Recherche avancée

Sur d’autres sites (10394)

• avcodec/apedec : Fix several integer overflows in predictor_update_filter() and do_app...

  2 septembre 2019, par Michael Niedermayer

  avcodec/apedec : Fix several integer overflows in predictor_update_filter() and do_apply_filter()
  Fixes : negation of -2147483648 cannot be represented in type 'int' ; cast to an unsigned type to negate this value to itself
  
  Fixes : signed integer overflow : -14527961 - 2147483425 cannot be represented in type 'int'
  
  Fixes : 16380/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5645957131141120
  
  Fixes : 16968/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5716169901735936
  
  Fixes : 17074/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5198710497083392
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/apedec.c

• rtpdec : fix issue with conversion from unsigned to signed

  20 février 2015, par Gilles Chanteperdrix

  rtpdec : fix issue with conversion from unsigned to signed
  When receiving an RTCP packet, the difference between the last RTCP
  
  timestamp and the base timestamp may be negative. As these timestamps
  
  are of the uint32_t type, the result becomes a large integer. Cast
  
  the difference to int32_t to avoid this issue.
  The result of this issue is very large start times for RTSP
  
  streams, and difficulty to restart correctly after a pause.
  Signed-off-by : Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] libavformat/rtpdec.c

• create bar type wave forms using ffmpeg

  8 juillet 2016, par Ashish Joshi

  i am trying to create wave forms from mp3 using ffmpeg.
  i have successfully created waveforms like below

  

  now i am having troubles with generating like below sample image...

  

  the code i am using to generate vertical line is provided below...

  while (!feof($handle) && $data_point < $data_size) {
  
              if ($data_point++ % DETAIL == 0) {
  
                  $bytes = array();
  
  
  
                  // get number of bytes depending on bitrate
  
                  for ($i = 0; $i < $byte; $i++) {
  
                      $bytes[$i] = fgetc($handle);
  
                  }
  
  
  
                  switch ($byte) {
  
                  // get value for 8-bit wav
  
                  case 1:
  
                      $data = findValues($bytes[0], $bytes[1]);
  
                      break;
  
                  // get value for 16-bit wav
  
                  case 2:
  
                      if (ord($bytes[1]) & 128) {
  
                          $temp = 0;
  
                      } else {
  
                          $temp = 128;
  
                      }
  
  
  
                      $temp = chr((ord($bytes[1]) & 100) + $temp);
  
                      $data = floor(findValues($bytes[0], $temp) / 256);
  
                      break;
  
                  }
  
  
  
                  // skip bytes for memory optimization
  
                  fseek($handle, $ratio, SEEK_CUR);
  
  
  
                  // draw this data point
  
                  // relative value based on height of image being generated
  
                  // data values can range between 0 and 255
  
                  $v = (int) ($data / 255 * $height);
  
  
  
                  // don't print flat values on the canvas if not necessary
  
                  if (!($v / $height == 0.5 && !$draw_flat))
  
                  // draw the line on the image using the $v value and centering it vertically on the canvas
  
                  {
  
                      imageline($img,
  
                          // x1
  
                          (int) ($data_point / DETAIL),
  
                          // y1: height of the image minus $v as a percentage of the height for the wave amplitude
  
                          $height * $wav - $v,
  
                          // x2
  
                          (int) ($data_point / DETAIL),
  
                          // y2: same as y1, but from the bottom of the image
  
                          $height * $wav - ($height - $v), imagecolorallocate($img, $r, $g, $b));
  
                  }
  
  
  
                  imageline($img1,
  
                      // x1
  
                      (int) ($data_point / DETAIL),
  
                      // y1: height of the image minus $v as a percentage of the height for the wave amplitude
  
                      $height * $wav - $v,
  
                      // x2
  
                      (int) ($data_point / DETAIL),
  
                      // y2: same as y1, but from the bottom of the image
  
                      $height * $wav - ($height - $v), imagecolorallocate($img1, $r1, $g1, $b1));
  
  
  
              }

  any help is appreciated...