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• Setting a timeout for av_read_frame

  20 décembre 2014, par user3663917

  I am new to FFMPEG and was trying to do HLS streaming using FFMPEG. When i tried using the function "av_read_frame" it returns a negative value whenever data is not available. Is there some method to make this function wait till some data is received or to make this function wait till a timeout is reached ?

• Having sound issues while streaming to youtube

  23 septembre 2024, par Hen Simkin

  I created an app that uses rtmp and ffmppeg and youtube api for streaming to youtube,
when i stream and i go to youtube i face sound issues, the sound of the live sounds laggy and robotic.

  


  this is my configuration :

  


  const commonOutputOptions = [
        '-c:v libx264',
        '-c:a aac',
        '-preset veryfast',
        '-crf 30',
        '-b:v 3500k',
        '-b:a 128k',
        '-ac 2',
        '-ar 44100',
        '-g 48',
        '-keyint_min 48',
        '-pix_fmt yuv420p',
        '-x264-params keyint=48:min-keyint=48:scenecut=-1',
        '-flvflags no_duration_filesize',
        '-probesize 32',
        '-analyzeduration 0',
        '-f flv',
    ];


  


  i tried to change it to :

  


  const commonOutputOptions = [
    '-re',  // Enable real-time mode for streaming.
    '-c:v libx264',
    '-c:a aac',
    '-preset veryfast',
    '-crf 23',  // Improved quality setting.
    '-b:v 4500k',  // Adjusted bitrate for better quality.
    '-b:a 160k',  // Higher audio bitrate.
    '-ac 2',
    '-ar 48000',  // Updated sample rate.
    '-g 48',
    '-keyint_min 48',
    '-pix_fmt yuv420p',
    '-x264-params keyint=48:min-keyint=48:scenecut=-1',
    '-flvflags no_duration_filesize',
    '-f flv',
    '-movflags +faststart',  // Improved streaming compatibility.
];


  


  and to this :

  


  const commonOutputOptions = [
    '-c:v libx264',
    '-c:a aac',
    '-preset veryfast',
    '-crf 30',
    '-b:v 3500k',
    '-b:a 128k',
    '-ac 2',
    '-ar 48000', // Updated sampling rate
    '-g 48',
    '-keyint_min 48',
    '-pix_fmt yuv420p',
    '-x264-params keyint=48:min-keyint=48:scenecut=-1',
    '-flvflags no_duration_filesize',
    '-f flv',
];


  


  i tried differnt configurations and nothing makes the sound normal.

  


  when i stream to facebook and twitch the sound is perfect.

  


• ARM compiler update

  15 janvier 2010, par Mans — ARM, Compilers

  Since my last shootout, all the tested vendors have updated their compilers. Here is a quick update on each of them.

  Both the 4.3 and 4.4 branches of FSF GCC have had bugfix releases, bringing them to 4.3.4 and 4.4.2, respectively. Neither update contains anything particularly noteworthy.

  The CodeSourcery 2009q3 release sees an update to a GCC 4.4 base, a significant change from the 4.3 base used in 2009q1. The update is a mixed blessing. In fact, it is mostly a curse and hardly a blessing at all. On the bright side, the floating-point speed regressions in 2009q1 are gone, 2009q3 being a few per cent faster even than 2007q3. Unfortunately, this improvement is completely overshadowed by a major speed regression on integer code, a whopping 24% in one case. This ties in with the slowdown previously observed with FSF GCC 4.4 compared to 4.3.

  ARM RVCT 4.0 is now at Build 697. This update fixes some bugs and introduces others. Notably, it no longer builds FFmpeg correctly. The issue has been reported to ARM.

  Texas Instruments, finally, have made a formal release, v4.6.1, of their TMS470 compiler incorporating various fixes allowing it to build a moderately patched FFmpeg. The performance remains somewhere between GCC and RVCT on average.

  In light of the above, my recommendations remain unchanged :

  • For a free compiler, choose CodeSourcery 2009q1. It beats GCC 4.3.4 by 5-10% in most cases.
  • GNU purists are best served by GCC 4.3.4, which is up to 20% faster than 4.4.2 and rarely slower.
  • When price is not a concern, ARM RCVT is a good option, outperforming GCC by up to a factor 2.
  • In all cases, disable any auto-vectorisation features.

  Regardless of which compiler is chosen, I cannot overstress the importance of testing. All compilers are crawling with bugs, and even the most innocent-looking code change can trigger one of them. When using a compiler other than GCC, extra caution is advised considering a lot of code is developed using only GCC and may thus fall prey to bugs unique to said other compiler.