SndfileStream() supports raw files now, by passing through samplerate, channels and libsndfile format

2 files changed, 23 insertions, 4 deletions

diff --git a/applause.lua b/applause.lua
index e257fb2..1a67ed7 100644
--- a/applause.lua
+++ b/applause.lua
@@ -303,6 +303,17 @@ function Stream:scale(v1, v2)
 	end)
 end
 
+-- same as Stream:scale() but for values between [0, 127]
+-- (ie. MIDI CC values)
+function Stream:ccscale(v1, v2)
+	local lower = v2 and v1 or 0
+	local upper = v2 or v1
+
+	return self:map(function(x)
+		return (x/127)*(upper - lower) + lower
+	end)
+end
+
 function Stream:scan(fnc)
 	return ScanStream:new(self, fnc)
 end
@@ -943,12 +954,17 @@ end
 
 SndfileStream = DeriveClass(Stream)
 
-function SndfileStream:ctor(filename)
+function SndfileStream:ctor(filename, samplerate, channels, format)
 	-- FIXME: This fails if the file is not at the
 	-- correct sample rate. Need to resample...
-	local handle = sndfile:new(filename, "SFM_READ")
+	-- NOTE: samplerate and channels are ignored unless SF_FORMAT_RAW
+	-- files are read.
+	local handle = sndfile:new(filename, "SFM_READ",
+	                           samplerate, channels, format)
 	self.filename = filename
+	self.samplerate = handle.info.samplerate
 	self.channels = handle.info.channels
+	self.format = handle.info.format
 	self.frames = tonumber(handle.info.frames)
 	handle:close()
 
@@ -969,7 +985,8 @@ function SndfileStream:gtick()
 	-- read pointer which is important when reusing the stream.
 	-- NOTE: We could do this with a single handle per object but
 	-- by maintaining our own read position and seeking before reading.
-	local handle = sndfile:new(self.filename, "SFM_READ")
+	local handle = sndfile:new(self.filename, "SFM_READ",
+	                           self.samplerate, self.channels, self.format)
 
 	-- Make sure that we are still reading the same file;
 	-- at least with the same meta-data.
diff --git a/sndfile.lua b/sndfile.lua
index e91fb70..13c952d 100644
--- a/sndfile.lua
+++ b/sndfile.lua
@@ -1,6 +1,7 @@
 -- module table
 local sndfile = {}
 
+local bit = require "bit"
 local ffi = require "ffi"
 
 ffi.cdef[[
@@ -165,7 +166,8 @@ function sndfile:new(path, mode, samplerate, channels, format)
 
 	local info = ffi.new("SF_INFO[1]")
 
-	if mode ~= "SFM_READ" then
+	if mode == "SFM_WRITE" or
+	   (format and bit.band(format, ffi.C.SF_FORMAT_TYPEMASK) == ffi.C.SF_FORMAT_RAW) then
 		info[0].samplerate = samplerate or 44100
 		info[0].channels = channels or 1
 		info[0].format = format or sndfile.guess_format(path)