TWOLAME(1)
NAME
twolame - an optimised MPEG Audio Layer 2 (MP2) encoder
SYNOPSIS
twolame [options] <infile> [outfile].sp
DESCRIPTION
TwoLAME is an optimised MPEG Audio Layer 2 (MP2) encoder based on
tooLAME by Mike Cheng, which in turn is based upon the ISO dist10 code
and portions of LAME. Encoding is performed by the libtwolame library
backend..sp
OPTIONS
- Input File
- twolame uses libsndfile for reading the input sound file, so the input
file can be in any format supported by libsndfile. To read raw PCM
audio from STDIN, then use - as the input filename..sp - Output File
- If no output filename is specified, then suffix of the input filename
is automatically changed to .mp2. To write the encoded audio to STDOUT then use - as the output filename..sp - Input Options
- -r, --raw-input
Specifies that input is raw signed PCM audio. If audio is stereo,
than audio samples are interleaved between the two channels. - -x, --byte-swap
Force byte-swapping of the input. Endian detection is performed
automatically by libsndfile, so this option shouldn't normally be
needed. - -s, --samplerate <int>
If inputting raw PCM sound, you must specify the sample rate of the audio in Hz. Valid sample rates: 16000, 22050, 24000, 32000, 44100, 48000Hz. Default sample rate is 44100Hz.
- --samplesize <int>
Specifies the sample size (in bits) of the raw PCM audio. Valid
sample sizes: 8, 16, 24, 32. Default sample size is 16-bit. - -N, --channels <int>
If inputting raw PCM sound, you must specify the number of channels in the input audio. Default number of channels is 2.
- -g, --swap-channels
Swap the Left and Right channels of a stereo input file.
- --scale <float>
Scale the input audio prior to encoding. All of the input audio is
multiplied by specified value. Value between 0 and 1 will reduce the audio gain, and a value above 1 will increase the gain of the audio. - --scale-l <float>
Same as --scale, but only affects the left channel.
- --scale-r <float>
Same as --scale, but only affects the right channel.
- Output Options
- -m, --mode <char>
Choose the mode of the resulting audio. Default is auto.
o "a" auto - choose mode automatically based on the inputo "s" stereoo "d" dual channelo "j" joint stereoo "m" mono-a, --downmixIf the input file is stereo then, downmix the left and right input
channels into a single mono channel.-b, --bitrate <int>Sets the total bitrate (in kbps) for the output file. The default
bitrate depends on the number of input channels and samplerate.
------------------------------Sample Rate Mono Stereo
------------------------------48000 96 192
44100 96 192
32000 80 160
24000 48 96
22050 48 96
16000 32 64
-------------------------------P, --psyc-mode <int>Choose the psycho-acoustic model to use (-1 to 4). Model number -1
is turns off psycho-acoustic modelling and uses fixed default values instead. Please see the file psycho for a full description of each of the models available. Default model is 3.-v, --vbrEnable VBR mode. See vbr documentation file for details. Default VBR level is 5.0.-v, --vbr-level <float>Enable VBR mode and set quality level. The higher the number the
better the quality. Maximum range is -50 to 50 but useful range is
-10 to 10. See vbr documentation file for details.-l, --ath <float>Set the ATH level. Default level is 0.0.-q, --quick <int>Enable quick mode. Only re-calculate psycho-acoustic model every
specified number of frames.-S, --single-frameEnables single frame mode: only a single frame of MPEG audio is
output and then the program terminates. - Miscellaneous Options
- -c, --copyright
Turn on Copyright flag in output bitstream.
- -o, --non-original
Turn off Original flag in output bitstream.
- --original
Turn on Original flag in output bitstream.
- -p, --protect
Enable CRC error protection in output bitstream. An extra 16-bit
checksum is added to frames. - -d, --padding
Turn on padding in output bitstream.
- -R, --reserve <int>
Reserve specified number of bits in the each from of the output
bitstream. - -e, --deemphasis <char>
Set the de-emphasis type (n/c/5). Default is none.
- -E, --energy
Turn on energy level extensions.
- Verbosity Options
- -t, --talkativity <int>
Set the amount of information to be displayed on stderr (0 to 10).
Default is 2. - --quiet
Don't send any messages to stderr, unless there is an error. (Same
as --talkativity=0) - --brief
Only display a minimal number of messages while encoding. This
setting is quieter than the default talkativity setting. (Same as
--talkativity=1) - --verbose
Display an increased number of messages on stderr. This setting is
useful to diagnose problems. (Same as --talkativity=4)
RETURN CODES
If encoding completes successfully, then twolame will return 0. However
if encoding is not successful, then it will return one of the following
codes..sp
o 1 (No encoding performed)
o 2 (Error opening input file)
o 4 (Error opening output file)
o 6 (Error allocating memory)
o 8 (Error in chosen encoding parameters)
o 10 (Error reading input audio)
o 12 (Error occured while encoding)
o 14 (Error writing output audio)
EXAMPLES
- This will encode sound.wav to sound.mp2 using the default constant
bitrate of 192 kbps and using the default psycho-acoustic model (model 3):.sp - twolame sound.wav
- Constant bitrate of 160kbps and joint stereo encoding, saved to file
sound_160.mp2:.sp
twolame -b 160 -m j sound.aiff sound_160.mp2- Encode sound.wav to newfile.mp2 using psycho-acoustic model 2 and
encoding with variable bitrate:.sp
twolame -P 2 -v sound.wav newfile.mp2- Same as example above, except that the negative value of the "-V"
argument means that the lower bitrates will be favoured over the higher ones:.sp
twolame -P 2 -V -5 sound.wav newfile.mp2- Resample audio file using sox and pipe straight through twolame:.sp
sox sound_11025.aiff -t raw -r 16000 | twolame -r -s 16000 - - > out.mp2
AUTHORS
The twolame frontend was (re)written by Nicholas J Humfrey. The
libtwolame library is based on toolame by Mike Cheng. For a full list
of authors, please see the AUTHORS file..sp
RESOURCES
TwoLAME web site: http://www.twolame.org/.sp
SEE ALSO
lame(1), mpg123(1), madplay(1), sox(1).sp
COPYING
- Copyright (C) 2004-2006 The TwoLAME Project. Free use of this software
is granted under the terms of the GNU Lesser General Public License
(LGPL)..sp