k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -r $FPSC -b:v 4800k -maxrate 4800k -bufsize 3000k -profile:v main -crf 22 -t $DUR -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=1920:1080,setsar=1" ../buffer/${NAME}-1080.mp4
  
  
  
  #ENCODE 720p
  
  ffmpeg -y -i ../buffer/${NAME}-1080.mp4 -c:a aac -b:a 256k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -s 1280x720 -r $FPSC -b:v 2400k -maxrate 2400k -bufsize 1500k -profile:v main -crf 22 -t $DUR ../buffer/${NAME}-720.mp4
  
  
  
  #ENCODE 360p
  
  ffmpeg -y -i ../buffer/${NAME}-720.mp4 -c:a aac -b:a 128k -ar 48000 -ac 2 -async 1 -c:v libx264 -x264opts keyint=$GOP:min-keyint=$GOP:no-scenecut -bf 0 -s 640x360 -r $FPSC -b:v 800k -maxrate 800k -bufsize 500k -profile:v main -crf 22 -t $DUR ../buffer/${NAME}-360.mp4
  
  done
  
  
  
  
  
  #enter in buffer
  
  cd ..
  
  cd buffer
  
  
  
  #CONCAT 1080 SET
  
  # with a bash for loop
  
  for f in ./*1080.mp4; do echo "file '$f'" >> 1080list.txt; done
  
  
  
  ffmpeg -f concat -safe 0 -i 1080list.txt -t $TOTDUR -c copy ../output/1080set.mp4
  
  
  
  #CONCAT 720 SET
  
  # with a bash for loop
  
  for f in ./*720.mp4; do echo "file '$f'" >> 720list.txt; done
  
  
  
  ffmpeg -f concat -safe 0 -i 720list.txt -t $TOTDUR -c copy ../output/720set.mp4
  
  
  
  #CONCAT 360 SET
  
  # with a bash for loop
  
  for f in ./*360.mp4; do echo "file '$f'" >> 360list.txt; done
  
  
  
  ffmpeg -f concat -safe 0 -i 360list.txt -t $TOTDUR -c copy ../output/360set.mp4
  
  
  
  #CLEAN BUFFER
  
  rm *.mp4
  
  rm *.txt
  
  
  
  echo "CONCAT COMPLETED:"
  
  echo "frame-rate: $fps"
  
  echo "total duration in seconds: $TOTALDURATION"
  
  echo "total duration corrected in seconds: $TOTDUR"

  The full file with relative folders :

  BASH SCRIPT WITH FOLDERS

  RESULT VIDEO

  There is someone who can help me to understand why I can not eliminate the decimals of the total duration during concat ?
  And how to check overall keyframes allignment ?
  Also any impovement that i ignore is welcome !

  Thanks a lot !

  Massimo