aacからの変換

■ffmpegのバージョン： Zeranoeビルドの3.3.3

■元ファイル test.aac

■ffmpeg -i test.aac

[aac @ 0000000002892800] Estimating duration from bitrate, this may be inaccurate
Input #0, aac, from 'D:\AAC-Test\test.aac':
  Duration: 00:50:31.29, bitrate: 57 kb/s
    Stream #0:0: Audio: aac (HE-AAC), 48000 Hz, stereo, fltp, 57 kb/s


■ffmpeg -y -loglevel debug -i test.aac -vn -c:a copy test.aac.copy.m4a

ffmpeg version 3.3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 7.1.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
Splitting the commandline.
Reading option '-y' ... matched as option 'y' (overwrite output files) with argument '1'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'debug'.
Reading option '-i' ... matched as input url with argument 'D:\AAC-Test\test.aac'.
Reading option '-vn' ... matched as option 'vn' (disable video) with argument '1'.
Reading option '-c:a' ... matched as option 'c' (codec name) with argument 'copy'.
Reading option 'D:\AAC-Test\test.aac.copy.m4a' ... matched as output url.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option y (overwrite output files) with argument 1.
Applying option loglevel (set logging level) with argument debug.
Successfully parsed a group of options.
Parsing a group of options: input url D:\AAC-Test\test.aac.
Successfully parsed a group of options.
Opening an input file: D:\AAC-Test\test.aac.
[NULL @ 0000000002572ae0] Opening 'D:\AAC-Test\test.aac' for reading
[file @ 0000000002573ee0] Setting default whitelist 'file,crypto'
[aac @ 0000000002572ae0] Format aac probed with size=2048 and score=51
[aac @ 0000000002572ae0] Before avformat_find_stream_info() pos: 0 bytes read:32928 seeks:4 nb_streams:1
[aac @ 0000000002572ae0] All info found
[aac @ 0000000002572ae0] Estimating duration from bitrate, this may be inaccurate
[aac @ 0000000002572ae0] After avformat_find_stream_info() pos: 13312 bytes read:65696 seeks:4 frames:50
Input #0, aac, from 'D:\AAC-Test\test.aac':
  Duration: 00:50:31.29, bitrate: 57 kb/s
    Stream #0:0, 50, 1/28224000: Audio: aac (HE-AAC), 48000 Hz, stereo, fltp, 57 kb/s
Successfully opened the file.
Parsing a group of options: output url D:\AAC-Test\test.aac.copy.m4a.
Applying option vn (disable video) with argument 1.
Applying option c:a (codec name) with argument copy.
Successfully parsed a group of options.
Opening an output file: D:\AAC-Test\test.aac.copy.m4a.
[file @ 0000000002576920] Setting default whitelist 'file,crypto'
Successfully opened the file.
Output #0, ipod, to 'D:\AAC-Test\test.aac.copy.m4a':
  Metadata:
    encoder         : Lavf57.71.100
    Stream #0:0, 0, 1/48000: Audio: aac (HE-AAC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 57 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
cur_dts is invalid (this is harmless if it occurs once at the start per stream)
Automatically inserted bitstream filter 'aac_adtstoasc'; args=''
size=   14653kB time=00:42:51.05 bitrate=  46.7kbits/s speed=5.14e+003x
No more output streams to write to, finishing.
size=   20846kB time=00:59:59.61 bitrate=  47.4kbits/s speed=5.11e+003x
video:0kB audio:21092kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Input file #0 (D:\AAC-Test\test.aac):
  Input stream #0:0 (audio): 84367 packets read (21597928 bytes);
  Total: 84367 packets (21597928 bytes) demuxed
Output file #0 (D:\AAC-Test\test.aac.copy.m4a):
  Output stream #0:0 (audio): 84367 packets muxed (21597928 bytes);
  Total: 84367 packets (21597928 bytes) muxed
0 frames successfully decoded, 0 decoding errors
[AVIOContext @ 00000000025769c0] Statistics: 30 seeks, 84400 writeouts
[AVIOContext @ 000000000257c020] Statistics: 21630856 bytes read, 4 seeks


■ffmpeg -i test.aac.copy.m4a

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\AAC-Test\test.aac.copy.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    encoder         : Lavf57.71.100
  Duration: 00:59:59.66, start: 0.000000, bitrate: 47 kb/s
    Stream #0:0(und): Audio: aac (HE-AAC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 46 kb/s (default)
    Metadata:
      handler_name    : SoundHandler


■ffmpeg -y -loglevel debug -i test.aac -vn -c:a copy test.aac.copy.aac

ffmpeg version 3.3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 7.1.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
Splitting the commandline.
Reading option '-y' ... matched as option 'y' (overwrite output files) with argument '1'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'debug'.
Reading option '-i' ... matched as input url with argument 'D:\AAC-Test\test.aac'.
Reading option '-vn' ... matched as option 'vn' (disable video) with argument '1'.
Reading option '-c:a' ... matched as option 'c' (codec name) with argument 'copy'.
Reading option 'D:\AAC-Test\test.aac.copy.aac' ... matched as output url.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option y (overwrite output files) with argument 1.
Applying option loglevel (set logging level) with argument debug.
Successfully parsed a group of options.
Parsing a group of options: input url D:\AAC-Test\test.aac.
Successfully parsed a group of options.
Opening an input file: D:\AAC-Test\test.aac.
[NULL @ 00000000025a2ae0] Opening 'D:\AAC-Test\test.aac' for reading
[file @ 00000000025a3ee0] Setting default whitelist 'file,crypto'
[aac @ 00000000025a2ae0] Format aac probed with size=2048 and score=51
[aac @ 00000000025a2ae0] Before avformat_find_stream_info() pos: 0 bytes read:32928 seeks:4 nb_streams:1
[aac @ 00000000025a2ae0] All info found
[aac @ 00000000025a2ae0] Estimating duration from bitrate, this may be inaccurate
[aac @ 00000000025a2ae0] After avformat_find_stream_info() pos: 13312 bytes read:65696 seeks:4 frames:50
Input #0, aac, from 'D:\AAC-Test\test.aac':
  Duration: 00:50:31.29, bitrate: 57 kb/s
    Stream #0:0, 50, 1/28224000: Audio: aac (HE-AAC), 48000 Hz, stereo, fltp, 57 kb/s
Successfully opened the file.
Parsing a group of options: output url D:\AAC-Test\test.aac.copy.aac.
Applying option vn (disable video) with argument 1.
Applying option c:a (codec name) with argument copy.
Successfully parsed a group of options.
Opening an output file: D:\AAC-Test\test.aac.copy.aac.
[file @ 00000000025a6920] Setting default whitelist 'file,crypto'
Successfully opened the file.
Output #0, adts, to 'D:\AAC-Test\test.aac.copy.aac':
  Metadata:
    encoder         : Lavf57.71.100
    Stream #0:0, 0, 1/28224000: Audio: aac (HE-AAC), 48000 Hz, stereo, fltp, 57 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
cur_dts is invalid (this is harmless if it occurs once at the start per stream)
size=   15699kB time=00:44:39.29 bitrate=  48.0kbits/s speed=5.35e+003x
No more output streams to write to, finishing.
size=   21092kB time=00:59:59.61 bitrate=  48.0kbits/s speed=5.43e+003x
video:0kB audio:21092kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%
Input file #0 (D:\AAC-Test\test.aac):
  Input stream #0:0 (audio): 84367 packets read (21597928 bytes);
  Total: 84367 packets (21597928 bytes) demuxed
Output file #0 (D:\AAC-Test\test.aac.copy.aac):
  Output stream #0:0 (audio): 84367 packets muxed (21597928 bytes);
  Total: 84367 packets (21597928 bytes) muxed
0 frames successfully decoded, 0 decoding errors
[AVIOContext @ 00000000025a69c0] Statistics: 0 seeks, 84367 writeouts
[AVIOContext @ 00000000025ac020] Statistics: 21630856 bytes read, 4 seeks


■ffmpeg -i test.aac.copy.aac

[aac @ 0000000002842800] Estimating duration from bitrate, this may be inaccurate
Input #0, aac, from 'D:\AAC-Test\test.aac.copy.aac':
  Duration: 00:50:31.29, bitrate: 57 kb/s
    Stream #0:0: Audio: aac (HE-AAC), 48000 Hz, stereo, fltp, 57 kb/s