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• Fail to set profile to high when using ffmpeg with libx264

  10 mars 2012, par user1258095

  Here is my command :

  ffmpeg -i input.avi -vcodec libx264 -vpre fast -vpre high -acodec copy output.avi

  The output :

  Input #0, avi, from 'short.avi':
  
    Metadata:
  
      encoder         : Lavf53.3.0
  
    Duration: 00:00:25.04, start: 0.000000, bitrate: 12705 kb/s
  
      Stream #0.0: Video: msmpeg4v2, yuv420p, 1920x1080, 24 tbr, 24 tbn, 24 tbc
  
      Stream #0.1: Audio: aac, 48000 Hz, 5.1, s16, 316 kb/s
  
      Metadata:
  
        title           : ED-CM-5.1-DVD-Final2
  
  File for preset 'high' not found

  However, I am able to successfully transcode files when setting the profile to baseline or main, from the man page of x264 it is clear that "high" should also be a valid argument. I also want to know where these preset files are located in the file system(I am running ubuntu 11.10) so that I can make sure what arguments I can actually use for presets and profiles at the moment. I am very frustrated by this issue and would really appreciate any input from you guys. Thanks in advance.

• php stream any mp4

  3 avril 2012, par GRaecuS

  I'm developing a web app that converts videos and allows to play them through Flowplayer.

  On the current status, I use ffmpeg to convert the videos to mp4 and qtfaststart to fix their metadata for streaming. Everything is working smoothly as I can download any converted mp4 and view it correctly.

  For serving the videos to Flowplayer, I use a php file which contains the following (summarized) code :

  header("Content-Type: {$mediatype}");
  
  
  
  if ( empty($_SERVER['HTTP_RANGE']) )
  
  {
  
      if ( $filetype == 'flv' && $seekPos != 0 )
  
      {
  
          header("Content-Length: " . ($filesize + 13));
  
          print('FLV');
  
          print(pack('C', 1));
  
          print(pack('C', 1));
  
          print(pack('N', 9));
  
          print(pack('N', 9));
  
      }
  
      else
  
      {           
  
          header("Content-Length: {$filesize}");
  
      }
  
  
  
      $fh = fopen($filepath, "rb") or die("Could not open file: {$filepath}");
  
  
  
      # seek to requested file position
  
      fseek($fh, $seekPos);
  
  
  
      # output file
  
      while(!feof($fh))
  
      {
  
          # output file without bandwidth limiting
  
          echo fread($fh, $filesize);
  
      }
  
      fclose($fh);
  
  }
  
  else //violes rfc2616, which requires ignoring  the header if it's invalid
  
  {   
  
      $fp = @fopen($file, 'rb');
  
  
  
      $size   = filesize($file); // File size
  
      $length = $size;           // Content length
  
      $start  = 0;               // Start byte
  
      $end    = $size - 1;       // End byte
  
      // Now that we've gotten so far without errors we send the accept range header
  
      /* At the moment we only support single ranges.
  
       * Multiple ranges requires some more work to ensure it works correctly
  
       * and comply with the spesifications: http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
  
       *
  
       * Multirange support annouces itself with:
  
       * header('Accept-Ranges: bytes');
  
       *
  
       * Multirange content must be sent with multipart/byteranges mediatype,
  
       * (mediatype = mimetype)
  
       * as well as a boundry header to indicate the various chunks of data.
  
       */
  
      header("Accept-Ranges: 0-$length");
  
      // header('Accept-Ranges: bytes');
  
      // multipart/byteranges
  
      // http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
  
      if (isset($_SERVER['HTTP_RANGE']))
  
      {
  
          $c_start = $start;
  
          $c_end   = $end;
  
          // Extract the range string
  
          list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
  
          // Make sure the client hasn't sent us a multibyte range
  
          if (strpos($range, ',') !== false)
  
          {
  
              // (?) Shoud this be issued here, or should the first
  
              // range be used? Or should the header be ignored and
  
              // we output the whole content?
  
              header('HTTP/1.1 416 Requested Range Not Satisfiable');
  
              header("Content-Range: bytes $start-$end/$size");
  
              // (?) Echo some info to the client?
  
              exit;
  
          }
  
          // If the range starts with an '-' we start from the beginning
  
          // If not, we forward the file pointer
  
          // And make sure to get the end byte if spesified
  
          if ($range0 == '-')
  
          {
  
  
  
              // The n-number of the last bytes is requested
  
              $c_start = $size - substr($range, 1);
  
          }
  
          else
  
          {
  
              $range  = explode('-', $range);
  
              $c_start = $range[0];
  
              $c_end   = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $size;
  
          }
  
          /* Check the range and make sure it's treated according to the specs.
  
           * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
  
           */
  
          // End bytes can not be larger than $end.
  
          $c_end = ($c_end > $end) ? $end : $c_end;
  
          // Validate the requested range and return an error if it's not correct.
  
          if ($c_start > $c_end || $c_start > $size - 1 || $c_end >= $size)
  
          {
  
              header('HTTP/1.1 416 Requested Range Not Satisfiable');
  
              header("Content-Range: bytes $start-$end/$size");
  
              // (?) Echo some info to the client?
  
              exit;
  
          }
  
          $start  = $c_start;
  
          $end    = $c_end;
  
          $length = $end - $start + 1; // Calculate new content length
  
          fseek($fp, $start);
  
          header('HTTP/1.1 206 Partial Content');
  
      }
  
  
  
      // Notify the client the byte range we'll be outputting
  
      header("Content-Range: bytes $start-$end/$size");
  
      header("Content-Length: $length");
  
  
  
      // Start buffered download
  
      $buffer = 1024 * 8;
  
      while(!feof($fp) && ($p = ftell($fp)) <= $end)
  
      {
  
          if ($p + $buffer > $end)
  
          {
  
              // In case we're only outputtin a chunk, make sure we don't
  
              // read past the length
  
              $buffer = $end - $p + 1;
  
          }
  
          set_time_limit(0); // Reset time limit for big files
  
          echo fread($fp, $buffer);
  
          flush(); // Free up memory. Otherwise large files will trigger PHP's memory limit.
  
      }
  
  
  
      fclose($fp);
  
  }

  Unfortunately, it is working only for the majority of the videos. For some of them, Flowplayer keeps returning Error 200, even though they were encoded correctly.

  How can I fix this ? Is it a coding problem or those videos are faulty ?

• c++, FFMPEG, H264, creating zero-delay stream

  5 février 2015, par Mat

  I’m trying to encode video (using h264 codec at the moment, but other codecs would be fine too if better suited for my needs) such that the data needed for decoding is available directly after a frame (including the first frame) was encoded (so, i want only I and P frames, no B frames).

  How do I need to setup the AVCodecContext to get such a stream ? So far my testing arround with the values still always resulted in avcodec_encode_video() returning 0 on the first frame.

  //edit : this is currently my setup code of the AVCodecContext :

  static AVStream* add_video_stream(AVFormatContext *oc, enum CodecID codec_id, int w, int h, int fps)
  
  {
  
      AVCodecContext *c;
  
      AVStream *st;
  
      AVCodec *codec;
  
  
  
      /* find the video encoder */
  
      codec = avcodec_find_encoder(codec_id);
  
      if (!codec) {
  
          fprintf(stderr, "codec not found\n");
  
          exit(1);
  
      }
  
  
  
      st = avformat_new_stream(oc, codec);
  
      if (!st) {
  
          fprintf(stderr, "Could not alloc stream\n");
  
          exit(1);
  
      }
  
  
  
      c = st->codec;
  
  
  
      /* Put sample parameters. */
  
      c->bit_rate = 400000;
  
      /* Resolution must be a multiple of two. */
  
      c->width    = w;
  
      c->height   = h;
  
      /* timebase: This is the fundamental unit of time (in seconds) in terms
  
       * of which frame timestamps are represented. For fixed-fps content,
  
       * timebase should be 1/framerate and timestamp increments should be
  
       * identical to 1. */
  
      c->time_base.den = fps;
  
      c->time_base.num = 1;
  
      c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
  
  
      c->codec = codec;
  
      c->codec_type = AVMEDIA_TYPE_VIDEO;
  
      c->coder_type = FF_CODER_TYPE_VLC;
  
      c->me_method = 7; //motion estimation algorithm
  
      c->me_subpel_quality = 4;
  
      c->delay = 0; 
  
      c->max_b_frames = 0; 
  
      c->thread_count = 1; // more than one threads seem to increase delay
  
      c->refs = 3;
  
  
  
      c->pix_fmt       = PIX_FMT_YUV420P;
  
  
  
      /* Some formats want stream headers to be separate. */
  
      if (oc->oformat->flags & AVFMT_GLOBALHEADER)
  
          c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      return st;
  
  }

  but with this avcodec_encode_video() will buffer 13 frames before returning any bytes (after that, it will return bytes on every frame). if I set gop_size to 0, then avcodec_encode_video() will return bytes only after the second frame was passed to it. I need a zero delay though.

  This guy apparently was successful (even with larger gop) : http://mailman.videolan.org/pipermail/x264-devel/2009-May/005880.html but I don’t see what he is doing differently