Encode PCM Audio data to MP3 in Raku using a binding to liblame
This module provides a simple binding to "lame" an MP3 encoding library.
With this you can encode PCM data to MP3 at any bitrate or quality supported by the lame library.
The interface is somewhat simplified in comparison to that of lame and some of the esoteric or rarely used features may not be supported.
Because marshalling large arrays and buffers between Raku space and the native world may be too slow for some use cases the interface provides for passing and returning native CArrays (and their sizes) for the use of other native bindings (e.g. Audio::Sndfile, Audio::Libshout) where speed may prove important, which , for me at least, is quite a common use-case. The 'raku-lame-encode' example demonstrates this way of using the interface.
For interest the first thing I encoded was:
which is a remix I made of a track by the lovely Aaron Udy.
You will need to have "lame" installed on your system in order to be able to use this. Most Linux distributions offer it as a package, but because there are certain patent issues surrounding the MP3 codec some distributions may either have it in an optional repository or not have it at all.
If you are on some platform that doesn't provide lame as a package then you may be able to install it from source:
I am however unlikely to be able to offer help with installing it this way, also bear in mind that if you install a newer version than I have to test with then this may not work.
Assuming you have a working Rakudo installation you should be able to install this with zef :
# From the source directory zef install . # Remote installation zef install Audio::Encode-LameMP3
The tests take a little longer than I would like largely because there's quite a lot of file I/O involved.
Suggestions/patches are welcomed via github at
I have tested this and found it to work with my installation of libmp3lame so it should work anywhere else the library is installed, if however you experience a problem with the encoding, please test with the 'lame' binary that is installed with libmp3lame before reporting a bug. Obviously because the actual encoding is done by the native library, I'm not able to comment on the perceived quality or otherwise of the results.
This library only binds to a "lame" installation you may have on your system, any licensing issues regarding the MP3 codec relate to the implementation of the codec and I cannot answer questions related to the licensing of that library.
Please see the LICENCE file in the distribution regarding the licence for this library module.
© Jonathan Stowe 2015 - 2021