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• ffmpeg hwo to choose the best bit rate for HLS streaming ?

  7 février 2023, par Josef Kranz

  I'm building a video streaming white label product, but I've run into the following scenario where I'm not sure what might be the optimal way to get the best video quality in return. At the moment I'm using crf based encoding, which is from a streaming based point of view a very bad idea. From a quality point of view, it will definitely give me the best quality and also the best efficiency. Why is crf based encoding bad for streaming ? First you have a non-fixed file size, meaning your bit rate might vary between 20 kbps and 20 Mbit/s depending on the codec and picture motion of the current frames ...
When you have such heavily varying stream according to the bit rate, automatic quality selection at the player might not function correctly, and the player automatically switches from 1080p to 480p for no reason (using VideoJS here).

  


  To fix this issue, it's fine if I set minrate, maxrate with ffmpeg but this will also come at the cost that some frames might look pixelated, which I absolutely do not want.

  


  Currently, my encoding command looks something like this :

  


  /usr/bin/ffmpeg -i "/tmp/VODProcessing/Tester 2160p UHD-HDR.mp4" -map 0:0 -c:v libsvtav1 -crf 19 -vf zscale=width=3840:height=2160 -svtav1-params "profile=0:enable-force-key-frames=1:superres-mode=1:enable-tf=0:tune=0:enable-overlays=1:scd=1:scm=2:enable-mfmv=1:enable-cdef=1:enable-dlf=1:fast-decode=1:color-primaries=9:transfer-characteristics=16:matrix-coefficients=9:input-depth=10:mastering-display=G(0.265,0.69)B(0.15,0.06)R(0.68,0.32)WP(0.3127,0.329)L(4000.0,0.005):content-light=368,226:enable-hdr=1:color-range=1" -pix_fmt yuv420p10le -color_trc smpte2084 -color_primaries bt2020 -colorspace bt2020nc -chroma_sample_location:v topleft -color_range:v pc -max_muxing_queue_size 1024 -preset 7 -bf 0 -force_key_frames "expr:gte(t,n_forced*4.004)" -keyint_min 48 -sc_threshold 0 -use_timeline 1 -use_template 1 -map_metadata -1 -map_chapters -1 -f hls -seg_duration 4.004 -hls_time 4.004 -streaming 1 -hls_list_size 0 -hls_segment_filename "/tmp/VODProcessing/output/Tester 2160p UHD-HDR/v-av01-2160p-av01.0.12M.10_PQ/f-%04d.m4s"  -hls_fmp4_init_filename "init-v-av01-2160p-av01.0.12M.10_PQ.m4s"  -hls_segment_type fmp4 -hls_playlist_type vod -movflags frag_keyframe+frag_every_frame+write_colr+prefer_icc+skip_trailer+faststart -hls_flags independent_segments -strict experimental "/tmp/VODProcessing/output/Tester 2160p UHD-HDR/v-av01-2160p-av01.0.12M.10_PQ/master.m3u8"


  


  Which will form a stream made out of independent m4s segments. As you can see, I'm using libsvtav1 in crf mode to output the result in AV1.

  


  Now my question is, how can I have the same nice quality output as with the crf mode while having a static/fixed bit rate ? Will 2 pass encoding solve this problem by distributing the pixels or data rate differently ?

  


  Thanks in advance

  


• Using ffmpeg to check if playlist file is empty or not

  14 septembre 2022, par qwertynik

  Before using an m3u8 file to create a mp4 video, is there any FFmpeg command using which it can be checked if the playlist is empty or not ?

  


  Command used to create a video using a playlist file without any segments (.ts files)

  


  ffmpeg -i 57cfa531e34771a4e945c6926c108428_1ed332b9-c0e7-6146-a164-064ee1bc8164.m3u8 -vcodec copy -acodec copy -absf aac_adtstoasc recording.mp4


  


  Output :

  


  ffmpeg version 3.4.8 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-39)
  configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic' --extra-ldflags='-Wl,-z,relro ' --extra-cflags=' ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libcdio --enable-libdrm --enable-indev=jack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopus --disable-encoder=libopus --enable-libpulse --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzvbi --enable-avfilter --enable-avresample --enable-libmodplug --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-libmfx --enable-runtime-cpudetect
  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
Empty playlist
57cfa531e34771a4e945c6926c108428_1ed332b9-c0e7-6146-a164-064ee1bc8164.m3u8: End of file


  


  The above command prints the fact that the playlist is empty. Can this information alone be retrieved from FFmped without attempting to create a video ?

  


  m3u8 files for experimentation :

  


  


  • Empty playlist

    


  


  • Non-empty playlist

    


  


  


• Applying fades between images ffmpeg command

  29 octobre 2015, par Jon Stevens

  I am trying to create a video slideshow that fade out/in between each image solely from an ffmpeg cli command. After researching this for hours, the only way I discovered that this was possible was to use the -filter_complex argument and pass in all images and specify a complex filter that defines multiple fades out and back in that I could time to happen between frames. The command I have so far :

  ffmpeg -y -framerate 1/5 \
  
  -loop 1 -i img-1.jpg \
  
  -loop 1 -i img-2.jpg \
  
  -loop 1 -i img-3.jpg \
  
  -filter_complex \
  
  "[1:v]fade=out:4:d=1,fade=in:5:d=1[fad1]; \
  
  [2:v]fade=out:9:d=1,fade=in:10:d=1[fad2]; \
  
  [3:v]fade=out:14:d=1,fade=in:15:d=1[fad3];" \
  
  -c:v libx264 -r 25 -pix_fmt yuv420p test.mp4

  Here’s the output from executing this command :

   ffmpeg version 2.6.4 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 5.1.1 (GCC) 20150618 (Red Hat 5.1.1-4)
  
    configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic' --enable-bzlib --disable-crystalhd --enable-frei0r --enable-gnutls --enable-ladspa --enable-libass --enable-libcdio --enable-libdc1394 --disable-indev=jack --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-openal --enable-libopencv --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-x11grab --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  
    libavutil      54. 20.100 / 54. 20.100
  
    libavcodec     56. 26.100 / 56. 26.100
  
    libavformat    56. 25.101 / 56. 25.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 11.102 /  5. 11.102
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, image2, from img-1.jpg':
  
    Duration: 00:00:05.00, start: 0.000000, bitrate: 141 kb/s
  
      Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 72:72 DAR 16:9], 0.20 fps, 0.20 tbr, 0.20 tbn, 0.20 tbc
  
  Input #1, image2, from img-2.jpg':
  
    Duration: 00:00:00.04, start: 0.000000, bitrate: 17789 kb/s
  
      Stream #1:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 67:67 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  Input #2, image2, from 'img-3.jpg':
  
    Duration: 00:00:00.04, start: 0.000000, bitrate: 17764 kb/s
  
      Stream #2:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 62:62 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  [AVFilterGraph @ 0xbc2a00] No such filter: ''
  
  Error configuring filters.

  All I am trying to do is create a video slideshow with fades/transitions between images. Any help is greatly appreciated !