Free audio transcoding software for linux

Transcode is a suite of command line utilities for transcoding video and audio codecs, and for converting beween different container formats. Transcode can decode and encode many audio and video formats, e.g.
- MPEG-1/2
- MPEG-4(-part 3) (also DivX and XviD variants)
- Quicktime / MPEG-PS (dvd) (decode only)
- MPEG-1-layer-1/2/3 audio
- AC3 audio
Transcode has a variety of video and audio pre and post-processing filters, including (but not limited to):
- video de-interlacing
- audio resampling
- framerate conversion
- smoothing
- cutting
Transcode can import DVDs on-the-fly, or record from Video4Linux (including V4L2 video capturing) devices.
A number of modules are included to enable import of DVDs on-the-fly, Video4Linux (including V4L2 video capturing), MPEG elementary streams (ES) or program streams (VOB), MPEG1/2/4 video, Digital Video (DV), YUV4MPEG streams, Nuppel Video (NUV), quicktime (MOV), MPEG audio layer-1/2/3, WAVE, DIVX, MJPEG, and raw or compressed (pass-through) video frames.
A number of export modules for enable writing DivX ;-), DivX 4.02/5.xx, XviD, Digital Video, MPEG-1/2 or uncompressed AVI files with MPEG, AC3 (pass-through) or PCM audio. More file formats and codecs for audio/video import are supported by the MPlayer and avifile import modules (exporting with avifile is restricted to video codecs, with MPEG/PCM or AC3 (pass-through) audio provided by transcode). Limited DVD subtitle rendering is also available.
Its modular concept is intended to provide flexibility and easy user extensibility to include other video/audio codecs or file types. A set of tools is available to extract, demultiplex and decode the sources into raw video/audio streams for import, non AVI-file export modules for writing single frames (PPM) or YUV4MPEG streams, auto-probing and scanning your sources and to enable post-processing of AVI files, including header fixing, merging multiple files or splitting large AVI files to fit on a CD.
Transcode runs on UN*X like systems like Linux, BSD, and MacOSX.
Transcode loads shared library modules that are responsible for feeding it with raw streams and encoding the frames:
The Import Modules for audio/video decoding are loaded with dlopen system call and are responsible for starting the video and audio streams (directly or via the popen system call) and have a single function interface to the main program. The import is handled by a thread that buffers the video/audio frames.
The main program transcode currently performs a number of simple video/audio frame manipulations (in this order) or allows simple pass-through of raw frame data:
Video:
- cut out arbitray frame region for processing
- de-interlace video frame
- fast enlarging of video width/height by a multiple of 32 rows/column up to 1024x768
- fast reduction of video width/height by a multiple of 32 rows/column
- high-quality resizing with filter
- cut out arbitray frame region for encoding
- rescale (downsample) video width/height by a power of 2
- flip video frame upside down
- mirror image of video frame
- swap R and B bytes in video frame
- transform to b/w video frame
- apply gamma correction
- anti-alias video frame
Audio:
- change the volume of the audio stream
- resample audio stream
- swap byte order in audio stream
- sync video with audio frames (V=0|A=N, V=1|A=N+1,...)
- Filter Plugins:
- Additional effects are available via external filter plugins loaded with option "-J".
The Export Modules for audio/video encoding are loaded via the dlopen system call and the encoder loop is started for the selected frames. In most cases audio and video are handled by the same module.
Enhancements:
- This release includes only critical hotfixes.
- The main highlight is compatibilty with newer releases of ffmpeg libraries.
- Some filters have been updated.

Audio::XMMSClient is a Perl interface to the xmms2 music player.

SYNOPSIS

use Audio::XMMSClient;

$c = Audio::XMMSClient->new( $name );
$c->connect;

my $r = $c->playback_status;
$r->wait;
print $r->value;

This module provides a perl interface to the xmms2 client library. It currently lacks a good documentation, but the turorial directory provides some nice and well explained examples to get you started for now.

Audio collection script is a script which can help you manage collections of audio files. For example, I have a directory with all my audio files in it, sorted by band/album. I also have an audio collections directory. Within that directory I have a few list files which contain patterns for songs that should be part of that collection. The script generates or updates a subdirectory for each list file present and creates links within those directories to all music files from my main audio directory that match the patterns in the list file.

An example:

Your music files are in /audio
Your collections are in /audio-collections
The file /audio-collections/funny.list has the following lines:

/audio-collections/funny/
#the next line matches all songs within a tripod directory
tripod/
monty*python
kevin*bloody*wilson
bill*clinton*miss*lewinsky*and*i

When run, it will process each .list file in the current directory. So for this example, when run from /audio-collections, it will create or clean out the directory /audio-collections/funny and create links inside it for any files found within /audio which match the specified patterns.

The first line in each list file specifies the directory to create and use for the links. The patterns in the file will match on the full path of a song.

Note: I am pretty sure it would not be a good path to put your collections inside your main audio directory.

Audio::Mad is a Perl interface to the mad MPEG decoder library.

SYNOPSIS

use Audio::Mad qw(:all);

my $stream = new Audio::Mad::Stream();
my $frame = new Audio::Mad::Frame();
my $synth = new Audio::Mad::Synth();
my $timer = new Audio::Mad::Timer();
my $resample = new Audio::Mad::Resample(44100, 22050);
my $dither = new Audio::Mad::Dither();

my $buffer = join(, );
$stream->buffer($buffer);

FRAME: {
if ($frame->decode($stream) == -1) {
last FRAME unless ($stream->err_ok());

warn "decoding error: " . $stream->error();
next FRAME;
}

$synth->synth($frame);
my $pcm = $dither->dither($resample->resample($synth->samples()));

print $pcm;
next FRAME;
}

This module is an attempt to provide a perl interface to the MAD (MPEG Audio Decoder) library, written by Robert Leslie. It has been designed to be 100% object oriented, and to follow the MAD interface as closely as possible.

So far, most of the MAD library, plus two companion modules are provided as part of the interface. Seperate documentation is provided in perldoc for all of the modules in the Audio::Mad framework.

Audio::AMR::Decode is a Perl extension do decode .amr files.

SYNOPSIS

use Audio::AMR::Decode;
Audio::AMR::Decode::amr2raw(infile.amr, outfile.pcm);

This module will attempt to decode an amr encoded audio file to a raw pcm audio encoded file.

The package contains C-source files for the optimized fixed-point speech decoder. The optimized fixed-point speech decoder is bit-exact with 3GPP TS 26.073 fixed-point speech decoder version 4.1.0.

Audio:PSID is a Perl module to handle SID files (Commodore-64 music files).

SYNOPSIS

use Audio::SID;

$mySID = new Audio::SID(-filename => Test.sid) or die "Whoops!";

print "Title = " . $mySID->get(title) . "n";

print "MD5 = " . $mySID->getMD5();

$mySID->set(author => LaLa,
title => Test2,
released => 2001 Hungarian Music Crew);

$mySID->validate();
$mySID->write(-filename => Test2.sid) or die "Couldnt write file!";

@array = $mySID->getFieldNames();
print "Fieldnames = " . join( , @array) . "n";

This module is designed to handle SID files (usually bearing a .sid extension), which are music player and data routines converted from the Commodore-64 computer with an additional informational header prepended. For further details about the exact file format, see description of all SID fields in the SID_file_format.txt file included in the module package.

Audio::Ecasound is a Perl binding to the ecasound sampler, recorder, fx-processor.

SYNOPSIS
One function interface:
use Audio::Ecasound qw(:simple);

eci("cs-add play_chainsetup");
eci("c-add 1st_chain");
eci("-i:some_file.wav");
eci("-o:/dev/dsp");
# multiple n separated commands
eci("cop-add -efl:100
# with comments
cop-select 1
copp-select 1
cs-connect");
eci("start");
my $cutoff_inc = 500.0;
while (1) {
sleep(1);
last if eci("engine-status") ne "running";

my $curpos = eci("get-position");
last if $curpos > 15;

my $next_cutoff = $cutoff_inc + eci("copp-get");
# Optional float argument
eci("copp-set", $next_cutoff);
}
eci("stop");
eci("cs-disconnect");
print "Chain operator status: ", eci("cop-status");

Object Interface

use Audio::Ecasound;

my $e = new Audio::Ecasound;
$e->on_error();
$e->eci("cs-add play_chainsetup");
# etc.
Vanilla Ecasound Control Interface (See Ecasounds Programmer Guide):
use Audio::Ecasound qw(:std);

command("copp-get");
$precise_float = last_float() / 2;
command_float_arg("copp-set", $precise_float);
warn last_error() if error();
IAM Interface, pretend interactive mode commands are functions.
use Audio::Ecasound qw(:iam :simple);

# iam commands as functions with s/-/_/g
my $val = copp_get;
copp_set $val+0.1; # floats are stringified so beware
eci("-i /dev/dsp"); # not all commands are exported

Audio::Ecasound provides perl bindings to the ecasound control interface of the ecasound program. You can use perl to automate or interact with ecasound so you dont have to turn you back on the adoring masses packed into Wembly Stadium.
Ecasound is a software package designed for multitrack audio processing. It can be used for audio playback, recording, format conversions, effects processing, mixing, as a LADSPA plugin host and JACK node. Version >= 2.2.X must be installed to use this package. "SEE ALSO" for more info.