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Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the + library `Frob' (a library for tweaking knobs) written by James Random Hacker. + + , 1 April 1990 + Ty Coon, President of Vice + +That's all there is to it! + diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/conduit-audio.cabal b/conduit-audio.cabal new file mode 100644 --- /dev/null +++ b/conduit-audio.cabal @@ -0,0 +1,40 @@ +name: conduit-audio +version: 0.1 +author: Michael Tolly +maintainer: miketolly@gmail.com +license: LGPL +license-file: LICENSE +category: Sound +build-type: Simple +cabal-version: >= 1.10 +homepage: http://github.com/mtolly/conduit-audio +bug-reports: http://github.com/mtolly/conduit-audio/issues +synopsis: Combinators to efficiently slice and dice audio streams +description: + @conduit-audio@ applies @conduit@'s streaming data abilities + to efficiently manipulate audio files and streams. + Simple combinator functions let you mix files together, + cut and paste sections of audio, + and apply more complicated transformations like resampling or timestretching, + all with the following properties: + . + * Tiny memory usage, proportional only to the number of simultaneous sources\/effects + . + * Uses no temporary files; everything is done in one pass + . + * Blazing fast! (for most uses) + +library + exposed-modules: + Data.Conduit.Audio + build-depends: + base >= 4.6 && < 4.8 + , conduit + , vector + hs-source-dirs: src + default-language: Haskell2010 + ghc-options: -Wall -O2 + +source-repository head + type: git + location: http://github.com/mtolly/conduit-audio diff --git a/src/Data/Conduit/Audio.hs b/src/Data/Conduit/Audio.hs new file mode 100644 --- /dev/null +++ b/src/Data/Conduit/Audio.hs @@ -0,0 +1,311 @@ +{- | +A high-level functional interface for manipulating streams of audio. +-} +module Data.Conduit.Audio +( -- * Types + AudioSource(..) +, Seconds, Frames, Rate, Channels, Duration(..) + -- * Generating audio +, silent, sine + -- * Combining audio +, concatenate, mix, merge, splitChannels + -- * Editing audio +, padStart, padEnd +, takeStart, takeEnd +, dropStart, dropEnd +, fadeIn, fadeOut +, mapSamples, gain + -- * Utility functions +, vectorFrames +, framesToSeconds, secondsToFrames +, chunkSize +, deinterleave, interleave +, integralSample, fractionalSample +) where + +import qualified Data.Vector.Storable as V +import qualified Data.Conduit as C +import Data.Conduit ((=$=)) +import qualified Data.Conduit.List as CL +import Data.Conduit.Internal (zipSources) +import Control.Monad (replicateM_, forever, when) +import Data.Maybe (fromMaybe) +import Text.Printf (printf) + +-- | An abstraction of a stream of audio. Inside is a Conduit 'C.Source' which +-- loads or generates smallish chunks of audio on demand. @m@ is the 'Monad' +-- used by the 'C.Source' to produce audio. @a@ is the type of audio samples, +-- contained in storable vectors (and thus should be 'V.Storable'). +-- Both (signed) 'Integral' and 'Fractional' sample types are supported. +data AudioSource m a = AudioSource + { source :: C.Source m (V.Vector a) + -- ^ The stream of audio chunks; samples interleaved by channel. + -- Each chunk can be any positive whole number of frames. + , rate :: Rate + , channels :: Channels + , frames :: Frames + -- ^ The stated length in frames of this audio stream. + -- Not guaranteed to be exactly frame-accurate; + -- the output of some operations like resampling or time-stretching + -- may store only approximate frame counts. + } + +-- | A duration in real time. +type Seconds = Double +-- | A frame consists of one sample for each audio channel. +type Frames = Int +-- | The number of samples per second. +type Rate = Double +-- | The number of audio channels (1 = mono, 2 = stereo, etc.) +type Channels = Int + +-- | Used for functions that accept durations in either real time or audio frames. +data Duration + = Seconds Seconds + | Frames Frames + deriving (Eq, Ord, Show, Read) + +-- | Divides the vector length by the channel count to calculate the number of audio frames. +vectorFrames :: (V.Storable a) => V.Vector a -> Channels -> Frames +vectorFrames v c = case quotRem (V.length v) c of + (len, 0) -> len + _ -> error $ + printf "Data.Conduit.Audio.vectorFrames: block length (%d) not divisible by channel count (%d)" + (V.length v) c + +-- | Uses the sample rate to convert frames to seconds. +framesToSeconds :: Frames -> Rate -> Seconds +framesToSeconds fms r = fromIntegral fms / r + +-- | Uses the sample rate to convert seconds to frames, rounding if necessary. +secondsToFrames :: Seconds -> Rate -> Frames +secondsToFrames secs r = round $ secs * r + +-- | An arbitrary size, in frames, for smallish audio chunks. +chunkSize :: Frames +chunkSize = 10000 + +-- | Generates a stream of silence with the given parameters. +silent :: (Monad m, Num a, V.Storable a) => Duration -> Rate -> Channels -> AudioSource m a +silent (Seconds secs) r c = silent (Frames $ secondsToFrames secs r) r c +silent (Frames fms) r c = let + (full, part) = quotRem fms chunkSize + fullChunk = V.replicate (chunkSize * c) 0 + partChunk = V.replicate (part * c) 0 + src = do + replicateM_ full $ C.yield fullChunk + when (part /= 0) $ C.yield partChunk + in AudioSource src r c fms + +-- | Generates a mono sine wave with the given frequency. +sine :: (Monad m, Floating a, V.Storable a) => a -> Duration -> Rate -> AudioSource m a +sine freq (Seconds secs) r = sine freq (Frames $ secondsToFrames secs r) r +sine freq (Frames fms) r = AudioSource (go 0) r 1 fms where + valueAt posn = sin $ 2 * pi * freq * (fromIntegral posn / realToFrac r) + go posn = let + left = fms - posn + in if left <= chunkSize + then C.yield $ V.generate left $ \i -> valueAt $ i + posn + else let + firstChunk = V.generate chunkSize $ \i -> valueAt $ i + posn + in C.yield firstChunk >> go (posn + chunkSize) + +-- | Connects the end of the first audio source to the beginning of the second. +-- The two sources must have the same sample rate and channel count. +concatenate :: (Monad m) => AudioSource m a -> AudioSource m a -> AudioSource m a +concatenate (AudioSource s1 r1 c1 l1) (AudioSource s2 r2 c2 l2) + | r1 /= r2 = error $ + printf "Data.Conduit.Audio.concatenate: mismatched rates (%d and %d)" r1 r2 + | c1 /= c2 = error $ + printf "Data.Conduit.Audio.concatenate: mismatched channel counts (%d and %d)" c1 c2 + | otherwise = AudioSource (s1 >> s2) r1 c1 (l1 + l2) + +padStart, padEnd :: (Monad m, Num a, V.Storable a) => Duration -> AudioSource m a -> AudioSource m a +-- | Adds silence to the start of the audio stream. +padStart d src@(AudioSource _ r c _) = concatenate (silent d r c) src +-- | Adds silence to the end of the audio stream. +padEnd d src@(AudioSource _ r c _) = concatenate src (silent d r c) + +-- | Splits an audio stream into several, each providing a single channel of the original stream. +splitChannels :: (Monad m, V.Storable a) => AudioSource m a -> [AudioSource m a] +splitChannels (AudioSource src r c l) = do + i <- [0 .. c - 1] + let src' = src =$= CL.map (\v -> deinterleave c v !! i) + return $ AudioSource src' r 1 l + +-- | Mixes two audio streams together by adding them samplewise. +-- The two streams must have the same sample rate and channel count. +-- It is recommended to only mix floating-point sample types. +-- If you mix integral types and the result goes outside of the type's range, +-- the result will not be a normal \"clipping\" effect, but will instead overflow, +-- producing glitchy audio. +mix :: (Monad m, Num a, V.Storable a) => AudioSource m a -> AudioSource m a -> AudioSource m a +mix (AudioSource s1 r1 c1 l1) (AudioSource s2 r2 c2 l2) + | r1 /= r2 = error $ + printf "Data.Conduit.Audio.mix: mismatched rates (%d and %d)" r1 r2 + | c1 /= c2 = error $ + printf "Data.Conduit.Audio.mix: mismatched channel counts (%d and %d)" c1 c2 + | otherwise = AudioSource + (combineAudio c1 c2 s1 s2 =$= CL.map (uncurry $ V.zipWith (+))) + r1 c1 (max l1 l2) + +-- | Combines the channels of two audio streams into a single source with all the channels. +-- The two streams must have the same sample rate, but can have any number of channels. +merge :: (Monad m, Num a, V.Storable a) => AudioSource m a -> AudioSource m a -> AudioSource m a +merge (AudioSource s1 r1 c1 l1) (AudioSource s2 r2 c2 l2) + | r1 /= r2 = error $ + printf "Data.Conduit.Audio.merge: mismatched rates (%d and %d)" r1 r2 + | otherwise = AudioSource + (combineAudio c1 c2 s1 s2 =$= CL.map + (\(p1, p2) -> interleave $ deinterleave c1 p1 ++ deinterleave c2 p2)) + r1 (c1 + c2) (max l1 l2) + +-- | Applies a function to every sample in the audio stream. +mapSamples :: (Monad m, V.Storable a, V.Storable b) => + (a -> b) -> AudioSource m a -> AudioSource m b +mapSamples f (AudioSource s r c l) = AudioSource (s =$= CL.map (V.map f)) r c l + +-- | Multiplies all the audio samples by the given scaling factor. +-- It is best to use this function on floating-point sample types, +-- for the same reasons that apply to 'mix'. +gain :: (Monad m, Num a, V.Storable a) => a -> AudioSource m a -> AudioSource m a +gain d = mapSamples (* d) + +-- | Fades the audio from start (silent) to end (original volume). +-- This function relies on the 'frames' value stored with the stream. +fadeIn :: (Monad m, Ord a, Fractional a, V.Storable a) => AudioSource m a -> AudioSource m a +fadeIn (AudioSource s r c l) = let + go i = C.await >>= \mx -> case mx of + Nothing -> return () + Just v -> let + fader = V.generate (V.length v) $ \j -> + min 1 $ fromIntegral (i + quot j c) / fromIntegral l + in C.yield (V.zipWith (*) v fader) >> go (i + vectorFrames v c) + in AudioSource (s =$= go 0) r c l + +-- | Fades the audio from start (original volume) to end (silent). +-- This function relies on the 'frames' value stored with the stream. +fadeOut :: (Monad m, Ord a, Fractional a, V.Storable a) => AudioSource m a -> AudioSource m a +fadeOut (AudioSource s r c l) = let + go i = C.await >>= \mx -> case mx of + Nothing -> return () + Just v -> let + fader = V.generate (V.length v) $ \j -> + 1 - (min 1 $ fromIntegral (i + quot j c) / fromIntegral l) + in C.yield (V.zipWith (*) v fader) >> go (i + vectorFrames v c) + in AudioSource (s =$= go 0) r c l + +-- | Takes no more than the given duration of audio from the start of the stream. +takeStart :: (Monad m, V.Storable a) => Duration -> AudioSource m a -> AudioSource m a +takeStart (Seconds secs) src = takeStart (Frames $ secondsToFrames secs $ rate src) src +takeStart (Frames fms) (AudioSource src r c l) = let + go left = C.await >>= \mx -> case mx of + Nothing -> return () + Just v -> let + len = V.length v + in case compare left len of + EQ -> C.yield v + LT -> C.yield $ V.take left v + GT -> C.yield v >> go (left - len) + in AudioSource (src =$= go (fms * c)) r c (min l fms) + +-- | Drops the given duration of audio from the start of the stream. +dropStart :: (Monad m, V.Storable a) => Duration -> AudioSource m a -> AudioSource m a +dropStart (Seconds secs) src = dropStart (Frames $ secondsToFrames secs $ rate src) src +dropStart (Frames fms) (AudioSource src r c l) = let + go left = C.await >>= \mx -> case mx of + Nothing -> return () + Just v -> let + len = V.length v + in case compare left len of + EQ -> CL.map id + LT -> C.yield (V.drop left v) >> CL.map id + GT -> go (left - len) + in AudioSource (src =$= go (fms * c)) r c (max 0 $ l - fms) + +takeEnd, dropEnd :: (Monad m, V.Storable a) => Duration -> AudioSource m a -> AudioSource m a +-- | Takes no more than the given duration of audio from the end of the stream. +-- This function relies on the 'frames' value stored with the stream. +takeEnd (Frames fms) src = dropStart (Frames $ frames src - fms) src +takeEnd (Seconds secs) src = takeEnd (Frames $ secondsToFrames secs $ rate src) src +-- | Drops the given duration of audio from the end of the stream. +-- This function relies on the 'frames' value stored with the stream. +dropEnd (Frames fms) src = takeStart (Frames $ frames src - fms) src +dropEnd (Seconds secs) src = dropEnd (Frames $ secondsToFrames secs $ rate src) src + +-- | Given a vector with interleaved samples, like @[L0, R0, L1, R1, ...]@, +-- converts it into @[[L0, L1, ...], [R0, R1, ...]]@. +deinterleave :: (V.Storable a) => Channels -> V.Vector a -> [V.Vector a] +deinterleave n v = do + let len = V.length v `div` n + i <- [0 .. n - 1] + return $ V.generate len $ \j -> v V.! (n * j + i) + +-- | Opposite of 'deinterleave'. +-- All the input vectors should have the same length. +interleave :: (V.Storable a) => [V.Vector a] -> V.Vector a +interleave vs = let + n = length vs + in V.generate (sum $ map V.length vs) $ \i -> let + (q, r) = quotRem i n + in (vs !! r) V.! q + +-- | Combines two audio streams to produce pairs of same-length (in frames) chunks. +-- If one stream is shorter, its end will be padded with silence to match the longer one. +-- This function is used to implement 'mix' and 'merge'. +combineAudio + :: (Num a, V.Storable a, Monad m) + => Int + -> Int + -> C.Source m (V.Vector a) + -> C.Source m (V.Vector a) + -> C.Source m (V.Vector a, V.Vector a) +combineAudio c1 c2 s1 s2 = let + justify src = (src =$= CL.map Just) >> forever (C.yield Nothing) + await' = C.await >>= \mx -> case mx of + Nothing -> error + "Data.Conduit.Audio.combineAudio: internal error! reached end of infinite stream" + Just x -> return x + in zipSources (justify s1) (justify s2) =$= let + loop = await' >>= \pair -> case pair of + (Nothing, Nothing) -> return () + (Just v1, Nothing) -> let + v2 = V.replicate (vectorFrames v1 c1 * c2) 0 + in C.yield (v1, v2) >> loop + (Nothing, Just v2) -> let + v1 = V.replicate (vectorFrames v2 c2 * c1) 0 + in C.yield (v1, v2) >> loop + (Just v1, Just v2) -> case compare (vectorFrames v1 c1) (vectorFrames v2 c2) of + EQ -> C.yield (v1, v2) >> loop + LT -> let + (v2a, v2b) = V.splitAt (vectorFrames v1 c1 * c2) v2 + in C.yield (v1, v2a) >> await' >>= \(next1, next2) -> do + C.leftover (next1, Just $ v2b V.++ fromMaybe V.empty next2) + loop + GT -> let + (v1a, v1b) = V.splitAt (vectorFrames v2 c2 * c1) v1 + in C.yield (v1a, v2) >> await' >>= \(next1, next2) -> do + C.leftover (Just $ v1b V.++ fromMaybe V.empty next1, next2) + loop + in loop + +-- See http://blog.bjornroche.com/2009/12/int-float-int-its-jungle-out-there.html +-- for a discussion of different int/float sample conversion methods. +-- The ones below multiply/divide by 0x7FFF (or equivalent). +-- Int16 -> Float -> Int16 conversions are transparent: +-- all (\i -> i == integralSample (fractionalSample i :: Float)) [minBound :: Int16 .. maxBound] + +-- | Converts fractional samples in the range @[-1, 1]@ to integral samples +-- in a two's-complement type. Fractional samples beyond that range are clamped. +integralSample :: (RealFrac a, Integral b, Bounded b) => a -> b +integralSample x + | x <= (-1) = minBound + | x >= 1 = maxBound + | otherwise = let + result = round $ x * fromIntegral (maxBound `asTypeOf` result) + in result + +-- | Converts integral samples in a two's-complement type to fractional +-- samples in the range @[-1, 1]@. +fractionalSample :: (Integral a, Bounded a, Fractional b) => a -> b +fractionalSample x = fromIntegral x / fromIntegral (maxBound `asTypeOf` x)