Hi there! I've taken my first stab at writing some (admittedly minimal) libraries for Haskell, and would love to get feedback on them: * hmad: a wrapper for the libmad MP3 decoder. http://maubi.net/~waterson/REPO/hmad * CoreAudio: a wrapper for OS/X CoreAudio. http://maubi.net/~waterson/REPO/CoreAudio (You should be able to "darcs get" the above links, if you want.) I wrote the libmad wrapper to generate a "stream" (i.e., a lazy list) of audio samples. CoreAudio allows the input stream to be lazy, as well. So, here's a simple MP3 player:
module Main where
import Sound.CoreAudio import Codec.Audio.MP3.Mad import qualified Data.ByteString.Lazy as B import System import System.IO
main :: IO () main = do files <- getArgs mapM_ playFile files
playFile :: String -> IO () playFile file = withBinaryFile file ReadMode $ \ inHandle -> do xs <- B.hGetContents inHandle samples <- decode xs play samples
I do have a couple questions... * The CoreAudio library requires its users to be compiled with "-threaded". Is there a way to specify that in the Cabal file? * I wanted to be able to generate a variety of streams from libmad. Besides stereo linear PCM data, it also seemed like it might be worth-while to produce a stream of MP3 frame headers, the unsynthesized frequency domain data, and so on. I tried to accomplish this with a the DecoderSink class, but I'm not sure I succeeded. Any thoughts here would be appreciated! I hope someone else finds these useful. The FFI was a joy to use once I figured it out... :) chris