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• How to get the information of bit-rate from YouTube videos ?

  21 février 2017, par Ashutosh Singla

  I was using YouTube videos for my test and I was wondering how can I get the information of bit-rate of the played video ?

  I used 2 methods to know the information about the bit-rate but didn’t get any information.

  1. Right-click on a video and choose "Stats for nerds".
  
  2. ffmpeg -i input_video -f ffmetadata metadata.txt

  I don’t know if by doing the right click on the video and then properties, then details would give me the correct way of showing the bit-rate.

  Any suggestions ?

• FMP4 moof box sequence number ordering

  15 avril 2024, par Daniel

  I wanted to do a basic fragmented mp4 broadcast program with avformat libs and HTML5 video and MSE.

  



  This is a live stream and I use avformat to copy h264 data to mp4 fragments.

  



  Here is my basic drawing of clients attaching to the stream :

  



  

  



  So, with words :

  



  

  1. C1J : First Client joins :


     

     • avformat process starts

     


     • ftyp, moov, moof, mdat boxes will be served to Client1

     


     • ftyp and moov atoms are both saved for later reuse

     


  


  2. C2J : Second Client joins (later in time) :


     

     • avformat process is ongoing (because it is still serving moof and mdat boxes for Client1)

     


     • previously saved ftyp and moov boxes will be served first to Client2

     


     • after ftyp and moov boxes were served, Client2 will join to the stream at the next moof box.

     


  


  



  I have saved an mp4 file to disk from both clients.

  



  Atoms' order within both files looks good : ftype, moov, moof, mdat, moof, mdat...

  



  Both files can be played by media players (like VLC) and also in browsers directly (Opera).

  



  Client1 can be played also via MSE in the browser (Opera), but Client2's stream is not displaying with MSE (Opera).

  



  No errors on the JS console, and media-internals looks also good (at least equivalent with Client1's one).

  



  Now I realized that every moof box contains an mfhd box (header) with a sequenceNumber field.

  



  Of course in Client1's first moof box this sequenceNumber is 1.
However in the later joined Client2's first moof box this sequenceNumber is always >= 1 (in my case it is 16).

  



  What do I need to modify in the moof boxes in Client2 to have a valid fmp4 from the beginning ?

  



  I think Opera's HTML5 video does not like if sequenceNumber does not start from 1, but there shall be other requirements for being it valid.

  


• Correct settings for streaming audio and video to YouTube

  27 novembre 2020, par Claus

  I'm using this script to stream an .mp4 video file with a sound track in .mp3 format :

  


  ffmpeg \
-re \
-i "$VIDEO_SOURCE" \
-thread_queue_size 512 \
-i "$AUDIO_SOURCE" \
-c:v libx264  -pix_fmt yuv420p -preset $QUAL -r $FPS -g $(($FPS *2)) -b:v $VBR \
-c:a $AUDIO_ENCODER -threads 6 -ar 44100 -b:a 128k -bufsize 512k -pix_fmt yuv420p \
-f flv $YOUTUBE_URL/$YOUTUBE_KEY


  


  the video gets displayed correctly on the channel but I cannot get any audio played.

  


  No error message on the console. What am I missing ?