diff --git a/ChangeLog.md b/ChangeLog.md
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+++ b/ChangeLog.md
@@ -0,0 +1,7 @@
+# Changelog for opusfile
+
+## Unreleased changes
+
+## [0.1.0.0] Initial import
+
+[0.1.0.0]: https://gitlab.com/dpwiz/opusfile/-/tree/v0.1.0.0
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
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+Copyright Alexander Bondarenko (c) 2020
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Alexander Bondarenko nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,14 @@
+# opusfile
+
+https://opus-codec.org/
+
+> Opus is a totally open, royalty-free, highly versatile audio codec.
+> Opus is unmatched for interactive speech and music transmission over the Internet,
+> but is also intended for storage and streaming applications.
+
+My intention were to use the Opus codec for game assets with OpenAL.
+There's `examples/openal-playfile` exactly for this.
+
+You'll need `libopusfile-dev` or something like that for your distro.
+
+Add to package dependencies and import `Sound.OpusFile` qualified.
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/examples/openal-playfile/Main.hs b/examples/openal-playfile/Main.hs
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--- /dev/null
+++ b/examples/openal-playfile/Main.hs
@@ -0,0 +1,67 @@
+module Main where
+
+import Control.Concurrent (threadDelay)
+import Data.StateVar (($=))
+import System.Environment (getArgs)
+import Text.Printf (printf)
+
+import qualified Data.ByteString as ByteString
+import qualified Foreign
+import qualified Sound.OpenAL as OpenAL
+import qualified Sound.OpusFile as OpusFile
+
+main :: IO ()
+main = getArgs >>= \case
+  [] ->
+    putStrLn "Usage: openal-playfile <filename.opus>"
+  files ->
+    withAL $
+      mapM_ playFile files
+
+playFile :: FilePath -> IO ()
+playFile filename = do
+  (time, source) <- sourceOpusFile filename
+  OpenAL.play [source]
+  putStrLn $ printf "Playing %s (%.1f s)" (show filename) time
+  threadDelay $ truncate (time * 1000000)
+
+sourceOpusFile :: FilePath -> IO (Double, OpenAL.Source)
+sourceOpusFile filePath = do
+  Right file <- ByteString.readFile filePath >>= OpusFile.openMemoryBS
+  pcm <- OpusFile.decodeInt16 file
+  OpusFile.free file
+
+  buffer <- OpenAL.genObjectName
+  Foreign.withForeignPtr (OpusFile.pcmData pcm) \ptr -> do
+    let
+      mreg =
+        OpenAL.MemoryRegion ptr (fromIntegral $ OpusFile.pcmSize pcm)
+
+      alFormat =
+        case OpusFile.pcmChannels pcm of
+          Right OpusFile.Stereo ->
+            OpenAL.Stereo16
+          Right OpusFile.Mono ->
+            OpenAL.Mono16
+          Left n ->
+            error $ "unexpected channels: " <> show n
+
+    OpenAL.bufferData buffer $= OpenAL.BufferData mreg alFormat 48000
+
+  source <- OpenAL.genObjectName
+  OpenAL.buffer source $= Just buffer
+  pure (OpusFile.pcmTime pcm, source)
+
+withAL :: IO () -> IO ()
+withAL action = do
+  OpenAL.openDevice Nothing >>= \case
+    Nothing ->
+      error  "boo. no device"
+    Just device -> do
+      OpenAL.createContext device [] >>= \case
+        Nothing ->
+          error "OpenAL.createContext failed"
+        Just ctx ->
+          OpenAL.currentContext $= Just ctx
+      () <- action
+      OpenAL.closeDevice device >>= print
diff --git a/opusfile.cabal b/opusfile.cabal
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--- /dev/null
+++ b/opusfile.cabal
@@ -0,0 +1,69 @@
+cabal-version: 1.12
+
+-- This file has been generated from package.yaml by hpack version 0.34.4.
+--
+-- see: https://github.com/sol/hpack
+--
+-- hash: c7063700f8e088ab3fbf8e386eba0e501f42d8f6332ae31aaa74b2084bea9b1f
+
+name:           opusfile
+version:        0.1.0.0
+synopsis:       FFI bindings for libopusfile
+category:       Sound
+author:         Alexander Bondarenko
+maintainer:     aenor.realm@gmail.com
+copyright:      Alexander Bondarenko
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+    ChangeLog.md
+
+source-repository head
+  type: git
+  location: https://gitlab.com/dpwiz/opusfile
+
+flag executables
+  manual: True
+  default: False
+
+library
+  exposed-modules:
+      Sound.OpusFile
+  other-modules:
+      Paths_opusfile
+  hs-source-dirs:
+      src
+  default-extensions:
+      BlockArguments
+      LambdaCase
+      TypeApplications
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wpartial-fields -Wredundant-constraints
+  extra-libraries:
+      opusfile
+  build-depends:
+      base >=4.7 && <5
+    , bytestring
+  default-language: Haskell2010
+
+executable example-openal
+  main-is: Main.hs
+  other-modules:
+      Paths_opusfile
+  hs-source-dirs:
+      examples/openal-playfile
+  default-extensions:
+      BlockArguments
+      LambdaCase
+      TypeApplications
+  ghc-options: -Wall -Wcompat -Widentities -Wincomplete-record-updates -Wincomplete-uni-patterns -Wpartial-fields -Wredundant-constraints -threaded -rtsopts -with-rtsopts=-maxN4
+  build-depends:
+      OpenAL
+    , StateVar
+    , base >=4.7 && <5
+    , bytestring
+    , opusfile
+  if !flag(executables)
+    buildable: False
+  default-language: Haskell2010
diff --git a/src/Sound/OpusFile.hs b/src/Sound/OpusFile.hs
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--- /dev/null
+++ b/src/Sound/OpusFile.hs
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+{-# LANGUAGE ForeignFunctionInterface #-}
+
+module Sound.OpusFile
+  ( Handle(..)
+  , OggOpusFile
+  , openMemoryBS
+  , openMemory
+  , free
+
+  , Channels(..)
+  , channelCount
+  , pcmTotal
+
+  , Pcm(..)
+  , decodeInt16
+  ) where
+
+import Data.ByteString (ByteString)
+import Data.ByteString.Unsafe (unsafeUseAsCStringLen)
+import Data.Int (Int16, Int64)
+import Foreign (ForeignPtr, Ptr)
+import Foreign.C.Types (CChar, CInt(..))
+import System.IO.Unsafe (unsafePerformIO)
+
+import qualified Foreign
+
+-- * Loading
+
+newtype Handle = Handle (Ptr OggOpusFile)
+  deriving (Eq, Show)
+
+data OggOpusFile
+
+openMemoryBS :: ByteString -> IO (Either Int Handle)
+openMemoryBS bs = unsafeUseAsCStringLen bs \(dataPtr, dataLen) ->
+  openMemory dataPtr (fromIntegral dataLen)
+
+openMemory :: Ptr CChar -> CInt -> IO (Either Int Handle)
+openMemory dataPtr dataLen =
+  Foreign.alloca \errorPtr -> do
+    oggOpusFile <- op_test_memory dataPtr dataLen errorPtr
+    Foreign.peek errorPtr >>= \case
+      0 -> do
+        op_test_open oggOpusFile >>= \case
+          0 ->
+            pure $ Right (Handle oggOpusFile)
+          err ->
+            pure $ Left (fromIntegral err)
+      err ->
+        pure $ Left (fromIntegral err)
+
+free :: Handle -> IO ()
+free (Handle handle) = op_free handle
+
+-- * Information
+
+data Channels
+  = Mono
+  | Stereo
+  deriving (Eq, Ord, Show, Enum, Bounded)
+
+channelCount :: Handle -> Either Int Channels
+channelCount (Handle handle) =
+  case unsafePerformIO (op_channel_count handle) of
+    1 -> Right Mono
+    2 -> Right Stereo
+    n -> Left (fromIntegral n)
+
+pcmTotal :: Handle -> Int
+pcmTotal (Handle handle) =
+  fromIntegral $ unsafePerformIO (op_pcm_total handle)
+
+-- * Decoding
+
+data Pcm a = Pcm
+  { pcmData     :: ForeignPtr a
+  , pcmSize     :: Int
+  , pcmTime     :: Double
+  , pcmChannels :: Either Int Channels
+  }
+  deriving (Eq, Show)
+
+decodeInt16 :: Handle -> IO (Pcm Int16)
+decodeInt16 h@(Handle handle) = do
+  fptr <- Foreign.mallocForeignPtrBytes byteSize
+  Foreign.withForeignPtr fptr (go 0) >>= \case
+    Left ret ->
+      error $ show ret
+    Right _samplesDone ->
+      pure Pcm
+        { pcmData     = fptr
+        , pcmSize     = byteSize
+        , pcmTime     = fromIntegral hPcmSize / 48000
+        , pcmChannels = hPcmChannels
+        }
+
+  where
+    hPcmChannels = channelCount h
+    hPcmSize = pcmTotal h
+
+    byteSize = hPcmSize * numChannels * sampleBytes
+    samples = hPcmSize * numChannels
+
+    numChannels = case hPcmChannels of
+      Right Mono   -> 1
+      Right Stereo -> 2
+      Left n       -> n
+
+    sampleBytes = Foreign.sizeOf (undefined :: Int16)
+
+    go samplesRead buf = do
+      ret <- op_read
+        handle
+        buf
+        (fromIntegral samples)
+        Foreign.nullPtr
+      if ret < 0 then
+        pure $ Left ret
+      else do
+        let samplesDone = samplesRead + fromIntegral ret
+        if samplesDone < hPcmSize then
+          go samplesDone $
+            Foreign.plusPtr buf (fromIntegral ret * numChannels * sampleBytes)
+        else
+          pure $ Right samplesDone
+
+-- * FFI
+
+foreign import ccall "op_free"
+  op_free :: Ptr OggOpusFile -> IO ()
+
+foreign import ccall "op_test_memory"
+  op_test_memory :: Ptr CChar -> CInt -> Ptr CInt -> IO (Ptr OggOpusFile)
+
+foreign import ccall "op_test_open"
+  op_test_open :: Ptr OggOpusFile -> IO CInt
+
+foreign import ccall "op_channel_count"
+  op_channel_count :: Ptr OggOpusFile -> IO CInt
+
+foreign import ccall "op_pcm_total"
+  op_pcm_total :: Ptr OggOpusFile -> IO Int64
+
+foreign import ccall "op_read"
+  op_read
+    :: Ptr OggOpusFile -- _of
+    -> Ptr Int16       -- _pcm
+    -> CInt            -- _buf_size
+    -> Ptr CInt        -- _li
+    -> IO CInt