FEATURES.in

The current release handles the following audio file formats:
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* Raw files in various binary formats
* Raw textual data
* Amiga 8svx files
* Apple/SGI AIFF files
* SUN .au files
** PCM, u-law, A-law
** G7xx ADPCM files (read only)
** mutant DEC .au files
** NeXT .snd files
* AVR files
* CDDA (Compact Disc Digital Audio format)
* CVS and VMS files (continuous variable slope)
* Grandstream ring-tone files
* GSM files
* HTK files
* LPC-10 files
* Macintosh HCOM files
* Amiga MAUD files
* AMR-WB & AMR-NB (with optional libamrwb & libamrnb libraries)
* MP2/MP3 (with optional libmad, libtwolame and libmp3lame libraries)
* Opus files (read only; with optional Opus libraries)
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* Ogg Vorbis files (with optional Ogg Vorbis libraries)
* FLAC files (with optional libFLAC)
* IRCAM SoundFile files
* NIST SPHERE files
* Turtle beach SampleVision files
* Sounder & Soundtool (DOS) files
* Yamaha TX-16W sampler files
* SoundBlaster .VOC files
* Dialogic/OKI ADPCM files (.VOX)
* Microsoft .WAV files
** PCM, floating point
** u-law, A-law, MS ADPCM, IMA (DMI) ADPCM
** GSM
** RIFX (big endian)
* WavPack files (with optional libwavpack library)
* Psion (palmtop) A-law WVE files and Record voice notes
* Maxis XA Audio files
** EA ADPCM (read support only, for now)
* Pseudo formats that allow direct playing/recording from most audio devices
* The "null" pseudo-file that reads and writes from/to nowhere
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The audio effects/tools included in this release are as follows:

* Tone/filter effects
** allpass: RBJ all-pass biquad IIR filter
** bandpass: RBJ band-pass biquad IIR filter
** bandreject: RBJ band-reject biquad IIR filter
** band: SPKit resonator band-pass IIR filter
** bass: Tone control: RBJ shelving biquad IIR filter
** equalizer: RBJ peaking equalisation biquad IIR filter
** firfit+: FFT convolution FIR filter using given freq. response (W.I.P.)
** highpass: High-pass filter: Single pole or RBJ biquad IIR
** hilbert: Hilbert transform filter (90 degrees phase shift)
** lowpass: Low-pass filter: single pole or RBJ biquad IIR
** sinc: Sinc-windowed low/high-pass/band-pass/reject FIR
** treble: Tone control: RBJ shelving biquad IIR filter

* Production effects
** chorus: Make a single instrument sound like many
** delay: Delay one or more channels
** echo: Add an echo
** echos: Add a sequence of echos
** flanger: Stereo flanger
** overdrive: Non-linear distortion
** phaser: Phase shifter
** repeat: Loop the audio a number of times
** reverb: Add reverberation
** reverse: Reverse the audio (to search for Satanic messages ;-)
** tremolo: Sinusoidal volume modulation

* Volume/level effects
** compand: Signal level compression/expansion/limiting
** contrast: Phase contrast volume enhancement
** dcshift: Apply or remove DC offset
** fade: Apply a fade-in and/or fade-out to the audio
** gain: Apply gain or attenuation; normalise/equalise/balance/headroom
** loudness: Gain control with ISO 226 loudness compensation
** mcompand: Multi-band compression/expansion/limiting
** norm: Normalise to 0dB (or other)
** vol: Adjust audio volume

* Editing effects
** pad: Pad (usually) the ends of the audio with silence
** silence: Remove portions of silence from the audio
** splice: Perform the equivalent of a cross-faded tape splice
** trim: Cuts portions out of the audio
** vad: Voice activity detector

* Mixing effects
** channels: Auto mix or duplicate to change number of channels
** divide+: Divide sample values by those in the 1st channel (W.I.P.)
** remix: Produce arbitrarily mixed output channels
** swap: Swap pairs of channels

* Pitch/tempo effects
** bend: Bend pitch at given times without changing tempo
** pitch: Adjust pitch (= key) without changing tempo
** speed: Adjust pitch & tempo together
** stretch: Adjust tempo without changing pitch (simple alg.)
** tempo: Adjust tempo without changing pitch (WSOLA alg.)

* Mastering effects
** dither: Add dither noise to increase quantisation SNR
** rate: Change audio sampling rate

* Specialised filters/mixers
** deemph: ISO 908 CD de-emphasis (shelving) IIR filter
** earwax: Process CD audio to best effect for headphone use
** noisered: Filter out noise from the audio
** oops: Out Of Phase Stereo (or `Karaoke') effect
** riaa: RIAA vinyl playback equalisation

* Analysis `effects'
** noiseprof: Produce a DFT profile of the audio (use with noisered)
** spectrogram: graph signal level vs. frequency & time (needs `libpng')
** stat: Enumerate audio peak & RMS levels, approx. freq., etc.
** stats: Multichannel aware `stat'

* Miscellaneous effects
** ladspa: Apply LADSPA plug-in effects e.g. CMT (Computer Music Toolkit)
** synth: Synthesise/modulate audio tones or noise signals
** newfile: Create a new output file when an effects chain ends.
** restart: Restart 1st effects chain when multiple chains exist.

* Low-level signal processing effects
** biquad: 2nd-order IIR filter using externally provided coefficients
** downsample: Reduce sample rate by discarding samples
** fir: FFT convolution FIR filter using externally provided coefficients
** upsample: Increase sample rate by zero stuffing

  + Experimental or incomplete effect; may change in future.

Multiple audio files can be combined (and then further processed with
effects) using any one of the following combiner methods:

* concatenate
* mix
* merge: E.g. two mono files to one stereo file
* sequence: For playing multiple audio files/streams