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sdlAudioPlayer.lua
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sdlAudioPlayer.lua
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local ffi = require"ffi"
local sdl = require"sdl2_ffi"
local sndf = require"sndfile_ffi"
--------------will run in a same thread and different lua state and return the callback
local function AudioInit(audioplayer,audioplayercdef,postfunc,postdata,postcode)
local ffi = require"ffi"
local sdl = require"sdl2_ffi"
local sndf = require"sndfile_ffi"
ffi.cdef(audioplayercdef)
audioplayer = ffi.cast("audioplayer*",audioplayer)
local root = audioplayer.root
local spec
local typebuffer,lenfac,nchannels
local timefac
local bufpointer
local readfunc,writefunc
local postfuncS
--wait until device is opened to define locals declared above
local function setspecs()
spec = audioplayer.obtained_spec[0]
--print("spec.format", spec.format, spec.channels)
typebuffer,lenfac,nchannels = sdl.audio_buffer_type(spec)
timefac = 1/spec.freq
bufpointer = typebuffer.."*"
readfunc = "readf_"..typebuffer
writefunc = "writef_"..typebuffer
postfuncS = postfunc(postdata,postcode,typebuffer,nchannels,spec)
end
local floor = math.floor
-- this is the real callback
return function(ud,stream,len)
if not spec then setspecs() end
local streamTime = audioplayer.streamTime
local lenf = len*lenfac
assert(lenf == floor(lenf))
local windowsize = lenf * timefac
sdl.memset(stream, 0, len)
local streamf = ffi.cast(bufpointer,stream)
ffi.fill(stream,len)
local readbuffer = ffi.new(typebuffer.."[?]",lenf*nchannels)
local sf_node = root
while true do
if sf_node.next~=nil then
sf_node = sf_node.next[0]
local sf = sf_node.sf
if sf.resampler~=nil then
sf = sf.resampler
end
if sf_node.timeoffset <= streamTime then --already setted
local readen = tonumber(sf[readfunc](sf,readbuffer,lenf))
for i=0,(readen*nchannels)-1 do
streamf[i] = streamf[i] + readbuffer[i]*sf_node.level
end
elseif sf_node.timeoffset < streamTime + windowsize then --set it here
--print"sett--------------------------------"
local frames = floor((streamTime + windowsize - sf_node.timeoffset) * spec.freq)
local res = sf:seek( 0, sndf.SEEK_SET)
local readen = tonumber(sf[readfunc](sf,readbuffer,frames))
local j=0
for i=(lenf - frames)*nchannels,((readen+lenf-frames)*nchannels)-1 do
--for i=(lenf - frames)*nchannels,((lenf)*nchannels)-1 do
streamf[i] = streamf[i] + readbuffer[j]*sf_node.level
j = j + 1
end
end
else break end
end
postfuncS(streamf,lenf,streamTime)
if audioplayer.recordfile~= nil then
audioplayer.recordfile[writefunc](audioplayer.recordfile,streamf,lenf)
end
audioplayer.streamTime = streamTime + lenf*timefac
end
end
---------------------------------------------------
---------------------------------------------audioplayer interface
local audioplayercdef = [[
typedef struct sf_node sf_node;
struct sf_node
{
SNDFILE_ref *sf;
double level;
double timeoffset;
sf_node *next;
} sf_node;
typedef struct audioplayer
{
SDL_AudioSpec wanted_spec[1];
SDL_AudioSpec obtained_spec[1];
sf_node root;
SNDFILE_ref *recordfile;
double streamTime;
SDL_AudioDeviceID device;
src_callback_t resampler_input_cb;
} audioplayer;
]]
ffi.cdef(audioplayercdef)
local ap_resampler_input_cb
local ancla_nodes = {}
local ancla_resam = {}
local AudioPlayer_mt = {}
AudioPlayer_mt.__index = AudioPlayer_mt
function AudioPlayer_mt:__new(t,postfunc,postdata,postcode)
local postfunc = postfunc or function() return function() end end
local ap = ffi.new("audioplayer")
assert(ap.root.next == nil)
local spec = ap.wanted_spec[0]
spec.freq = t.freq or 44100
spec.format = t.format or 0
spec.channels = t.channels or 2
spec.samples = t.samples or 0
local callback, cbmaker = sdl.MakeAudioCallback(AudioInit,ap,audioplayercdef,postfunc,postdata,postcode)
spec.callback = callback
ap_resampler_input_cb = cbmaker:additional_cb(function()
local sndf = require"sndfile_ffi"
return sndf.resampler_input_cb
end,"long (*) (void *cb_data, float **data)")--"src_callback_t")
ap.resampler_input_cb = ap_resampler_input_cb
ap.device = sdl.OpenAudioDevice(t.device, sdl.FALSE, ap.wanted_spec, ap.obtained_spec,sdl.AUDIO_ALLOW_FORMAT_CHANGE);
if ap.device == 0 then
local err = sdl.GetError()
return nil, err~=nil and ffi.string(err) or "unknown error opening device"
end
ffi.gc(ap,self.close)
return ap
end
function AudioPlayer_mt:close()
ffi.gc(self,nil)
for node in self:nodes() do
node.sf:close()
end
if self.recordfile ~=nil then
self.recordfile:close()
end
sdl.CloseAudioDevice(self.device);
end
function AudioPlayer_mt:get_stream_time()
self:lock()
local ret = self.streamTime
self:unlock()
return ret
end
function AudioPlayer_mt:set_stream_time(time)
self:lock()
self.streamTime = time
local sf_node = self.root
while true do
sf_node = sf_node.next[0]
if sf_node == nil then break end
local sf = sf_node.sf
if sf.resampler~=nil then
sf = sf.resampler
end
if sf_node.timeoffset <= time then
local frames = math.floor((time - sf_node.timeoffset) * sf_node.sf:samplerate())
local res = sf:seek( frames, sndf.SEEK_SET) ;
end
end
self:unlock()
end
function AudioPlayer_mt:lock()
sdl.LockAudioDevice(self.device)
end
function AudioPlayer_mt:unlock()
sdl.UnlockAudioDevice(self.device)
end
function AudioPlayer_mt:start()
--sdl.LockAudio()
sdl.PauseAudioDevice(self.device, 0)
--sdl.UnlockAudio()
end
function AudioPlayer_mt:stop()
--sdl.LockAudio()
sdl.PauseAudioDevice(self.device, 1)
--sdl.UnlockAudio()
end
function AudioPlayer_mt:insert(filename,level,timeoffset)
level = level or 1
timeoffset = timeoffset or 0
local sf = sndf.Sndfile(filename)
--check channels and samplerate
if sf:channels() ~= self.obtained_spec[0].channels then
print(filename,"has wrong number of channels",sf:channels())
sf:close()
return nil
end
local selfkey = tostring(self)
if sf:samplerate() ~= self.obtained_spec[0].freq then
local resamp = sf:resampler_create(nil, nil,ap_resampler_input_cb)
resamp:set_ratio(self.obtained_spec[0].freq/sf:samplerate())
local anchor = ancla_resam[selfkey] or {}
ancla_resam[selfkey] = anchor
table.insert(anchor,resamp)
end
local node = ffi.new"sf_node[1]"
local anchor = ancla_nodes[selfkey] or {}
ancla_nodes[selfkey] = anchor
table.insert(anchor,node)
node[0].sf = sf
node[0].level = level
node[0].timeoffset = timeoffset
node[0].next = self.root.next
self:lock()
self.root.next = node
self:unlock()
return node[0]
end
local recordfile_anchor
function AudioPlayer_mt:record(filename,format)
assert(self.recordfile==nil,"AudioPlayer already has recording file.")
local sf = sndf.Sndfile(filename,"w",self.obtained_spec[0].freq,self.obtained_spec[0].channels,format)
recordfile_anchor = sf
self.recordfile = sf
return sf
end
function AudioPlayer_mt:erase(node)
self:lock()
local sf_node = self.root
local anchor = ancla_nodes[tostring(self)]
assert(anchor)
while true do
local prev = sf_node
sf_node = sf_node.next[0]
if sf_node == nil then break end
if sf_node == node then
--remove from ancla_nodes
for i,nodeptr in ipairs(anchor) do
if nodeptr[0]==node then
table.remove(anchor,i)
break
end
end
prev.next = sf_node.next
node.sf:close()
break
end
end
self:unlock()
end
function AudioPlayer_mt:nodes()
local cur_node = self.root
return function()
local nextnode = cur_node.next[0]
if nextnode == nil then return nil end
cur_node = nextnode
return nextnode
end
end
local AudioPlayer = ffi.metatype("audioplayer",AudioPlayer_mt)
return AudioPlayer