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• Convert mp3 to AAC with mpeg-2 container (FFMPEG)

  18 mars 2016, par jsurf

  I’m trying to convert an mp3 audio file to an AAC file with FFMPEG, and I need the audio to be wrapped in an MPEG-2 container.
  The resulting AAC file needs to be AAC-LC (Low Complexity), 1-channel, CBR mode, 44100 sample rate, and 48kb/s bitrate, so I use this command :

  ffmpeg -y -i input.mp3 -ar 44100 -ab 48k -acodec libfdk_aac -ac 1 output.aac

  But when I examine the ADTS headers, the audio file is always being wrapped in an MPEG-4 container. I have tried all the codecs listed here but I still end up with an mpeg-4 container wrapped around the audio : http://trac.ffmpeg.org/wiki/AACEncodingGuide.

  Here are the headers I get when examining the AAC output file :

  mpeg_type : ’MPEG4’,
  profile : 2,
  profile_name : ’AAC LC’,
  sample_freq : 44100,
  channel_config : 1,
  channels : 1,
  frame_length : 139,
  buffer_fullness : 157,
  number_of_frames : 1,
  frames_per_sec : 43.06640625

  Any ideas as to why ffmpeg wraps an mp4 container around the audio ? Can I get around this somehow ? Are there any other encoders I can try aside from FFMPEG ? I was giving FAAC encoder a shot and it gives me the proper encoding and ADTS headers, but alas it does not support mp3, only WAV.

• Multimedia Exploration Journal : The Past Doesn’t Die

  12 juillet 2011, par Multimedia Mike — Game Hacking

  New haul of games, new (old) multimedia formats.

  Lords of Midnight
  Check out the box copy scan for Lords of Midnight in MobyGames. In particular, I’d like to call your attention to this little blurb :

  
  
  

  Ahem, "Journey through an immense world — the equivalent of 8 CD-ROMs." Yet, when I procured the game, it only came on a single CD-ROM. It’s definitely a CD-ROM (says so on the disc) and, coming from 1995, certainly predates the earliest DVD-ROMs (which can easily store 8 CD-ROMs on a disc). Thus, I wanted to jump in a see if they were using some phenomenal compression in order to squeeze so much info into 600 or so megabytes.

  I was surprised to see the contents of the disc clocking in at just under 40 megabytes. An intro movie and an outro movie account for 75% of that. Format ? None other than that curious ASCII anomaly, ARMovie/RPL with Escape 122 codec data.

  Cyclemania

  
  
  

  Cyclemania is one of those FMV backdrop action games, but with a motorcycle theme. I had a good feeling I would find some odd multimedia artifacts here and the game didn’t disappoint. The videos are apparently handled using 3-4 discrete files per animation. I’ve documented my cursory guesses and linked some samples at the new MultimediaWiki page.

  Interplay ACMP
  This is unrelated to this particular acquistion, but I was contacted today about audio files harvested from the 1993 DOS game Star Trek : Judgment Rites. The files begin with the ASCII signature "Interplay ACMP Data". This reminds me of Interplay MVE files which begin with the similar string "Interplay MVE File". My theory is that these files use the ACOMP compression format, though I’m still trying to make it fit.

  Wiki and samples are available as usual if you’d like to add your own research.

• Concatenating video files with ffmpeg, no sound in output file [on hold]

  1er septembre 2013, par Junaid

  I am concatenating different AVI video files. The input files has been specified in input.txt in the order required. First video file does not have sound track, but subsequent files have.

  After completion the resulting the operation, the output does not have audio !

  If I remove first video files from input then resulting video gets sound. So it means the output format follows the first item in input list. How can I solve this problem.

  Please suggest the options in ffmpeg ; not in any other tools like mencoder.

   ffmpeg -f concat -i inputs.txt -c copy test.avi
  
  ffmpeg version 1.1.git Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun 27 2013 09:22:45 with gcc 4.7 (Ubuntu/Linaro 4.7.3-1ubuntu1)
  
    configuration: --prefix=/home/junaid/ffmpeg_build --extra-cflags=-I/home/junaid/ffmpeg_build/include --extra-ldflags=-L/home/junaid/ffmpeg_build/lib --bindir=/home/junaid/bin --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-x11grab
  
    libavutil      52. 37.101 / 52. 37.101
  
    libavcodec     55. 17.100 / 55. 17.100
  
    libavformat    55.  9.100 / 55.  9.100
  
    libavdevice    55.  2.100 / 55.  2.100
  
    libavfilter     3. 77.101 /  3. 77.101
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  3.100 / 52.  3.100
  
  [concat @ 0x335a880] Invalid stream index 1
  
  [concat @ 0x335a880] max_analyze_duration 5000000 reached at 5000000 microseconds
  
  Input #0, concat, from 'inputs.txt':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: mpeg4 (Advanced Simple Profile) (xvid / 0x64697678), yuv420p, 720x480 [SAR 32:27 DAR 16:9], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
  Output #0, avi, to 'test.avi':
  
    Metadata:
  
      ISFT            : Lavf55.9.100
  
      Stream #0:0: Video: mpeg4 (xvid / 0x64697678), yuv420p, 720x480 [SAR 32:27 DAR 16:9], q=2-31, 25 fps, 25 tbn, 25 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 6368 times
  
  frame= 3793 fps=0.0 q=-1.0 size=   11108kB time=00:02:37.96 bitrate= 576.1kbits/Invalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 7173 times
  
  frame= 7921 fps=7801 q=-1.0 size=   22928kB time=00:05:30.16 bitrate= 568.9kbitsInvalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 6614 times
  
  frame=11729 fps=7688 q=-1.0 size=   27057kB time=00:08:08.96 bitrate= 453.3kbitsInvalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 6247 times
  
  frame=15324 fps=7565 q=-1.0 size=   44956kB time=00:10:38.92 bitrate= 576.4kbitsInvalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 6553 times
  
  frame=19096 fps=7516 q=-1.0 size=   64014kB time=00:13:16.24 bitrate= 658.6kbitsInvalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 6753 times
  
  frame=22983 fps=7558 q=-1.0 size=   79848kB time=00:15:58.36 bitrate= 682.5kbitsInvalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 7011 times
  
  frame=27019 fps=7610 q=-1.0 size=   94130kB time=00:18:46.68 bitrate= 684.4kbitsInvalid stream index 1
  
  [concat @ 0x335a880] Invalid stream index 1
  
      Last message repeated 1302 times
  
  frame=27772 fps=7658 q=-1.0 Lsize=   96618kB time=00:19:18.08 bitrate= 683.5kbits/s    
  
  video:95921kB audio:0kB subtitle:0 global headers:0kB muxing overhead 0.726908%