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Aminet 40 (2000)(Schatztruhe)[!][Dec 2000].iso
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USAGE
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% lame [options] inputfile [outputfile]
=======================================================================
Examples:
=======================================================================
fixed bit rate jstereo 128 kbps encoding:
% lame sample.wav sample.mp3
fixed bit rate jstereo 128 kbps encoding, highest quality: (recommended)
% lame -h sample.wav sample.mp3
To disable joint stereo encoding (slightly faster, but less quality at
bitrates <= 128 kbps)
% lame -m s sample.wav sample.mp3
Fast encode, low quality (no noise shaping)
% lame -f sample.wav sample.mp3
Variable Bitrate (VBR): (use -V n to adjust quality/filesize)
% lame -h -v sample.wav sample.mp3
Note: VBR is currently under heavy development. Right now it can
often result in too much compression. I would recommend using VBR
with a minimum bitrate of 112 kbps. This will let LAME increase
the bitrate for difficult-to-encode frames, but prevent LAME from
being too aggressive for simple frames:
% lame -h -v -b 112 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 EXAMPLES
=======================================================================
% cat inputfile | lame [options] - - > output
=======================================================================
For more options, just type:
% lame --help
Scripts are included to run lame on multiple files:
bach script: mlame Run "mlame -?" for instructions.
sh script: auenc Run auenc for instructions
=======================================================================
options guide:
=======================================================================
These options are explained in detail below.
Quality related:
-m m/s/j/f mode selection
-k disable all filtering
-d allow block types to differ between channels
--athonly ignore psy-model output, only use masking from the ATH
--voice experimental voice encoding mode
--noshort disable short blocks
Constant Bit Rate (CBR)
-b n set bitrate (8, 16, 24, ..., 320)
-h higher quality but slower
-f disable noise shaping. Encodes faster, but lower quality
--freeformat produce a free format bitstream. User must also specify
a bitrate with -b, between 8 and 320 kbps.
Variable Bit Rate (VBR)
-v VBR
--vbr-old use old variable bitrate (VBR) routine (default)
--vbr-new use new variable bitrate (VBR) routine
-V n VBR quality setting (0=highest quality, 9=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 Xing VBR informational tag
--nohist disable display of VBR bitrate histogram
--abr n specify average bitrate desired
Experimental (undocumented): may work better or worse:
-X n try different quality measures (when comparing quantizations)
-Y
-Z
Operational:
-r assume input file is raw PCM
-s n input sampling frequency in kHz (for raw PCM input files)
--resample n output sampling frequency
--mp3input input file is an MP3 file. decode using mpglib/mpg123
--ogginput input file is an Ogg Vorbis file. decode using libvorbis
-x swap bytes of input file
--scale <arg> multiply PCM input by <arg>
-a downmix stereo input file to mono .mp3
-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
-g run MP3x, the graphical frame analyzer
--strictly-enforce-ISO comply as much as possible to ISO MPEG spec
--decode assume input file is an mp3 file, and decode to wav.
-t disable writing of WAV header when using --decode
(decode to raw pcm, native endian format (use -x to swap))
--ogg Encode using Ogg Vorbis (.ogg) instead of mp3.
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> audio/song track number (1 to 99, creates v1.1 tag)
--tg <genre> audio/song genre (name or number in list)
--add-id3v2 force addition of version 2 tag
--id3v1-only add only a version 1 tag
--id3v2-only add only a version 2 tag
--space-id3v1 pad version 1 tag with spaces instead of nulls
--pad-id3v2 pad version 2 tag with extra 128 bytes
--genre-list print alphabetically sorted ID3 genre list and exit
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.
options not yet described:
--nores disable bit reservoir
--noath disable ATH
--athlower <n db> lower the ATH by n db.
--athshort use only the ATH for short blocks
--cwlimit <freq> specify range of tonality calculation
--disptime
--lowpass
--lowpass-width
--highpass
--highpass-width
=======================================================================
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 PCM input file as mono, use "lame -m s -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.
It can be combined with the -b and -B switches like
lame --abr 123 -b 64 -B 192 a.wav a.mp3
which would limit the allowed frame sizes between 64 and 192 kbps.
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. 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.
=======================================================================
ATH only
=======================================================================
--athonly
This option causes LAME to ignore the output of the psy-model and
only use masking from the ATH. Might be useful at very high bitrates
or for testing the ATH.
=======================================================================
bitrate
=======================================================================
-b n
For MPEG-1 (sampling frequencies of 32, 44.1 and 48 kHz)
n = 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320
For MPEG-2 and MPEG-2.5 (sampling frequencies of 8, 11.025,
12, 16, 22.05 and 24 kHz)
n = 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160
The bitrate to be used. Default is 128 kbps MPEG1, 80 kbps MPEG2.
When used with variable bitrate encodings (VBR), -b specifies the
minimum bitrate to use. This is useful to prevent LAME VBR from
using some very aggressive compression which can cause some distortion
due to small flaws in the psycho-acoustic model.
=======================================================================
max bitrate
=======================================================================
-B n
see also option "-b" for allowed bitrates.
Maximum allowed bitrate when using VBR.
=======================================================================
copyright
=======================================================================
-c
mark the encoded file as copyrighted
=======================================================================
block type control
=======================================================================
-d
Allows the left and right channels to use different block types.
Normally this is not allowed, only because the FhG encoder does
not seem to allow it either. If anyone finds a sample where -d
produces better results, let me know. (mt@sulaco.org)
=======================================================================
mpglib decode capability
=======================================================================
--decode
This just uses LAME's mpg123/mpglib interface to decode an MP3 file to
a wav file. The input file can be any input type supported by
encoding, including .mp3 (layers 1, 2 and 3) and .ogg.
If -t is used (disable wav header), LAME will output
raw pcm in native endian format (use -x to swap bytes).
=======================================================================
de-emphasis
=======================================================================
-e n/5/c
n = (none, default)
5 = 0/15 microseconds
c = citt 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.
=======================================================================
fast mode
=======================================================================
-f
disable noise shaping. Encodes faster, but lower quality.
Psycho acoustics are computed for bit allocation and
pre-echo detection.
=======================================================================
strictly enforce VBR minimum bitrate
=======================================================================
-F
strictly enforce VBR minimum bitrate. With out this optioni, the minimum
bitrate will be ignored for passages of analog silence.
=======================================================================
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 320.
Not supported by most decoders. Decoders only required to support
up to 320 kbps.
Decoders which can handle free format:
supports up to
"lame --decode" 550 kbps
Freeamp: 440 kbps
l3dec: 310 kbps
=======================================================================
graphical frame analyzer
=======================================================================
-g
run MP3x, the graphical frame analyzer analysis on the inputfile. The
inputfile can be either an .mp3 file or uncompressed audio file. MP3x
support must be compiled into LAME, and requires GTK 1.2.
Documentation (outdated) is under the About pull down menu.
=======================================================================
high quality
=======================================================================
-h
use (maybe) some quality improvements
LAME 3.21 and up: -h enables specialized mid/side masking thresholds to
be used in jstereo mode. Will sound better in jstereo mode
but is 20% slower. No effect for mono files.
LAME 3.58beta and up: -h also enables a more accurate but slightly
slower quantization formula.
=======================================================================
keep all frequencies
=======================================================================
-k
keep all frequencies. (Disable all filters)
LAME will automatically apply various types of lowpass filters. This
is because the high frequency coefficients can take up a lot of bits
that would be better used for lower, more important frequencies.
-k will disable all lowpass filtering. Not recommended.
=======================================================================
Modes:
=======================================================================
-m m mono
-m s stereo
-m j joint stereo
-m f forced mid/side stereo
-m d dual (independent) channels
-m i intensity stereo
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.
STEREO
JOINT STEREO is the default mode for stereo files with fixed bitrates of
128 kbps or less. At higher fixed bitrates, the default is stereo.
For VBR encoding, jstereo is the default for VBR_q >4, and stereo
is the default for VBR_q <=4. You can override all of these defaults
by specifing the mode on the command line.
jstereo means the encoder can use (on a frame by frame bases) either
regular stereo (just encode left and right channels independently)
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. This will effectively increase the bandwidth
if the signal does not have too much stereo separation.
Mid/side stereo is basically a trick to increase bandwidth. At 128 kbps,
it is clearly worth while. At higher bitrates it is less useful.
Using mid/side stereo inappropriately can result in audible
compression artifacts. To much switching between mid/side and regular
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 CHANNELS
INTENSITY STEREO
=======================================================================
MP3 input file
=======================================================================
--mp3input
Assume the input file is a MP3 file. Usefull for downsampling from
one mp3 to another. 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.
=======================================================================
disable historgram display
=======================================================================
--nohist
By default, LAME will display a bitrate histogram while producing
VBR mp3 files. This will disable that feature.
=======================================================================
disable short blocks
=======================================================================
--noshort
Encode all frames using long blocks.
=======================================================================
non-original
=======================================================================
-o
mark the encoded file as a copy
=======================================================================
Ogg Vorbis encoding
=======================================================================
--ogg
Encode using the Ogg Vobis codec (using libvorbis) instead of
LAME's internal mp3 codec.
Most options related to the internal workings of the MP3 format
are ignored when using "--ogg". But downsampling and stereo/mono
options work.
Currently (8/00) Ogg Vorbis only supports 5 modes, which range
from approximately 128 kbps to 320 kbps. Based on the bitrate
specified (or the -V n option), LAME will take its best guess
as to which of the 5 Vorbis modes will give about close to the
desired bitrate.
=======================================================================
Ogg Vorbis input file
=======================================================================
--ogginput
Assume the input file is an Ogg Vorbis file. Mostly usefull
with --decode for playing back .ogg files, or converting
your .ogg collection to MP3 :-)
If the filename ends in ".ogg" LAME will assume it is Ogg. For
stdin or files which dont end in .ogg you need to use this switch.
=======================================================================
CRC error protection
=======================================================================
-p
turn on CRC error protection.
Yes this really does work correctly in LAME. However, it takes
16 bits per frame that would otherwise be used for encoding.
=======================================================================
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.
=======================================================================
output sampling frequency in kHz
=======================================================================
--resample n
where n = 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48
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).
=======================================================================
sampling frequency in kHz
=======================================================================
-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 Xing VBR tag
=======================================================================
-t
Disable writing of the Xing VBR Tag (only valid if -v flag is
specified) This tag in embedded in frame 0 of the MP3 file. It lets
VBR aware players correctly seek and compute playing times of VBR
files.
When '--decode' is specified (decode mp3 to wav), this flag will
disable writing the WAV header. The output will be raw pcm,
native endian format. Use -x to swap bytes.
=======================================================================
variable bit rate (VBR)
=======================================================================
-v
Turn on VBR. There are several ways you can use VBR. I personally
like using VBR to get files slightly bigger than 128 kbps files, where
the extra bits are used for the occasional difficult-to-encode frame.
For this, try specifying a minimum bitrate to use with VBR:
lame -v -b 112 input.wav output.mp3
If the file is too big, use -V n, where n = 0...9
lame -v -V n -b 112 input.wav output.mp3
If you want to use VBR to get the maximum compression possible,
and for this, you can try:
lame -v input.wav output.mp3
lame -v -V n input.wav output.mp3 (to vary quality/filesize)
=======================================================================
VBR quality setting
=======================================================================
-V n
n = 0...9. Specifies the value of VBR_q.
default = 4, highest quality = 0, smallest files = 9
How is VBR_q used?
The value of VBR_q influences two basic parameters of LAME's psycho
acoustics:
a) the absolute threshold of hearing
b) the sample to noise ratio
The lower the VBR_q value the lower the injected quantization noise
will be.
*NOTE* No psy-model is perfect, so there can often be distortion which
is audible even though the psy-model claims it is not! Thus using a
small minimum bitrate can result in some aggressive compression and
audible distortion even with -V 0. Thus using -V 0 does not sound
better than a fixed 256 kbps encoding. For example: suppose in the 1 kHz
frequency band the psy-model claims 20 dB of distortion will not be
detectable by the human ear, so LAME VBR-0 will compress that
frequency band as much as possible and introduce at most 20 dB of
distortion. Using a fixed 256 kbps framesize, LAME could end up
introducing only 2 dB of distortion. If the psy-model was correct,
they will both sound the same. If the psy-model was wrong, the VBR-0
result can sound worse.
=======================================================================
voice encoding mode
=======================================================================
--voice
An experimental voice encoding mode. Tuned for 44.1 kHz input files.
=======================================================================
swapbytes
=======================================================================
-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.