triadabicycle.blogg.se - september 2022

Pitch shifting is acheived via windowed FFT analysis of the input file, then resynthesis into the output file via oscillator bank resynthesis. The above example takes strings.aif, and stretches it to be 10 times the original length using 4096 FFT bands with an overlap factor of 4, using a kaiser windowing function Pitch Shifting gopvoc time -i strings.aif -f strings_x10.aif -b 4096 -o 4 -s 10 -w kaiser Program output will indicate of your requested -s flag has been limited. Unlike SoundHack, gopvoc will cap the multiplier within this limit instead of crashing due to a division by zero. The maximum or minimum allowed -s scale multiplier is dependent on the FFT window size which in turn is dependent on the number of FFT bands requested by the -b flag and the overlap factor given by the -o flag. Note that the original SoundHack could crash given certain program states based on extreme stretching multipliers. Time stretching is acheived via windowed FFT analysis of the input file, then resynthesis into the output file via overlap add resynthesis. Time stretching can do phase locking during resynthesis, to enable it: Quiet flag (suppress stdout information and progress bar): Resynthesis gating threshold db level below maximum (optional):

Resynthesis gating minimum db level (optional): Windowing function for FFT processing (must be one of: rectangle, hamming, vonhann, kaiser, sinc, triangle, ramp): For pitch shifting, the pitch shift multiplier): Scale factor (for time stretching, the amount to mutliply input duration by. Overlap factor (must be one of 0.5, 1, 2, 4): To see options and defaults for each command:īoth time stretching and pitch shifting use the following common set of flags:

Gopvoc has two modes of operation, time stretching and pitch shifting. gopvoc pitch -i strings_cut.aif -f strings_cut-p2up-ohalf.aif -s 4 -o. Pitch shift 4 (up two octaves), overlap factor. gopvoc pitch -i strings_cut.aif -f strings_cut-p2down-ohalf.aif -s. Pitch shift 0.25 (down two octaves), overlap factor. gopvoc time -i strings_cut.aif -f strings_cut-s100-o4.aif -s 100 -o 4 Pitch Shifting Output Example Time stretch x100, overlap factor 4 output gopvoc time -i strings_cut.aif -f strings_cut-s100-ohalf.aif -s 100 -o.

Time stretch x100, overlap factor 0.5 output Original sample used as input for all examples Time Stretching Output Example

gopvoc can analyze up to 8192 FFT bands.

Before writing to disk, gopvoc clips any samples to the max or min allowed value for the given bit depth.

gopvoc handles output clipping differently than SoundHack.

gopvoc does not allow a scaling function, it only accepts a single value for scale factor.

gopvoc time stretching can only take a multiplier scale factor for time instead of a target output duration.

gopvoc pitch shifting can only take a multiplier scale factor for pitch (octave lower is scale factor of 0.5, octave higher is 2.0, etc).

gopvoc can only read and write AIFF and WAV files.

gopvoc can process AIFF/WAV files with an arbitrary number of channels.

gopvoc uses a slightly different vonn Hann window function than SoundHack.

The way the "best" interpolation and decimation rates are determined is slightly different than the original SoundHack.

gopvoc doesn't allow time stretching beyond the maximum or minimum as determined by the given inputs, see below.

Unlike the original SoundHack, this port does not have a UI and must be used on the command line. This is a Go port of the phase vocoding analysis/resynthesis routines from Tom Erbe's program "SoundHack".