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