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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;
0 produces highest-quality and largest files, and
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.
|
