[Chris Cannam] >Rubber Band is an audio time-stretching and pitch-shifting library and >utility designed for musical applications. > > http://www.breakfastquay.com/rubberband/ > >It includes a library that supports a sample-accurate multithreaded >offline mode and a real-time lock-free streaming mode; a command-line >utility program; and a LADSPA pitch-shifter plugin. Rubber Band is >Free Software under the GNU GPL.
I've just tried it at crispness levels 2 and 4 stretching 'Vesoul' by Brel to 2x duration and I have to say it does a wonderful job on the note onsets, who survive largely unsmeared (a bit better at crispness level 4, which also goes for the overall sound impression, as subjective as that may be). That's where it really outdoes the stretch utility I wrote some time ago (where the actual work is done by a Dolson phase vocoder from the CARL suite, cf. http://quitte.de/dsp/pvoc.html#stretch). Unfortunately it also has to be noted that after the onset, the voice body in rubberband's output is not sounding quite as good as with 'stretch' -- there's a faint chorus/aliasing effect, not very strong but irritating. Is the engine capable of smoothly changing the stretch factor in realtime? I've been pondering a simple looping & stretching playback solution for transcription work but the 'stretch' engine isn't flexible enough out of the box, it'd only allow a number of switchable stretch factor presets unless I put in some really serious work. Cheers, Tim _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
