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• aacenc : implement Intensity Stereo encoding support

  2 juillet 2015, par Rostislav Pehlivanov

  aacenc : implement Intensity Stereo encoding support
  This commit implements intensity stereo coding support
  
  to the native aac encoder. This is a way to increase the efficiency
  
  of the encoder by zeroing the right channel’s spectral coefficients
  
  (in a channel pair) and rederiving them in the decoder using information
  
  from the scalefactor indices of special band types. This commit
  
  confomrs to the official ISO 13818-7 specifications, although due to
  
  their ambiguity certain deviations have been taken to ensure maximum
  
  sound quality. This commit has been extensively tested and has shown
  
  to not result in audiable audio artifacts unless in extreme cases.
  
  This commit also adds an option, aac_is, which has the value of
  
  0 by default. Intensity Stereo is part of the scalable aac profile
  
  and is thus non-default.
  The way IS coding works is that it rederives the right channel’s
  
  spectral coefficients from the left channel via the scalefactor
  
  index values left in the right channel. Since an entire band’s
  
  spectral coefficients do not need to be coded, the encoder’s
  
  efficiency jumps up and it unzeroes some high frequency values
  
  which it previously did not have enough bits to encode. That way
  
  less information is lost than the information lost by rederiving
  
  the spectral coefficients with some error. This is why the
  
  filesize of files encoded with IS do not decrease significantly.
  
  Users wishing that IS coding should reduce filesize are expected
  
  to reduce their encoding bitrates appropriately.
  This is V2 of the commit. The old version did not mark ms_mask as
  
  0 since M/S and IS coding are incompactible, which resulted in
  
  distortions with M/S coding enabled. This version also improves
  
  phase detection by measuring it for every spectral coefficient in
  
  the band and using a simple majority rule to determine whether the
  
  coefficients are in or out of phase. Also, the energy values per
  
  spectral coefficient were changed as to reflect the
  
  official specifications.
  Reviewed-by : Claudio Freire <klaussfreire@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/aaccoder.c
  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/aacenc.h

• where is this wrong in ffmpeg installation and php configuration

  23 juillet 2015, par sonam Sharma

  hello all i have successfully installed ffmpeg to my computer i can check it by checking ffmpeg-version it returns something logical.

  which means the ffmpeg is running successfully on my pac but when i run this code by php i get error in ffmpeg loading

  <?php
  
   extension_loaded('ffmpeg') or die('Error in loading ffmpeg'); 
  
   // Determine the full path for our video
  
    $vid = realpath('./test/Sample.mp4');
  
  
  
   // Create the ffmpeg instance and then display the information about the video clip.
  
   $ffmpegInstance = new ffmpeg_movie($vid);
  
   echo "getDuration: " . $ffmpegInstance->getDuration() . "<br />".
  
    "getFrameCount: " . $ffmpegInstance->getFrameCount() . "<br />".
  
     "getFrameRate: " . $ffmpegInstance->getFrameRate() . "<br />".
  
     "getFilename: " . $ffmpegInstance->getFilename() . "<br />".
  
      "getComment: " . $ffmpegInstance->getComment() . "<br />".
  
     "getTitle: " . $ffmpegInstance->getTitle() . "<br />".
  
     "getAuthor: " . $ffmpegInstance->getAuthor() . "<br />".
  
          "getCopyright: " . $ffmpegInstance->getCopyright() . "<br />".
  
       "getArtist: " . $ffmpegInstance->getArtist() . "<br />".
  
       "getGenre: " . $ffmpegInstance->getGenre() . "<br />".
  
       "getTrackNumber: " . $ffmpegInstance->getTrackNumber() . "<br />".
  
      "getYear: " . $ffmpegInstance->getYear() . "<br />".
  
    "getFrameHeight: " . $ffmpegInstance->getFrameHeight() . "<br />". 
  
       "getAudioChannels: " . $ffmpegInstance->getAudioChannels() . "<br />".
  
     "hasAudio: " . $ffmpegInstance->hasAudio();
  
        ?>

  please tell me where i am doing wrong

• LIVE555 RTSP H.264 Raw Video File Stream - ffplay Errors

  22 octobre 2015, par Chris.

  I am streaming a raw .h264 video file via RTSP using LIVE555.

  To receive the stream I am using ffplay. However, when watching the video I notice bad video quality and a bunch of errors in the ffplay-console :

  Input #0, rtsp, from 'rtsp://xx.xx.xxx.x/stream': sq=    0B f=0/0
  
    Metadata:
  
      title           : stream
  
      comment         : stream
  
  Duration: N/A, start: 0.099989, bitrate: N/A
  
      Stream #0:0: Video: h264 (High), yuv420p(tv, smpte170m/smpte170m/bt470m), 16
  
  80x1050 [SAR 1:1 DAR 8:5], 60 fps, 60 tbr, 90k tbn, 120 tbc
  
  [h264 @ 03f92100] RTP: missed 46 packetsq=   28KB sq=    0B f=1/1
  
  [h264 @ 03f92100] RTP: missed 74 packetsq=   23KB sq=    0B f=1/1
  
  [h264 @ 03f92100] RTP: missed 43 packets
  
  [h264 @ 03f92100] RTP: missed 35 packetsq=  179KB sq=    0B f=1/1
  
  [h264 @ 05710640] left block unavailable for requested intra4x4 mode -1 at 0 38
  
  [h264 @ 05710640] error while decoding MB 0 38, bytestream 48108
  
  [h264 @ 05710640] Cannot use next picture in error concealment
  
  [h264 @ 05710640] concealing 2989 DC, 2989 AC, 2989 MV errors in P frame
  
  [h264 @ 051043c0] left block unavailable for requested intra4x4 mode -1 at 0 26
  
  [h264 @ 051043c0] error while decoding MB 0 26, bytestream 5894
  
  [h264 @ 051043c0] concealing 4249 DC, 4249 AC, 4249 MV errors in I frame
  
  [h264 @ 03f92100] RTP: missed 68 packetsq=   28KB sq=    0B f=1/1
  
  [h264 @ 03f92100] RTP: missed 31 packetsq=  153KB sq=    0B f=1/1
  
  [h264 @ 052a0020] concealing 3292 DC, 3292 AC, 3292 MV errors in I frame
  
  [h264 @ 052a0020] Cannot use next picture in error concealment1/1
  
  [h264 @ 052a0020] concealing 2190 DC, 2190 AC, 2190 MV errors in P frame
  
  [h264 @ 03f92100] RTP: missed 69 packetsq=   27KB sq=    0B f=1/1
  
  [h264 @ 052a0020] concealing 3732 DC, 3732 AC, 3732 MV errors in I frame
  
  [h264 @ 03f92100] RTP: missed 26 packetsq=   30KB sq=    0B f=1/1
  
  ...

  How can I determine what’s wrong here ? Either with the stream or the file ?