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• hls av_read_frame delay reading between segment files

  12 septembre 2016, par Debendra Modi

  I am trying to demux live HLS audio and find delays in the loop for reading frames whenever it starts reading the next segment file.

  The HLS audio segment files are MP3, 1 second target duration. Each 1 second file has 13 frames.

  The live HLS source and our code is started at the same time. avformat_open_input takes about 5 seconds to return, as it waits for 3 segment files as required by HLS standards.

  The av_read_frame loop reads 13 frames from each segment file and then it takes about 1.5 to 2 seconds before it starts reading the next 13 frames from the next segment file. Our interrupt callback is called several times within this duration and we return a 0 to continue reading.

  The playlist has several segment files available for it to read so it is not waiting for the segment file to be available in the playlist.

  Given below is the code snippet and attached is the m3u8.

  static int interrupt_cb(void *start_ticks) 
  
  {
  
  long starttime = (long)start_ticks;  //the start time ticks is in opaque
  
  
  
      //timeout after 5 seconds of no activity
  
      if (GetTickCount() - starttime  >7000))
  
              return 1;
  
      log("Returning 0");
  
      return 0;
  
  } 
  
  
  
  
  
  static bool hls_demuxer( char* fileName )
  
  {
  
      AVDictionary *options = NULL;
  
      av_dict_set(&options, "analyzeduration", "100000", 0);
  
  
  
      AVFormatContext* formatContext = avformat_alloc_context( );
  
  
  
      formatContext->interrupt_callback.callback = interrupt_cb;
  
      long startticks = GetTickCount();
  
      formatContext->interrupt_callback.opaque = (void*) startticks;
  
      formatContext->flags|=AVFMT_FLAG_NONBLOCK;
  
  
  
      //added the following additional parameters to see if they would help to     speed up reading frames - but in vain
  
  
  
      formatContext->probesize = 2048;
  
      formatContext->max_delay = 100000; //0.1 secs, default 5 secs
  
      formatContext->probe_score = 100;
  
      formatContext->max_analyze_duration = 100000;   //0.1 secs
  
  
  
      if ( avformat_open_input( &formatContext, fileName, NULL, NULL ) !=0 )
  
      {
  
          return false;
  
      }
  
      av_dict_free(&options);
  
  
  
  
  
      av_dump_format(formatContext,0,filename,0);             //reaches here after 4 secs of start. Interrupt callback called several times.  This is OK.
  
  
  
      if (avformat_find_stream_info(formatContext,NULL) != 0)
  
          return false;
  
  
  
      AVPacket pkt;
  
      while(!threadstop)
  
      {   
  
  
  
  startticks = GetTickCount();
  
  
  
  
  
   //**THIS IS THE ISSUE** ->reads 13 frames from first segment file.
  
   // No interrupt callback.  Then before using the next segment file, calls 
  
  //interrupt callback several times (about 1 to 2 secs) before reading next 
  
  //segment file, then reads the next 13 frames.  Playlist has several files 
  
  //available.  This continues between each segment file read, thereby     
  
  //delaying read for each new segment file in playlist.
  
  
  
  if (av_read_frame(formatContext,&pkt) != 0)         
  
      return false;                       
  
  
  
          log("Packet read");
  
      //Do something with packet
  
          av_packet_unref(&pkt);                      
  
      }
  
      return true;    //When the playlist ends, it has 38 files.The demuxer Takes over 30 seconds longer.
  
  }

  Any suggestions ? Thanks in advance.

• Merge commit ’3fb29588a27a711132106b924e27b53789a58dcb’

  17 mai 2013, par Michael Niedermayer

  Merge commit ’3fb29588a27a711132106b924e27b53789a58dcb’
  * commit ’3fb29588a27a711132106b924e27b53789a58dcb’ :
  
    vf_drawtext : don’t leak the expressions.
  
    vf_crop : make config_props work properly when called multiple times.
  
    vf_setdar : make config_props work properly when called multiple times.
  Conflicts :
  
  	libavfilter/vf_aspect.c
  
  	libavfilter/vf_drawtext.c
  Merged-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavfilter/vf_aspect.c
  • [DH] libavfilter/vf_crop.c
  • [DH] libavfilter/vf_drawtext.c

• Is it possible to install SoX on XAMPP ?

  6 juin 2012, par Jānis Lazda-Lazdiņš

  I am having hard times finding a way to get SoX working on my Windows Xampp server. I have FFMpeg working which does it's job, but I need also SoX for audio managing.
  I have installed SoX on my machine and it looks like it works with some sample .bat files, but I want to execute SoX commands from php file, just like FFMpeg.

  The command I want to execute is pretty simple two audio file combination :
  $ sox -m audio1.wav audio2.wav output.wav

  I would appreciate any help.