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• GOP size does not correlate with actual latency

  28 mai 2019, par Alex

  As far as I know, GOP size should correlate with observable video delay (latency). For example, if GOP size is 2, then delay in video should be near two seconds and so on, at least with CBR. But, when I set GOP size to 2, publish stream to ingest server, consume this stream and measure latency, it is between 0.8-1.2 seconds, not 2+ seconds as excepted. Increasing GOP size leads to same results : with GOP 4 latency is near 2.5 seconds, not 4 seconds.

  How I measure this latency : stream working stopwatch from web-camera using OBS to ingest server and calculate difference between stopwatch value and value displayed in stream consumed from ingest. For greater measurement accuracy, I make a photo with stopwatch and actual image from ingest in one field of view.

  My OBS settings is here :

  

  Can you suggest, why do I get such results and how relevant is my statement about correlation between GOP size and video latency ? Maybe, H264 settings like "zerolatency" makes some magic ?

  Thanks.

• video not playing - moov atom not found

  28 mai 2019, par LivvyJefferson

  Video wont play - ffmpeg "moov atom not found"

  I have downloaded ffmpeg to troubleshoot the problem of why videos seemed to be corrupted - wont play on any media player, converting in VLC does not work.

  Last login: Tue May 28 10:41:47 on ttys000
  
  Livvys-MacBook-Air:~ livvy$ ffmpeg -i /Users/livvy/Desktop/help.MOV -c copy output.mov
  
  ffmpeg version 4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
  
    built with Apple LLVM version 9.0.0 (clang-900.0.39.2)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.3_1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ff893008200] Format mov,mp4,m4a,3gp,3g2,mj2 detected only with low score of 1, misdetection possible!
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7ff893008200] moov atom not found
  
  /Users/livvy/Desktop/help.MOV: Invalid data found when processing input
  
  Livvys-MacBook-Air:~ livvy$ 

  I have tried to install ubuntu, - to try and generate a new moov atom for the file by using a working video taken on the same device - it tells me I need to install a JVD, tried that and can’t export the file.
  Basically, I do not code and trying to do this off of various google searches.
  Is there an easier way to install a moov atom to this video without accidently effing up my computer with faulty code ? Or should I just give up and lose the videos ?

  Any help appreciated - sorry for lack of knowledge/hopelessness

• FFMPEG | How to attach a path URL for .ts chunks in m3u8 ?

  29 mai 2019, par mendy25

  What I need to do is to add a full path address inside the m3u8 for each .ts

  How to do it please ?

  Example :

  #EXTM3U
  
  #EXT-X-VERSION:3
  
  #EXT-X-TARGETDURATION:10
  
  #EXT-X-MEDIA-SEQUENCE:0
  
  #EXTINF:10.000000,
  
  http://...com/tsfiles/2019-05-29_12:40:41.ts
  
  #EXTINF:10.000000,
  
  http://...com/tsfiles/2019-05-29_12:40:45.ts
  
  #EXTINF:10.000000,
  
  http://...com/tsfiles/2019-05-29_12:40:51.ts

  The result / command right now :

  ffmpeg -y -user_agent 'VLC/2.1.4 LibVLC/2.1.4' -i *** -strftime 1 -strftime_mkdir 1 -force_key_frames expr:'gte(t,n_forced*10)' -hls_time 10 -hls_segment_filename /var/www/html/tsfiles/%Y-%m-%d_%H:%M:%S.ts /var/www/html/m3u8files/stream.m3u8
  
  
  
  
  
  #EXTM3U
  
  #EXT-X-VERSION:3
  
  #EXT-X-TARGETDURATION:10
  
  #EXT-X-MEDIA-SEQUENCE:0
  
  #EXTINF:10.000000,
  
  /var/www/html/tsfiles/2019-05-29_12:40:41.ts
  
  #EXTINF:10.000000,
  
  /var/www/html/tsfiles/2019-05-29_12:40:45.ts
  
  #EXTINF:10.000000,
  
  /var/www/html/tsfiles/2019-05-29_12:40:51.ts