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Thread: Is there a difference between faac and libfaac?

  1. #1
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    Question Is there a difference between faac and libfaac?

    Hi
    Is there a difference between faac and libfaac?

    I have an iPod Shuffle.
    One of these:-



    It plays m4a tracks created using faac encoder.
    Like this:-
    Code:
    ffmpeg -i foo.flac -f wav - | faac -o test1.m4a -b 152 -
    But it won't play tracks created using libfaac.
    Like this:-
    Code:
    ffmpeg -i foo.flac -acodec libfaac -ab 152k test2.m4a
    I've compared the MediaInfo for the two files.
    They look very similar, faac does a more thorough job of tagging.

    Does ffmpeg do something to the file when it's converting or muxing with libfaac to make it unplayable by the Shuffle?

    I've uploaded the two files.
    test1.m4a is created using faac
    test2.m4a is created using libfaac
    They are here:- http://www.mediafire.com/?womxhbv26tk5298

    What's the difference?


    Using Ubuntu Karmic 9.10
    and
    FAAC 1.26.1
    and
    FFmpeg version git-N-28456-g1c31b26

  2. #2
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    Re: Is there a difference between faac and libfaac?

    FFmpeg shows some additional differences:
    Code:
    $ ffmpeg -i test1.m4a
    FFmpeg version git-N-55253-g2da715c, Copyright (c) 2000-2011 the FFmpeg developers
      built on Mar 22 2011 10:47:21 with gcc 4.5.2 20110127 (prerelease)
      configuration: --prefix=/usr/local --enable-gpl --enable-nonfree --enable-libfaac --enable-libmp3lame --enable-libx264 --enable-x11grab
      libavutil    50. 40. 0 / 50. 40. 0
      libavcodec   52.114. 0 / 52.114. 0
      libavformat  52.103. 0 / 52.103. 0
      libavdevice  52.  3. 0 / 52.  3. 0
      libavfilter   1. 76. 0 /  1. 76. 0
      libswscale    0. 12. 0 /  0. 12. 0
      libpostproc  51.  2. 0 / 51.  2. 0
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test1.m4a':
      Metadata:
        major_brand     : mp42
        minor_version   : 0
        compatible_brands: mp42isom
        creation_time   : 2011-03-22 16:04:14
        encoder         : FAAC 1.26.1 (Aug 16 2008) UNSTABLE
      Duration: 00:04:01.56, start: 0.023220, bitrate: 153 kb/s
        Stream #0.0(eng): Audio: aac, 44100 Hz, stereo, s16, 151 kb/s
        Metadata:
          creation_time   : 2011-03-22 16:04:14
    At least one output file must be specified
    
    $ ffmpeg -i test2.m4a
    FFmpeg version git-N-55253-g2da715c, Copyright (c) 2000-2011 the FFmpeg developers
      built on Mar 22 2011 10:47:21 with gcc 4.5.2 20110127 (prerelease)
      configuration: --prefix=/usr/local --enable-gpl --enable-nonfree --enable-libfaac --enable-libmp3lame --enable-libx264 --enable-x11grab
      libavutil    50. 40. 0 / 50. 40. 0
      libavcodec   52.114. 0 / 52.114. 0
      libavformat  52.103. 0 / 52.103. 0
      libavdevice  52.  3. 0 / 52.  3. 0
      libavfilter   1. 76. 0 /  1. 76. 0
      libswscale    0. 12. 0 /  0. 12. 0
      libpostproc  51.  2. 0 / 51.  2. 0
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test2.m4a':
      Metadata:
        major_brand     : M4A 
        minor_version   : 512
        compatible_brands: isomiso2
        creation_time   : 1970-01-01 00:00:00
        encoder         : Lavf52.103.0
      Duration: 00:04:01.58, start: 0.000000, bitrate: 154 kb/s
        Stream #0.0(und): Audio: aac, 44100 Hz, stereo, s16, 151 kb/s
        Metadata:
          creation_time   : 1970-01-01 00:00:00
    At least one output file must be specified

  3. #3
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    Re: Is there a difference between faac and libfaac?

    Quote Originally Posted by FakeOutdoorsman View Post
    FFmpeg shows some additional differences:
    Thanks.

    OK
    I've just ran the command again with some instructions to change the metadata.
    Code:
    ffmpeg -i foo.flac -acodec libfaac -ab 152k -metadata major_brand="mp42" -metadata minor_version="0" -metadata Title="whatever" -metadata encoder="FAAC 1.26.1 (Aug 16 2008) UNSTABLE" -metadata compatible_brands="mp42isom" test97.m4a
    It's changed the Title OK, but ffmpeg has ignored the ones that matter.

    Any ideas what to do next?

    Code:
    ron@ubuntu:~$ ffprobe test97.m4a
    FFprobe version git-N-28456-g1c31b26, Copyright (c) 2007-2011 the FFmpeg developers
      built on Mar 15 2011 20:38:57 with gcc 4.4.1
      configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-pthreads --enable-libfaac --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-x11grab --disable-encoder=vorbis
      libavutil    50. 39. 0 / 50. 39. 0
      libavcodec   52.114. 0 / 52.114. 0
      libavformat  52.103. 0 / 52.103. 0
      libavdevice  52.  3. 0 / 52.  3. 0
      libavfilter   1. 76. 0 /  1. 76. 0
      libswscale    0. 12. 0 /  0. 12. 0
      libpostproc  51.  2. 0 / 51.  2. 0
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test97.m4a':
      Metadata:
        major_brand     : M4A 
        minor_version   : 512
        compatible_brands: isomiso2
        creation_time   : 1970-01-01 00:00:00
        title           : whatever
        encoder         : Lavf52.103.0
      Duration: 00:04:01.58, start: 0.000000, bitrate: 154 kb/s
        Stream #0.0(und): Audio: aac, 44100 Hz, stereo, s16, 151 kb/s
        Metadata:
          creation_time   : 1970-01-01 00:00:00

  4. #4
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    Re: Is there a difference between faac and libfaac?

    Quote Originally Posted by ron999 View Post
    Any ideas what to do next?
    Not any good ideas. Maybe the iPod would work with a different output format? Perhaps you could try .aac or .mp4 instead of .m4a. You could also investigate the -atag option, but I'm not very familiar with that or if it would be useful at all.

  5. #5
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    Re: Is there a difference between faac and libfaac?

    Quote Originally Posted by FakeOutdoorsman View Post
    ... Maybe the iPod would work with a different output format? Perhaps you could try .aac or .mp4 instead of .m4a. You could also investigate the -atag option,..
    Hi
    I've tried those other two formats.
    gtkpod won't let me load aac (unrecognized format).
    And the file in mp4 format still won't play when encoded with libfaac.

    The atag option is in the ffmpeg documentation, but there's not much information so I don't know which atag formats to try.

    In the meantime...
    I've found that if I load the non-playing file into EasyTAG-aac v.2.1.5 then change one or more of the fields (any of them) such as changing the filename etc, then SAVE changes and exit. Then the file will load and play OK on the iPod. Go figure!


    EasyTAG puts in some meta information, not just for the changed field.
    I've tried messing with AtomicParsley to do the same as EasyTAG does.
    I can set them just the same, but it still won't play.

    So it looks like EasyTAG is doing something magical to the metadata/atoms - but I don't know what it is.
    Perhaps ffmpeg/libfaac create the metadata differently that's unfriendly with this particular model of iPod.

    This is the MediaInfo from test2.m4a when I've renamed it test3.m4a using EasyTAG.
    Notice all the extra fields, though all I did was change the filename and save and exit.

    Code:
    Complete name                    : test3.m4a
    Format                           : MPEG-4
    Format profile                   : Apple audio with iTunes info
    Codec ID                         : M4A 
    File size                        : 4.46 MiB
    Duration                         : 4mn 1s
    Overall bit rate                 : 155 Kbps
    Part/Position                    : 0
    Part/Total                       : 0
    Track name/Position              : 0
    Track name/Total                 : 0
    Tagged date                      : UTC 2011-03-23 20:45:18
    Writing application              : Lavf52.103.0
    Cover                            : Yes
    
    Audio
    ID                               : 1
    Format                           : AAC
    Format/Info                      : Advanced Audio Codec
    Format profile                   : LC
    Codec ID                         : 40
    Duration                         : 4mn 1s
    Bit rate mode                    : Variable
    Bit rate                         : 152 Kbps
    Maximum bit rate                 : 204 Kbps
    Channel(s)                       : 2 channels
    Channel positions                : Front: L R
    Sampling rate                    : 44.1 KHz
    Compression mode                 : Lossy
    Stream size                      : 4.38 MiB (98%)
    And ffprobe:-

    Code:
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test3.m4a':
      Metadata:
        major_brand     : M4A 
        minor_version   : 512
        compatible_brands: isomiso2
        creation_time   : 1970-01-01 00:00:00
        encoder         : Lavf52.103.0
        title           : 
        artist          : 
        album           : 
        date            : 
        track           : 0
        genre           : 
        comment         : 
        composer        : 
      Duration: 00:04:01.58, start: 0.000000, bitrate: 154 kb/s
        Stream #0.0(und): Audio: aac, 44100 Hz, stereo, s16, 151 kb/s
        Metadata:
          creation_time   : 1970-01-01 00:00:00

  6. #6
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    Re: Is there a difference between faac and libfaac?

    Hi
    This problem's been fixed in FFmpeg git.
    Information is here:-
    http://git.videolan.org/?p=ffmpeg.gi...46fb7c238e96b2

    Solution is:-
    Compile FFmpeg from git.
    Instructions are here:- http://ubuntuforums.org/showthread.p...ng+FFmpeg+x264

  7. #7
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    Re: Is there a difference between faac and libfaac?

    Good job at bringing this to the attention of FFmpeg and getting it fixed.

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