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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.

• Unable to link QtFFmpegWrapper sample on Win7 with VS 2012

  20 juillet 2014, par mschwarz

  I am trying to incorporate QtFFmpegWrapper in my program, but both my program and the provided sample won’t link with ffmpeg :

  QVideoEncoder.obj:-1: Error: LNK2019: unresolved external symbol _avcodec_init referenced in function "protected: bool __thiscall QVideoEncoder::initCodec(void)" (?initCodec@QVideoEncoder@@IAE_NXZ)
  
  QVideoDecoder.obj:-1: Error: LNK2001: unresolved external symbol _avcodec_init
  
  QVideoEncoder.obj:-1: Error: LNK2019: unresolved external symbol _avcodec_thread_init referenced in function "public: bool __thiscall QVideoEncoder::createFile(class QString,unsigned int,unsigned int,unsigned int,unsigned int,unsigned int)" (?createFile@QVideoEncoder@@QAE_NVQString@@IIIII@Z)
  
  QVideoEncoder.obj:-1: Error: LNK2019: unresolved external symbol _avcodec_open referenced in function "public: bool __thiscall QVideoEncoder::createFile(class QString,unsigned int,unsigned int,unsigned int,unsigned int,unsigned int)" (?createFile@QVideoEncoder@@QAE_NVQString@@IIIII@Z)

  and 10 or so more like these ...

  Why do these pop up when linking ? The libs are all there and found, it just seems like the linker has issues with them ...

  I use the following setup for my project :

  • Latest QtFFmpegWrapper from https://code.google.com/p/qtffmpegwrapper/
  • qt-opensource-windows-x86-msvc2012_opengl-5.3.0
  • Visual Studio 2012 Professional
  • Qt Creator 3.1.2
  • ffmpeg builds from http://ffmpeg.zeranoe.com/builds/ :
  • ffmpeg-20140717-git-fa6716c-win32-dev
  • ffmpeg-20140717-git-fa6716c-win32-shared

  Everything is 32Bit.