xref: /third_party/lame/USAGE (revision 159b3361)

% lame [options] inputfile [outputfile]
    inputfile and/or outputfile can be "-", which means stdin/stdout.

For more options, just type:
% lame --help  or lame --longhelp

Note: The HTML documentation is more complete than this text file.


=======================================================================
Constant Bitrate Examples:
=======================================================================
fixed bit rate jstereo 128 kbps encoding:
% lame -b128 sample.wav  sample.mp3

Use highest quality mode, slowest:
% lame -q0 -b128 sample.wav  sample.mp3

Use fast encode, low quality  (no noise shaping)
% lame -f -b128 sample.wav  sample.mp3


=======================================================================
Variable Bitrate Examples:
=======================================================================
LAME has two types of variable bitrate: ABR and VBR.

ABR is the type of variable bitrate encoding usually found in other
MP3 encoders, Vorbis and AAC.  The number of bits is determined by
some metric (like perceptual entropy, or just the number of bits
needed for a certain set of encoding tables), and it is not based on
computing the actual encoding/quantization error.  ABR should always
give results equal or better than CBR:

ABR:   (--abr <x> means encode with an average bitrate of around x kbps)
% lame --abr 128  sample.wav sample.mp3

Another way to enable abr is:
% lame --preset 128 sample.wav sample.mp3


VBR is a true variable bitrate mode which bases the number of bits for
each frame on the measured quantization error relative to the
estimated allowed masking. The value 0 is the highest quality, which
creates bigger files, and the lowest is 9.999, which creates the smallest
files. Decimal values can be specified, like: 4.51.
The resulting filesizes depend on the input material. On typical music 
you can expect -V5 resulting in files averaging 132 kbps, -V2 averaging 
200 kbps.

Variable Bitrate (VBR): (use -V n to adjust quality/filesize)
% lame -V2 sample.wav sample.mp3


=======================================================================
Low Bitrates
=======================================================================
At lower bitrates, (like 24 kbps per channel), it is recommended that
you use a 16 kHz sampling rate combined with lowpass filtering.  LAME,
as well as commercial encoders (FhG, Xing) will do this automatically.
However, if you feel there is too much (or not enough) lowpass
filtering, you may need to try different values of the lowpass cutoff
and passband width (--resample, --lowpass and --lowpass-width options).


=======================================================================
Streaming Example
=======================================================================

% cat inputfile | lame [options] - - > output


=======================================================================
Scripts are included (in the 'misc' subdirectory)
to run lame on multiple files:

bash script:  mlame      Run "mlame -?" for instructions.
sh script:    auenc      Run auenc for instructions
sh script:    mugeco.sh

Perl script which will re-encode mp3 files and preserve id3 tags:
lameid3.pl

Windows scripts:
lame4dos.bat
Lame.vbs   (and an HTML frontend: LameGUI.html)


=======================================================================
options guide:
=======================================================================
These options are explained in detail below.

By default, LAME accepts a PCM audio sample inside a .WAV container as the
input file, in 8, 16, 24 and 32 bits integer and in IEEE FLOAT.
If it is compiled with libsndfile, then it also supports the extra formats
that the library supports.
There is also support for raw PCM data and piped input


Input options:
--scale <arg>   multiply PCM input by <arg>
--scale-l <arg> scale channel 0 (left) input (multiply PCM data) by <arg>
--scale-r <arg> scale channel 1 (right) input (multiply PCM data) by <arg>
--gain number   apply Gain adjustment in decibels, range -20.0 to +12.0.
--swap-channel	Swap Left and Right input channels
--mp1input      input file is an MPEG 1 Layer I file.  decode on the fly
--mp2input      input file is an MPEG 1 Layer II file.  decode on the fly
--mp3input      input file is an MPEG 1 Layer III file.  decode on the fly
--nogap <file1> <file2> <...>
                gapless encoding for a set of contiguous files
--nogapout <dir>
                output dir for gapless encoding (must precede --nogap)
--nogaptags     allow the use of VBR tags in gapless encoding
--out-dir path	If no explicit output file is specified, a file will be
                written at given path. Ignored when using piped/streamed input


Input options for raw PCM:
-r              read the input file as a raw (headerless) PCM stream
-s  n           input sampling frequency in kHz (Default 44.1Khz)
--signed        input is signed (default)
--unsigned      input is unsigned
--bitwidth w    input bit width is w (default 16)
-x              swap bytes of input file
--little-endian input is little-endian (default)
--big-endian    input is big-endian
-a              downmix stereo file to mono file for mono encoding.
                Needed with raw input for the -mm mode to do the downmix.

Resampling and filtering:
--lowpass      Frequency(kHz), lowpass filter cutoff above freq.
               Range [0.001..50]kHz or [50..50000]Hz
--lowpass-width
               Frequency(kHz), lowpass window width.
			   Range [0.001..16]kHz or [16..50000]Hz
			   (See further restriction in the detailed explanation)
--highpass     Frequency(kHz), highpass filter cutoff below freq.
               Range [0.001..16]kHz or [16..50000]Hz
               (See further restriction in the detailed explanation)
--highpass-width
               Frequency(kHz), highpass window width
               (See further restriction in the detailed explanation)
--resample n   Sampling frequency of output file(kHz)
               Default=automatic depending on settings like bitrate.
	
Operational:
--preset type	Enables some preconfigured settings. Check below for each
                of the valid values
--decode        assume input file is an mp3 file, and decode to wav.
--decode-mp3delay samples
                Set the encoder delay to use to decode the input .mp3 file
-t              disable writing of WAV header when using --decode
                (decode to raw pcm, native endian format (use -x to swap))

-m m/s/j/f/a   mode selection
-q n           Internal algorithm quality setting 0..9.
               0 = slowest algorithms, but potentially highest quality
               9 = faster algorithms, very poor quality
			   Default is 3. Read the differences between VBR and CBR below.
-h             same as -q2
-f             same as -q7

--priority <type>
               sets the process priority (Windows and OS/2-specific):
                     0,1 = Low priority (IDLE_PRIORITY_CLASS)
                     2 = normal priority (NORMAL_PRIORITY_CLASS, defaul
                     3,4 = High priority (HIGH_PRIORITY_CLASS))
               Note: Calling '--priority' without a parameter will set it to 0.



Constant Bit Rate (CBR)
-b  n          set bitrate (8, 16, 24, ..., 320)
--freeformat   produce a free format bitstream.  User must also specify
               a bitrate with -b, between 8 and 640 kbps.

Variable Bit Rate (VBR)
-v             VBR  ( alias of -V 4 )
--vbr-old      use old variable bitrate (VBR) routine
--vbr-new      use new variable bitrate (VBR) routine (default)
-V n           VBR quality setting  (0=highest quality, 9.999=lowest)
-b  n          specify a minimum allowed bitrate (8,16,24,...,320)
-B  n          specify a maximum allowed bitrate (8,16,24,...,320)
-F             strictly enforce minimum bitrate
-t             disable VBR informational tag
--nohist       disable display of VBR bitrate histogram

--abr n        specify average bitrate desired



MP3 header/stream options:
-e  n/5/c       de-emphasis
-p              add CRC error protection
-c              mark the encoded file as copyrighted
-o              mark the encoded file as a copy
-S              don't print progress report, VBR histogram
--strictly-enforce-ISO   comply as much as possible to ISO MPEG spec
--replaygain-fast   compute RG fast but slightly inaccurately (default)
--replaygain-accurate   compute RG more accurately and find the peak sample
--noreplaygain  disable ReplayGain analysis
--clipdetect    enable --replaygain-accurate and print a message whether
                clipping occurs and how far the waveform is from full scale


ID3 tagging:

--tt <title>    audio/song title (max 30 chars for version 1 tag)
--ta <artist>   audio/song artist (max 30 chars for version 1 tag)
--tl <album>    audio/song album (max 30 chars for version 1 tag)
--ty <year>     audio/song year of issue (1 to 9999)
--tc <comment>  user-defined text (max 30 chars for v1 tag, 28 for v1.1)
--tn <track[/total]>
                audio/song track number (1 to 255, creates v1.1 tag.
                adding a total force a version 2 tag)
--tg <genre>    audio/song genre (name or number in list)
--ti <file>     audio/song albumArt (jpeg/png/gif file, v2.3 tag)
--tv <id=value> user-defined frame specified by id and value (v2.3 tag)
--add-id3v2     force addition of version 2 tag
--id3v1-only    add only a version 1 tag
--id3v2-only    add only a version 2 tag
--id3v2-utf16   add following options in unicode text encoding
--id3v2-latin1  add following options in latin-1 text encoding
--space-id3v1   pad version 1 tag with spaces instead of nulls
--pad-id3v2     same as '--pad-id3v2-size 128'
--pad-id3v2-size <num>
                adds version 2 tag, pad with extra <num> bytes
--genre-list    print alphabetically sorted ID3 genre list and exit
--ignore-tag-errors
                ignore errors in values passed for tags

Note: A version 2 tag will NOT be added unless one of the input fields
won't fit in a version 1 tag (e.g. the title string is longer than 30
characters), or the '--add-id3v2' or '--id3v2-only' options are used,
or output is redirected to stdout.


Verbosity:
--disptime     secs	Print progress report every secs seconds
--nohist	   Disable VBR histogram display
--silent       Don't print anything on screen
--quiet        Don't print anything on screen
--verbose	   Print a lot of useful information
--version      Print License information
--license	   Print License information
--help         Shows the common list of switches.
               Add id3 or dev to get help for a specified topic
--usage        Shows the common list of switches.
               Add id3 or dev to get help for a specified topic
--longhelp     Shows the complete list of switches



=======================================================================
Detailed description of all options in alphabetical order
=======================================================================


=======================================================================
Downmix
=======================================================================
-a

mix the stereo input file to mono and encode as mono.

This option is only needed in the case of raw PCM stereo input
(because LAME cannot determine the number of channels in the input file).
To encode a stereo (RAW) PCM input file as mono, use "lame -m m -a"

For WAV and AIFF input files, using "-m m" will always produce a
mono .mp3 file from both mono and stereo input.


=======================================================================
Average bitrate encoding (aka Safe VBR)
=======================================================================
--abr n

turns on encoding with a targeted average bitrate of n kbps, allowing
to use frames of different sizes.  The allowed range of n is 8...320
kbps, you can use any integer value within that range.


=======================================================================
Use version 2 of the ID3 tag standard
=======================================================================
 --add-id3v2 Force addition of version 2 tag

Tells LAME to add the tag information as id3v2. This implies adding both,
a version 1 and a version 2 tag, if the values fit on a version 1 tag.
See --id3v1-only and --id3v2-only if you want a more fine-grained control.


=======================================================================
Bitrate
=======================================================================
-b  n

MPEG-1   layer III sample frequencies (kHz):  32  48  44.1
bitrates (kbps): 32 40 48 56 64 80 96 112 128 160 192 224 256 320

MPEG-2   layer III sample frequencies (kHz):  16  24  22.05
bitrates (kbps):  8 16 24 32 40 48 56 64 80 96 112 128 144 160

MPEG-2.5 layer III sample frequencies (kHz):   8  12  11.025
bitrates (kbps):  8 16 24 32 40 48 56 64

The bitrate to be used.  Default is 128kbps in MPEG1 (64 for mono),
64kbps in MPEG2 (32 for mono) and 32kbps in MPEG2.5 (16 for mono).

When used with variable bitrate encodings (VBR), -b specifies the
minimum bitrate to use.  This is useful only if you need to circumvent
a buggy hardware device with strange bitrate constrains.


=======================================================================
Max bitrate
=======================================================================
-B  n

see also option "-b" for allowed bitrates.

Maximum allowed bitrate when using VBR/ABR.

Using -B is NOT RECOMMENDED.  A 128 kbps CBR bitstream, because of the
bit reservoir, can actually have frames which use as many bits as a
320 kbps frame.  ABR/VBR modes minimize the use of the bit reservoir, and
thus need to allow 320 kbps frames to get the same flexability as CBR
streams.  This is useful only if you need to circumvent a buggy hardware
device with strange bitrate constrains.


=======================================================================
Endianess, big.
=======================================================================
 --big-endian Set the byte order to big-endian.

This switch tells LAME that the RAW pcm input is encoded in big-endian
instead of little-endian.


=======================================================================
Sample bit with
=======================================================================
--bitwidth Sets the bitwidth value

With RAW pcm input, this switch lets you specify the bitwidth of the same
(8 bits, 16 bits...)


=======================================================================
Copyright
=======================================================================
-c

flag the encoded file as copyrighted


=======================================================================
Clipping detection
=======================================================================
--clipdetect

Enable --replaygain-accurate and print a message whether clipping
occurs and how far in dB the waveform is from full scale.

This option is not usable if the MP3 decoder was _explicitly_ disabled
in the build of LAME.

See also: --replaygain-accurate


=======================================================================
MPEG audio decode capability
=======================================================================
--decode

This uses LAME's HIP decoder to decode an MP3 file (layers 1, 2 and 3) to
a wav file.

If -t is used (disable wav header), LAME will output
raw pcm in native endian format (use -x to swap bytes).

This option is not usable if the MP3 decoder was _explicitly_ disabled
in the build of LAME.

HIP stands for Hip Isn't a Player and is based off of Michael Hipp's mpglib 0.2a


=======================================================================
MPEG audio decode capability
=======================================================================
--decode-mp3delay x Indicate a different encoder delay for decoding

When decoding an mp3 file, LAME automatically corrects for the start delay
that the encoder had to put into it. This setting lets you specify a different
delay than LAME's own one, so that it is possible to compensate for the delay
of mp3's generated with other encoders.


=======================================================================
De-emphasis
=======================================================================
-e  n/5/c

  n = (none, default)
  5 = 0/15 microseconds
  c = CCITT j.17

All this does is set a flag in the bitstream.  If you have a PCM
input file where one of the above types of (obsolete) emphasis has
been applied, you can set this flag in LAME.  Then the mp3 decoder
should de-emphasize the output during playback, although most
decoders ignore this flag.

A better solution would be to apply the de-emphasis with a standalone
utility before encoding, and then encode without -e.


=======================================================================
Strictly enforce VBR minimum bitrate
=======================================================================
-F

strictly enforce VBR minimum bitrate.   Without this option, passages of
analog silence will be encoded at the minimum bitrate possible (32 or 8,
depending on MPEG version).


=======================================================================
Free format bitstreams
=======================================================================
--freeformat

LAME will produce a fixed bitrate, free format bitstream. User must 
specify the desired bitrate in kbps, which can be any integer between 
8 and 640.

Not supported by most decoders.  Complient decoders (of which there
are few) are only required to support up to 320 kbps.

Decoders known to handle free format:

                      supports up to
mpg123                   640 kbps
MAD                      640 kbps
"lame --decode"          640 kbps
l3dec                    310 kbps


=======================================================================
Gain
=======================================================================
--gain Apply gain in decibels.

Apply Gain adjustment in decibels, range -20.0 to +12.0. 0dBFS means no 
amplification.


=======================================================================
High pass filter
=======================================================================
--highpass number Use a highpass filter when encoding

Enables a highpass filter of the specified frequency when encoding the source.
    Range [0.001..50]kHz or [50..50000]Hz.
This is usually not required, and the gains are usually minimal. May be useful
to remove an interference signal on 50Hz or 60Hz, or a DC offset.
(default: disabled)
Note: The current implementation has a minimum highpass frequency of
(67.5/62)% of the sample rate (I.e. 481Hz at 44Khz).


=======================================================================
High pass filter
=======================================================================
--highpass-width width Set the width of the decaying curve.

Specify the width in Hz of the decaying curve of the highpass.
    Range [16..50000]Hz
The minimum (and default) width is 75% of a band's width (which is 1/64th of
 the sample rate).
Note: See the remark in the --highpass command above.


=======================================================================
ID3 tag modes
=======================================================================
--id3v1-only Disable the use of id3v2.

Put it before any tag setting.
This setting tells LAME to use ID3 v1 tag only, and not create an ID3v2
even if it thinks it should.

--id3v2-only Disable the user ov id3v1.

Put it before any tag setting.
This setting tells LAME to use ID3 v2 tag only. An ID3 v1 tag would not
be written.

--ignore-tag-errors Ignore tag information errors

Put it before any tag setting.
This tells lame to ignore the tag information it sees as erroneous and 
continue encoding without those. Without this setting, errors are reported
and encoding does not start.


=======================================================================
Endianess. little
=======================================================================
--little-endian Set the byte order to little-endian.

This switch tells LAME that the RAW pcm input is encoded in little-endian.
It is the default setting.


=======================================================================
Low pass filter
=======================================================================
--lowpass number Use a lowpass filter when encoding

Enables a lowpass filter of the specified frequency when encoding the source.
    Range [0.001..50]kHz or [50..50000]Hz

Using a lowpass filter helps reducing the amount of data to encode. This is
important in MP3 due to a limitation in very high frequencies (>16Khz).
The default value depends on the target bitrate/quality. It is not recommended
to change it as a general basis.

--lowpass-width width Set the width of the decaying curve.

Specify the width in Hz of the decaying curve of the lowpass.
    Range [0.001..16]kHz or [16..50000]Hz
The lowpass is in the center of this curve. The minimum (and default) width
is 75% of a band's width (which is 1/64th of the sample rate).


=======================================================================
Modes:
=======================================================================
-m m        mono
-m l	    get only the left channel of a stereo signal for a mono output
-m r	    get only the right channel of a stereo signal for a mono output
-m s        (forced) L/R stereo
-m j        joint stereo
-m f        forced mid/side stereo
-m d        dual (independent) channels. Its purpose was meant for dual language
            streams where only one of them should be decoded.
			Most decoders just decode them as a stereo stream.
-m a        Currently, a synonym of m j. (In older releases it selected
            different modes depending on the bitrate)

MONO is the default mode for mono input files.  If "-m m" is specified
for a stereo input file, the two channels will be averaged into a mono
signal.  (Note: See comments about the -a switch for RAW PCM streams)

(FORCED) L/R STEREO encodes the left and the right signals independently,
and gives more or less bits to each, depending on the currently available.

JOINT STEREO is the default mode of encoding.
jstereo means the encoder can use (on a frame by frame basis) either
L/R stereo or mid/side stereo.  In mid/side stereo, the mid(L+R) and side(L-R)
channels are encoded, and more bits are allocated to the mid channel
than the side channel.  When there isn't too much stereo separation, this
effectively increases the bandwidth, so having higher quality with the same
amount of bits.

Using mid/side stereo inappropriately can result in audible
compression artifacts.  Too much switching between mid/side and L/R
stereo can also sound bad. To determine when to switch to mid/side
stereo, LAME uses a much more sophisticated algorithm than that
described in the ISO documentation.

FORCED MID/SIDE STEREO forces all frames to be encoded mid/side stereo.  It
should only be used if you are sure every frame of the input file
has very little stereo seperation.

DUAL CHANNEL mode is similar to encode the left and right as two mono signals.
Its purpose was meant for Dual language streams where only one of them should
be decoded. Most decoders just decode them as a stereo stream

INTENSITY STEREO
	Not supported.


=======================================================================
MP3 input file
=======================================================================
--mp1input --mp2input --mp3input MPEG layer I, II or III input file

Assume the input file is a MP1/2/3 file.  LAME will decode the input file
before re-encoding it.  Since MP3 is a lossy format, this is not recommended 
in general.  But it is useful for creating low bitrate mp3s from high bitrate 
mp3s.  If the filename ends in ".mp3" LAME will assume it is an MP3.  For 
stdin or MP3 files which dont end in .mp3 you need to use this switch.


=======================================================================
No Gap (continuous audio) encoding of multiple files
=======================================================================
 --nogap file1 file2 [...] Encodes multiple continuous files.

Encodes multiple files (ordered by position) which are meant to be played
gaplessly.

By default, LAME will encode the files with accurate length, but the first
and last frame may contain a few erroneous samples for signals that don't
fade-in/out (as is the case of continuous playback).

This setting solves that by using the samples from the next/previous file to
compute the encoding.

--nogapout dir Specify a directory for the output of the files encoded
               with --nogap

This setting should precede --nogap, and is used to specify the alternate
directory where to store the encoded files. The default one is the input file
directory.

--nogaptags Enables the use of VBR tags with files encoded with --nogap

Tells LAME to put VBR tags to encoded files if they are encoded in VBR or ABR
modes. Else, using the --nogap option doesn't generate it.


=======================================================================
Disable historgram display
=======================================================================
--nohist

By default, LAME will display a bitrate histogram while producing
VBR mp3 files.  This will disable that feature.


=======================================================================
Disable ReplayGain analysis
=======================================================================
--noreplaygain

By default ReplayGain analysis is enabled. This switch disables it.

See also: --replaygain-accurate, --replaygain-fast


=======================================================================
Non-original
=======================================================================
-o

mark the encoded file as a copy


=======================================================================
CRC error protection
=======================================================================
-p

Turn on CRC error protection.
It will add a cyclic redundancy check (CRC) code in each frame, allowing
to detect transmission errors that could occur on the MP3 stream. However,
it takes 16 bits per frame that would otherwise be used for encoding, and
therefore will slightly reduce the sound quality.


=======================================================================
ID3 V2 padding
=======================================================================
 --pad-id3v2 Pad ID3v2 tag.

Pads the ID3v2 tag with extra 128bytes to allow it to expand.


=======================================================================
Preset system.
=======================================================================
--preset x Enable one of the presets

   Setting         Meaning
--preset medium	   -V 5
--preset standard  -V 2
--preset extreme   -V 0
--preset insane    -b 320
--preset fast xxx  In versions older than LAME 3.98, "fast" was needed to
                   enable the vbr-new routine. It is no longer needed.
--preset number	   --abr number
--preset cbr number	-b number

Old compatibility settings. Meaningless
--preset phone	   -b 16 -m m
--preset phon+ /
      lw / mw-eu   -b 24 -m m
--preset mw-us     -b 40 -m m
--preset voice     -b 56 -m m
--preset fm / radio -b 112
--preset hifi      -b 160
--preset cd        -b 192
--preset studio    -b 256


=======================================================================
Windows and OS/2 process priority control
=======================================================================
--priority <type>

(Windows and OS/2 only)

Sets the process priority for LAME while running under Windows or IBM OS/2.
This can be very useful to avoid the system becoming slow and/or unresponsive. 
By setting LAME to run in a lower priority, you leave more time for the system 
to update basic processing (drawing windows, polling keyboard/mouse, etc). The 
impact in LAME's performance is minimal if you use priority 0 to 2.

The valid parameters are:

     0 = Low priority (IDLE, delta = 0)
     1 = Medium priority (IDLE, delta = +31)
     2 = Regular priority (REGULAR, delta = -31)
     3 = High priority (REGULAR, delta = 0)
     4 = Maximum priority (REGULAR, delta = +31)

Note that if you call '--priority' without a parameter, priority 0 will be 
assumed.


=======================================================================
Algorithm quality selection
=======================================================================
-q n

Bitrate is of course the main influence on quality. The higher the bitrate,
the higher the quality. But for a given bitrate, we have a choice of algorithms
to determine the best scalefactors and Huffman coding (noise shaping).

For CBR, ABR and --vbr-old modes, the following table applies

-q 0            Use the best algorithms (Best Huffman coding search, full outer
                loop, and the highest precision of several parameters).
-q 1 to -q 4    Similar to -q 0 without the full outer loop and decreasing
                precision of parameters the further from q0. -q 3 is the default
-q 5 and -q 6   Same as -q 7, but enables noise shaping and increases subblock
                gain
-q 7 to -q 9    Same as -f. Very fast, OK quality. Psychoacoustics are used for
                pre-echo and mid/side stereo, but no noise-shaping is done.

For the default VBR mode since LAME 3.98, the following table applies

-q 0 to -q 4    include all features of the other modes and additionally use
                the best search when applying Huffman coding.
-q 5 and -q 6   include all features of -q7, calculate and consider actual
                quantisation noise, and additionally enable subblock gain.
-q 7 to -q 9    This level uses a psymodel but does not calculate quantisation
                noise when encoding: it takes a quick guess.


=======================================================================
Input file is raw pcm
=======================================================================
-r

Assume the input file is raw pcm.  Sampling rate and mono/stereo/jstereo
must be specified on the command line.  Without -r, LAME will perform
several fseek()'s on the input file looking for WAV and AIFF headers.

Not supported if LAME is compiled to use LIBSNDFILE.


=======================================================================
Slightly more accurate ReplayGain analysis and finding the peak sample
=======================================================================
--replaygain-accurate

Compute "Radio" ReplayGain on the decoded data stream. Find the peak sample
by decoding on the fly the encoded data stream and store it in the file.


ReplayGain analysis does _not_ affect the content of a compressed data
stream itself, it is a value stored in the header of a sound file.
Information on the purpose of ReplayGain and the algorithms used is
available from http://www.replaygain.org/

By default, LAME performs ReplayGain analysis on the input data (after
the user-specified volume scaling). This behaviour might give slightly
inaccurate results because the data on the output of a lossy
compression/decompression sequence differs from the initial input data.
When --replaygain-accurate is specified the mp3 stream gets decoded on
the fly and the analysis is performed on the decoded data stream.
Although theoretically this method gives more accurate results, it has
several disadvantages:
  * tests have shown that the difference between the ReplayGain values
    computed on the input data and decoded data is usually no greater
    than 0.5dB, although the minimum volume difference the human ear
    can perceive is about 1.0dB
  * decoding on the fly significantly slows down the encoding process
The apparent advantage is that:
  * with --replaygain-accurate the peak sample is determined and
    stored in the file. The knowledge of the peak sample can be useful
    to decoders (players) to prevent a negative effect called 'clipping'
    that introduces distortion into sound.


Only the "Radio" ReplayGain value is computed. It is stored in the LAME tag.
The analysis is performed with the reference volume equal to 89dB.
Note: the reference volume has been changed from 83dB on transition from 
version 3.95 to 3.95.1.

This option is not usable if the MP3 decoder was _explicitly_ disabled
in the build of LAME. (Note: if LAME is compiled without the MP3 decoder,
ReplayGain analysis is performed on the input data after user-specified
volume scaling).

See also: --replaygain-fast, --noreplaygain, --clipdetect


=======================================================================
Fast ReplayGain analysis
=======================================================================
--replaygain-fast

Compute "Radio" ReplayGain of the input data stream after user-specified
volume scaling and/or resampling.

ReplayGain analysis does _not_ affect the content of a compressed data
stream itself, it is a value stored in the header of a sound file.
Information on the purpose of ReplayGain and the algorithms used is
available from http://www.replaygain.org/

Only the "Radio" ReplayGain value is computed. It is stored in the LAME tag.
The analysis is performed with the reference volume equal to 89dB.
Note: the reference volume has been changed from 83dB on transition
from version 3.95 to 3.95.1.

This switch is enabled by default.

See also: --replaygain-accurate, --noreplaygain


=======================================================================
Output sampling frequency in kHz
=======================================================================
--resample  n

where n = 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48. The values as Hz
instead of Khz are also supported. Else, the value will be ignored.

Output sampling frequency.  Resample the input if necessary.

If not specified, LAME may sometimes resample automatically
when faced with extreme compression conditions (like encoding
a 44.1 kHz input file at 32 kbps).  To disable this automatic
resampling, you have to use --resamle to set the output samplerate
equal to the input samplerate.  In that case, LAME will not
perform any extra computations.


=======================================================================
Sampling frequency in kHz (for input RAW PCM)
=======================================================================
-s  n

where n = sampling rate in kHz.

Required for raw PCM input files.  Otherwise it will be determined
from the header information in the input file.

LAME will automatically resample the input file to one of the
supported MP3 samplerates if necessary.


=======================================================================
Silent operation
=======================================================================
-S

don't print progress report


=======================================================================
Scale
=======================================================================
--scale <arg>

Scales input by <arg>.  This just multiplies the PCM data
(after it has been converted to floating point) by <arg>.

<arg> > 1:  increase volume
<arg> = 1:  no effect
<arg> < 1:  reduce volume

Use with care, since most MP3 decoders will truncate data
which decodes to values greater than 32768.


=======================================================================
Strict ISO complience
=======================================================================
--strictly-enforce-ISO

With this option, LAME will enforce the 7680 bit limitation on
total frame size.  This results in many wasted bits for
high bitrate encodings.


=======================================================================
Disable VBR tag/WAV header
=======================================================================
-t
This setting has two different uses:

When encoding to VBR, this setting disables writing the VBR Tag (also
known as XING tag). This tag is embedded by default in the frame 0 of
MP3 file. It allows VBR aware players to accurately seek and compute playing
times in such files.

When decoding MP3 to WAV using --decode, this flag will disable writing the
WAV header. The output will be raw pcm, native endian format. Use -x to swap
bytes.


=======================================================================
VBR quality setting
=======================================================================
 -V n Enable VBR encoding

Encodes using the VBR algorithm, at the indicated quality.
0=highest quality, bigger files. 9.999=lowest quality, smaller files.
Decimal values can be specified, like: 4.51

On average, the resulting bitrates are as follows:
Setting       Average bitrate (kbps)
    0             245
    2             190
    3             175
    4             165
    5             130

Using -V 7 or higher (lower quality) is not recommended.
ABR usually produces better results.


=======================================================================
Swap bytes
=======================================================================
-x

swap bytes in the input file (and output file when using --decode).
For sorting out little endian/big endian type problems.  If your encodings 
sound like static, try this first.


=======================================================================
Ignore scalefactor band 21
=======================================================================
-Y Ignore noise in sbf21, like CBR mode does

Allows -V2, -V1 and -V0 to not encode the highest frequencies accurately,
if doing so causes disproportional increases in bitrate.
This is the same that CBR and ABR modes do.

Due to the design of the MP3 format, to keep precision in the last scalefactor
band, an encoder needs to increase the precision in all the bands (not only in
this one).
The consequence is an increase of bitrate (+60kbps in some cases) compared to
not keeping that precision. Generally, this band should allow for distortions,
so using this switch shouldn't cause harm.