README

   1 % FDKAAC(1)
   2 % nu774 <honeycomb77@gmail.com>
   3 % November, 2013
   4
   5 NAME
   6 ====
   7
   8 fdkaac - command line frontend for libfdk-aac encoder
   9
  10 SYNOPSIS
  11 ========
  12
  13 **fdkaac** [OPTIONS] [FILE]
  14
  15 DESCRIPTION
  16 ===========
  17
  18 **fdkaac** reads linear PCM audio in either WAV, raw PCM, or CAF format,
  19 and encodes it into either M4A / AAC file.
  20
  21 If the input file is "-", data is read from stdin. Likewise, if the
  22 output file is "-", data is written to stdout if one of streamable AAC
  23 transport formats are selected by **-f**.
  24
  25 When CAF input and M4A output is used, tags in CAF file are copied into
  26 the resulting M4A.
  27
  28 OPTIONS
  29 =======
  30
  31 -h, --help
  32 :   Show command help
  33
  34 -o \<FILE\>
  35 :   Output filename.
  36
  37 -p, --profile \<n\>
  38 :   Target profile (MPEG4 audio object type, AOT)
  39
  40     2
  41     :   MPEG-4 AAC LC (default)
  42
  43     5
  44     :   MPEG-4 HE-AAC (SBR)
  45
  46     29
  47     :   MPEG-4 HE-AAC v2 (SBR+PS)
  48
  49     23
  50     :   MPEG-4 AAC LD
  51
  52     39
  53     :   MPEG-4 AAC ELD
  54
  55     129
  56     :   MPEG-2 AAC LC
  57
  58     132
  59     :   MPEG-2 HE-AAC (SBR)
  60
  61     156
  62     :   MPEG-2 HE-AAC v2 (SBR+PS)
  63
  64 -b, --bitrate \<n\>
  65 :   Target bitrate (for CBR)
  66
  67 -m, --bitrate-mode \<n\>
  68 :   Bitrate configuration mode. Available VBR quality value depends on
  69     other parameters such as profile, sample rate, or number of
  70     channels.
  71
  72     0
  73     :   CBR (default)
  74
  75     1-5
  76     :   VBR (higher value -\> higher bitrate)
  77
  78 -w, --bandwidth \<n\>
  79 :   Frequency bandwidth (lowpass cut-off frequency) in Hz. Available on
  80     AAC LC only.
  81
  82 -a, --afterburner \<n\>
  83 :   Configure afterburner mode. When enabled, quality is increased at
  84     the expense of additional computational workload.
  85
  86     0
  87     :   Off
  88
  89     1
  90     :   On (default)
  91
  92 -L, --lowdelay-sbr \<n\>
  93 :   Configure SBR activity on AAC ELD.
  94
  95     -1
  96     :   Use ELD SBR auto configuration
  97
  98     0
  99     :   Disable SBR on ELD (default)
 100
 101     1
 102     :   Enable SBR on ELD
 103
 104 -s, --sbr-ratio \<n\>
 105 :   Controls activation of downsampled SBR.
 106
 107     0
 108     :   Use lib default (default)
 109
 110     1
 111     :   Use downsampled SBR (default for ELD+SBR)
 112
 113     2
 114     :   Use dual-rate SBR (default for HE-AAC)
 115
 116     Dual-rate SBR is what is normally used for HE-AAC, where AAC is
 117     encoded at half the sample rate of SBR, hence "dual rate". On the
 118     other hand, downsampled SBR uses same sample rate for both of AAC
 119     and SBR (single rate), therefore downsampled SBR typically consumes
 120     more bitrate.
 121
 122     Downsampled SBR is newly introduced feature in FDK encoder library
 123     version 3.4.12. When libfdk-aac in the system doesn't support this,
 124     dual-rate SBR will be used. When available, dual-rate SBR is the
 125     default for HE-AAC and downsampled SBR is the default for ELD+SBR.
 126
 127     Note that downsampled HE-AAC is not so common as dual-rate one. When
 128     downsampled HE-AAC is selected, **fdkaac** is forced to choose
 129     explicit hierarchical SBR signaling, which (at least) iTunes doesn't
 130     accept.
 131
 132 -f, --transport-format \<n\>
 133 :   Transport format. Tagging and gapless playback is only available on
 134     M4A. Streaming to stdout is only available on others.
 135
 136     0
 137     :   M4A (default)
 138
 139     1
 140     :   ADIF
 141
 142     2
 143     :   ADTS
 144
 145     6
 146     :   LATM MCP=1
 147
 148     7
 149     :   LATM MCP=0
 150
 151     10
 152     :   LOAS/LATM (LATM within LOAS)
 153
 154 -C, --adts-crc-check
 155 :   Add CRC protection on ADTS header.
 156
 157 -h, --header-period \<n\>
 158 :   StreamMuxConfig/PCE repetition period in the transport layer.
 159
 160 -G, --gapless-mode \<n\>
 161 :   Method to declare amount of encoder delay (and padding) in M4A
 162     container. These values are mandatory for proper gapless playback on
 163     player side.
 164
 165     0
 166     :   iTunSMPB (default)
 167
 168     1
 169     :   ISO standard (edts and sgpd)
 170
 171     2
 172     :   Both
 173
 174 --include-sbr-delay
 175 :   When specified, count SBR decoder delay in encoder delay.
 176
 177     This is not iTunes compatible and will lead to gapless playback
 178     issue on LC only decoder, but this is the default behavior of FDK
 179     library.
 180
 181     Whether counting SBR decoder delay in encoder delay or not result in
 182     incompatibility in gapless playback. You should pick which one will
 183     work for your favorite player.
 184
 185     However, it's better not to choose SBR at all if you want gapless
 186     playback. LC doesn't have such issues.
 187
 188 -I, --ignorelength
 189 :   Ignore length field of data chunk in input WAV file.
 190
 191 -S, --silent
 192 :   Don't print progress messages.
 193
 194 --moov-before-mdat
 195 :   Place moov box before mdat box in M4A container. This option might
 196     be important for some hardware players, that are known to refuse
 197     moov box placed after mdat box.
 198
 199 -R, --raw
 200 :   Regard input as raw PCM.
 201
 202 --raw-channels \<n\>
 203 :   Specify number of channels of raw input (default: 2)
 204
 205 --raw-rate \<n\>
 206 :   Specify sample rate of raw input (default: 44100)
 207
 208 --raw-format \<spec\>
 209 :   Specify sample format of raw input (default: "S16L"). **Spec** is as
 210     the following (case insensitive):
 211
 212     1st char -- type of sample
 213     :   **S** (igned) | **U** (nsigned) | **F** (loat)
 214
 215     2nd part (in digits)
 216     :   bits per channel
 217
 218     Last char -- endianness (can be omitted)
 219     :   **L** (ittle, default) | **B** (ig)
 220
 221 --title \<string\>
 222 :   Set title tag.
 223
 224 --artist \<string\>
 225 :   Set artist tag.
 226
 227 --album \<string\>
 228 :   Set album tag.
 229
 230 --genre \<string\>
 231 :   Set genre tag.
 232
 233 --date \<string\>
 234 :   Set date tag.
 235
 236 --composer \<string\>
 237 :   Set composer tag.
 238
 239 --grouping \<string\>
 240 :   Set grouping tag.
 241
 242 --comment \<string\>
 243 :   Set comment tag.
 244
 245 --album-artist \<string\>
 246 :   Set album artist tag.
 247
 248 --track \<number[/total]\>
 249 :   Set track tag, with or without number of total tracks.
 250
 251 --disk \<number[/total]\>
 252 :   Set disk tag, with or without number of total discs.
 253
 254 --tempo \<n\>
 255 :   Set tempo (BPM) tag.
 256
 257 --tag \<fcc\>:\<value\>
 258 :   Set iTunes predefined tag with explicit fourcc key and value. See
 259     [https://code.google.com/p/mp4v2/wiki/iTunesMetadata](https://code.google.com/p/mp4v2/wiki/iTunesMetadata)
 260     for known predefined keys. You can omit first char of **fcc** when
 261     it is the copyright sign.
 262
 263 --tag-from-file \<fcc\>:\<filename\>
 264 :   Same as --tag, but set content of file as tag value.
 265
 266 --long-tag \<name\>:\<value\>
 267 :   Set arbitrary tag as iTunes custom metadata. Stored in
 268     com.apple.iTunes field.
 269
 270 --tag-from-json \<filename[?dot\_notation]\>
 271 :   Read tags from JSON. By default, tags are assumed to be direct
 272     children of the root object in JSON. Optionally you can specify
 273     arbitrary dot notation to locate the object containing tags.
 274
 275
 276 EXAMPLES
 277 ========
 278
 279 Encode WAV file into a M4A file. MPEG4 AAC LC, VBR quality 3:
 280
 281     fdkaac -m3 foo.wav
 282
 283 Encode WAV file into a M4A file. MPEG4 HE-AAC, bitrate 64kbps:
 284
 285     fdkaac -p5 -b64 foo.wav
 286
 287 Piping from **ffmpeg** (you need version supporting CAF output):
 288
 289     ffmpeg -i foo.flac -f caf - | fdkaac -b128 - -o foo.m4a
 290
 291 Import tags via json:
 292
 293     ffprobe -v 0 -of json -show_format foo.flac >foo.json
 294
 295     flac -dc foo.flac | \
 296     fdkaac - -ox.m4a -m2 --import-tag-from-json=foo.json?format.tags
 297
 298 NOTES
 299 =====
 300
 301 Upto 32bit integer or 64bit floating point format is supported as input.
 302 However, FDK library is implemented based on fixed point math and only
 303 supports 16bit integer PCM. Therefore, be wary of clipping. You might
 304 want to dither/noise shape beforehand when your input has higher
 305 resolution.
 306
 307 Following channel layouts are supported by the encoder.
 308
 309 1ch
 310 :   C
 311
 312 2ch
 313 :   L R
 314
 315 3ch
 316 :   C L R
 317
 318 4ch
 319 :   C L R Cs
 320
 321 5ch
 322 :   C L R Ls Rs
 323
 324 5.1ch
 325 :   C L R Ls Rs LFE
 326
 327 7.1ch (front)
 328 :   C Lc Rc L R Ls Rs LFE
 329
 330 7.1ch (rear)
 331 :   C L R Ls Rs Rls Rrs LFE
 332