Encoding Options Help
For the most part, the recommended setting for getting high quality MP3s from LAME is --alt-preset standard, but you can mix and match from a huge number of other options. The encoding options are sent directly to LAME, and can be a little cryptic at first. Essentially, you type as many options as you like, with spaces in between them.
The equivalents for the iTunes MP3 settings are:
Good Quality: -b 128
High Quality: -b 160
Higher Quality: -b 192
For variable bit rate:
Lowest: -v -V 9
Low: -v -V 6
Medium: -v -V 4
High: -v -V 2
Highest: -v -V 0
You can combine the Variable Bit Rate and the Constant Bit Rate (e.g. -b 160) to specify a guaranteed minimum.
Adding a -h improves the quality of the encoding, but makes it take longer.
Putting it all together, if you wanted a well encoded, Medium-quality VBR file with a minimum bit rate of 128, you could use these as your encoding options:
-v -V 4 -b 128 -h
In addition to the standard options, LAME includes a number of presets:
Very High Quality: --alt-preset standard
Even Higher Quality: --alt-preset extreme
Highest Possible Quality: --alt-preset insane
iTunes-LAME implements a few extra options:
--vcomment will add version and encoding options information to empty comments fields.
--multi will run multiple encoders at once, enabled automatically on a dual-processor machine.
--delete-source will delete the source file if it is successfully encoded.The file is immediately removed, so use this with an appropriate amount of caution.
An exhaustive list of the options, pulled straight from LAME, is listed below. Avoid the Verbosity and ID3 tag sections, as display and tagging is all handled automatically.
Good luck, and happy encoding...
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LAME Help
Operational options:
-a downmix from stereo to mono file for mono encoding
-m <mode> (j)oint, (s)imple, (f)orce, (d)dual-mono, (m)ono
default is (j) or (s) depending on bitrate
joint = joins the best possible of MS and LR stereo
simple = force LR stereo on all frames
force = force MS stereo on all frames.
--preset type type must be "medium", "standard", "extreme", "insane",
or a value for an average desired bitrate and depending
on the value specified, appropriate quality settings will
be used.
"--preset help" gives more info on these
--comp <arg> choose bitrate to achive a compression ratio of <arg>
--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
--freeformat produce a free format bitstream
--decode input=mp3 file, output=wav
-t disable writing wav header when using --decode
Verbosity:
--disptime <arg>print progress report every arg seconds
-S don't print progress report, VBR histograms
--nohist disable VBR histogram display
--silent don't print anything on screen
--quiet don't print anything on screen
--brief print more useful information
--verbose print a lot of useful information
Noise shaping & psycho acoustic algorithms:
-q <arg> <arg> = 0...9. Default -q 5
-q 0: Highest quality, very slow
-q 9: Poor quality, but fast
-h Same as -q 2. Recommended.
-f Same as -q 7. Fast, ok quality
CBR (constant bitrate, the default) options:
-b <bitrate> set the bitrate in kbps, default 128 kbps
--cbr enforce use of constant bitrate
ABR options:
--abr <bitrate> specify average bitrate desired (instead of quality)
VBR options:
-v use variable bitrate (VBR) (--vbr-old)
--vbr-old use old variable bitrate (VBR) routine
--vbr-new use new variable bitrate (VBR) routine
-V n quality setting for VBR. default n=4
0=high quality,bigger files. 9=smaller files
-b <bitrate> specify minimum allowed bitrate, default 32 kbps
-B <bitrate> specify maximum allowed bitrate, default 320 kbps
-F strictly enforce the -b option, for use with players that
do not support low bitrate mp3
-t disable writing LAME Tag
-T enable and force writing LAME Tag
PSY related:
--short use short blocks when appropriate
--noshort do not use short blocks
--allshort use only short blocks
--notemp disable temporal masking effect
--nssafejoint M/S switching criterion
--nsmsfix <arg> M/S switching tuning [effective 0-3.5]
--interch x adjust inter-channel masking ratio
--ns-bass x adjust masking for sfbs 0 - 6 (long) 0 - 5 (short)
--ns-alto x adjust masking for sfbs 7 - 13 (long) 6 - 10 (short)
--ns-treble x adjust masking for sfbs 14 - 21 (long) 11 - 12 (short)
--ns-sfb21 x change ns-treble by x dB for sfb21
experimental switches:
-X n[,m] selects between different noise measurements
n for long block, m for short. if m is omitted, m = n
-Y lets LAME ignore noise in sfb21, like in CBR
-Z [n] currently no effects
MP3 header/stream options:
-e <emp> de-emphasis n/5/c (obsolete)
-c mark as copyright
-o mark as non-original
-p error protection. adds 16 bit checksum to every frame
(the checksum is computed correctly)
--nores disable the bit reservoir
--strictly-enforce-ISO comply as much as possible to ISO MPEG spec
Filter options:
-k keep ALL frequencies (disables all filters),
Can cause ringing and twinkling
--lowpass <freq> frequency(kHz), lowpass filter cutoff above freq
--lowpass-width <freq> frequency(kHz) - default 15% of lowpass freq
--highpass <freq> frequency(kHz), highpass filter cutoff below freq
--highpass-width <freq> frequency(kHz) - default 15% of highpass freq
--resample <sfreq> sampling frequency of output file(kHz)- default=automatic
ID3 tag options:
--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 255, 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
--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.
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 80 96 112 128 144 160