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.TH MP3ENC 1

.SH NAME

mp3enc \- create mp3 audio files

.SH SYNOPSIS

.in +0.5i

.ti -0.5i

.B games/mp3enc

[

.B -hprv

] [

.B -b

.I bitrate

] [

.B -B

.I bitrate

] [

.B -m

.I mode

] [

.B -q

q ] [

.B -s

.I sfreq

] [

.B -V

.I q

] [

.I "long or silly options"

]

.in -0.5i

.SH DESCRIPTION

.I Mp3enc

compresses audio on standard input,

normally PCM-encoded,

and produces MP3-encoded audio on standard output.

By default, the MP3 file will use `constant bit-rate' (CBR)

encoding, but that can be changed via

.B --abr

(average bitrate desired, ABR)

or

.BR -v

(variable bitrate, VBR).

.SS Options

.TF "\fB-b \fP"

.TP

.B -b

set minimum allowed

.I bitrate

in Kb/s for VBR, default 32Kb/s.

For CBR,

set the exact bitrate in Kb/s, which defaults to 128Kb/s.

.TP

.B -B

set maximum allowed

.I bitrate

in Kb/s for VBR, default 256Kb/s.

.TP

.BI -h

same as

.LR "-q 2" .

.TP

.B -m

.I mode

may be

(s)tereo,

(j)oint,

(f)orce

or

(m)ono

(default j).

.B force

forces mid/side stereo on all frames.

.TP

.B -p

add CRC error protection (adds an additional 16 bits per frame to the stream).

This seems to break playback.

.TP

.B -q

sets output quality to

.I q

(see

.BR -V ).

.TP

.B -r

input is raw pcm

.TP

.B -s

set sampling frequency of input file (in KHz) to

.IR sfreq ,

default is 44.1.

.TP

.B -v

use variable bitrate (VBR) encoding

.TP

.B -V

set quality setting for VBR to

.IR q .

Default

.I q

is 4;

9 produces lowest-quality and smallest files.

.SS Long options

.TF "\fB--resample sfreq \fP"

.TP

.BI --abr " bitrate"

sets average

.I bitrate

desired in Kb/s, instead of setting quality,

and generates ABR encoding.

.TP

.BI --resample " sfreq"

set sampling frequency of output file (in KHz) to

.IR sfreq ,

default is input sfreq.

.TP

.BI --mp3input

.I input

is an MP3 file

.

.SS Silly options

.TF --nohist

.TP

.BI -f

same as

.LR "-q 7" .

Such a deal. 

.TP

.BI -o

mark as non-original (i.e. do not set the original bit)

.TP

.BI -c

mark as copyright

.TP

.BI -k

disable sfb=21 cutoff

.TP

.BI -e " emp"

de-emphasis n/5/c

(default n)

.TP

.BI -d

allow channels to have different blocktypes

.TP

.BI -t

disable Xing VBR informational tag

.TP

.BI -a

autoconvert from stereo to mono file for mono encoding

.TP

.BI -x

force byte-swapping of input (see

.IR dd (1)

instead)

.TP

.BI -S

don't print progress report, VBR histograms

.TP

.BI --athonly

only use the ATH for masking

.TP

.BI --nohist

disable VBR histogram display

.TP

.BI --voice

experimental voice mode

.

.SH EXAMPLES

Encode a

.L .wav

file as highest-quality MP3.

.IP

.EX

games/mp3enc -q 0 -b 320

.EE

.LP

Create a fixed 128Kb/s MP3 file from a

.L .wav

file.

.IP

.EX

games/mp3enc -h <foo.wav >foo.mp3

.EE

.LP

Streaming from stereo 44.1KHz raw PCM data, encoding mono at 16KHz

(you may not need

.IR dd ):

.IP

.EX

dd -conv swab | games/mp3enc -a -r -m m --resample 16 -b 24

.EE

.SH SOURCE

.B /sys/src/games/mp3enc

.SH SEE ALSO

.IR dd (1),

.IR mp3dec (1),

.IR audio (3),

.IR cdfs (4),

.IR audio (7),

.IR juke (7),

.IR playlistfs (7)

.br

.B http://www.sulaco.org/mp3

.SH BUGS

Quality is much better than encoders based on the ISO routines,

but still not as good as the FhG encoder.

.PP

It's a GNU behemoth, lightly rehabilitated.

There are zillions of undocumented options.