The main window
by Nasca Octavian PAUL
This is a program for stretching the audio. It is suitable only for extreme sound stretching of the audio (like 50x) and for applying special effects by "spectral smoothing" the sounds. It can transform any sound/music to a texture. The program is Open-Source and it's released under the version 2 of the General Public License. You can download the source code for Linux or the Windows binaries.
Please note that this is suitable only for extreme time stretching (e.g. if have a melody of 3 minutes and you want to listen it in 3 hours). If you want "less extreme" time stretching, you can use a program which contains the SoundTouch library.
It produces high quality extreme sound stretching. While most sound stretching software sounds bad when trying to stretch the sounds a lot, this one is optimized for extreme sound stretching. So, the stretch amount is unlimited.
You can play the stretched sound in real-time (including the possibility to "freeze" the sound) or you can render the whole sound or a part of it to audio files
It has many post-processing effects, like: filters, pitch/frequency shifters
Support for WAV, OGG VORBIS files and MP3 files
It is a Free Software
Original sound, generated by ZynAddSubFX
You can download the source code for Linux or binary for Windows from here(click on the “files” tab).
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The main window |
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The Render window |
Before starting, you need to open a WAV, OGG VORBIS or MP3 file. You can open it by using the file menu, by launching the program with a command-line argument or (on linux systems) by drag a file from explorer and drop it on the filename bar(under the menu).
The main window has two main controls: the stretch amount and the audio window.
There are three modes:
The "Stretch" mode - may stretch up to 10,000 times
The "HyperStretch" mode - may stretch up to 1,000,000,000 times
The "Shorten" mode - it reduces the length of the sound
You can precisely set the amount by pressing the "S" button.
This program doesn't process the sound as a single piece: it cuts the sound in small pieces process them. Each small piece is called a "window". The size of the windows controls the size of the window in samples, which affects the frequency and the time resolution of the resulting sounds. The small windows have good time resolution, but poor frequency resolution. Also, large windows has poor time resolution, but they has great frequency resolution. Usually, a window of 7-12k is good for most music. Very big windows (> 100k) can be used for special effects (for smearing the sound very much and transforming it into a sound-texture even if the stretch is closer to 1.0).
If the playback is on and you change the window size, you have to press play again to have effect on the current playback.
Also, the window has another control, which is the type of the window. It set a trade-off between frequency resolution and the noise. The Rectangular/Hamming types has the best frequency resolution, but they produces a lot of noises. The Blackman types produces almost no noise, but has a slightly lower frequency resolution.
You can render/play the sound in real-time, by using the playback buttons in the lower parts of the windows.
the play button starts the sound and in the preprocessing stage is colored in red color. When the playing starts, it is colored in green. If you right-click it, the audio is bypassed and you'll hear the original sound.
the freeze button "freezes" the sound (sets the stretching amount to "infinite")
the pause button pauses the sound
the stop button
the percents slider shows/sets the playback position (in percents). It might be a 1-2 seconds delay when clicking on it before the audio seek.
It is possible to use post-processing filters for the audio.
Harmonics - this effect removes everything, except a frequency and it's harmonics. The controls are: fundamental frequency, bandwidth of each harmonics(cents), number of harmonics and if the harmonics has bell-shaped curve(gauss)
Pitch shift - shift a pitch by a certain amount of cents
Freq shift - shift all frequencies by a certain amount of hertz (usually, this produces a dissonant effect)
Octave Mixer - pitch-shift the audio by multiples of octaves and mixes the result. The controls are: -2 (down 2 octave mix), -1 (octave down mix), 0 (dry mix), 1 (one octave up mix), 1.5 (the third harmonic mix), 2 (two octave up mix)
Filter - Bandpass/Lowpass/Highpass/Bandstop/Smooth filters. The controls are: Freq1&Freq2 (the edge frequencies), Bstop (the filter rejects everything between the Freq1&Freq2; if this is unchecked, only frequencies between Freq1&Freq2 remains). DHF is the amount of the smooth filter (damps higher frequencies)
Compress - Compress the loudness of the sound. At the maximum value, the loudness of the output sounds is constant
Vol - Output volume
You can select the desired part of the sound and render it to disk.
The select pos1 and select pos2 sets the limits of the selection from the percents(playback) slider.
While rendering, the interface will be a bit less responsive, but you can still play the current sound or select and play another sound.
It sounds very good on stretching classical music(for finding small errors on choirs :) ). I like very much listening to Vangelis using this effect. I recomand you to try to listen "Movement 1" from "El Greco" album from the 9:00 minutes stretched by 30x, using a window of 10k samples. Also, you can try the "Monastery of La Rabida" soundtrack from the "Conquest of paradise" album.
improving the Shorten method
add possibility to use larger windows on output on stretching, to allow more precise post-processing
sometimes the playback is choppy. Stop the sound and restart the play as a work-around
the shorten mode is a bit buggy (not finished). Also, it requires a lot memory for very small values, so it is limited to 0.1x
on very large sizes of the window (like few M), it can use the swap a lot and slow down the system(not quite a bug)
20060527(0.0.1)
- First release
20060530(0.0.2)
- Ogg Vorbis output support
- Added a wxWidgets graphical user interface
20060812(1.000)
- Removed the wxWidgets GUI and added a FLTK GUI
- Added real-time processing/player
- Added input support for Ogg Vorbis files
- Improved the stretch algorithm and now the amount of stretch is unlimited (and on big stretch amounts, you don't need additional memory)
- Added "Freeze" button to the player
- It is possible to render to file only a selected part of the sound
- Other improvements
20060905(1.024)
- Added MP3 support for input
- Added bypass mode (if you click play with the right mouse button)
- Improved the precision of the position slider (now it shows really what's currenly playing)
- Added the possibility to set the stretch amount by entering the numeric value
- Added pause mode and volume control
- Added post-processing of the spectrum(pitch/frequency shift, octave mixer, compress,filter,harmonics)
- Command line parameter for input filename
- The file can be dragged from the explorer to the file text to open it
Contact:
zynaddsubfx AT YAHOO COM
