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/*
* Worldvisions Weaver Software:
* Copyright (C) 1997-2002 Net Integration Technologies, Inc.
*
* Provides a WvEncoder abstraction for the SimpleAudio audio packet format.
* suitable for encoding voice at low bitrates.
*
* Only monaural audio is supported for now.
*/
#include "wvaudioencoder.h"
#include "wvpcmutils.h"
/***** WvSimpleAudioEncoder *****/
WvSimpleAudioEncoder::WvSimpleAudioEncoder(unsigned int channels,
unsigned int samplerate) :
_channels(channels), _samplesperframe(samplerate / 1000 * 20)
{
}
bool WvSimpleAudioEncoder::_typedencode(IBuffer &inbuf, OBuffer &outbuf,
bool flush)
{
static WvPCMUnnormFloatToSigned16Functor f;
for (;;)
{
// find how much data is available
size_t count = inbuf.used();
if (count == 0) return true;
if (count < _samplesperframe)
return ! flush; // not enough data
// convert this frame
while (count > 0)
{
size_t avail = outbuf.optallocable();
if (avail == 0) return false;
if (avail > count) avail = count;
count -= avail;
const IType *indata = inbuf.get(avail);
OType *outdata = outbuf.alloc(avail);
while (avail-- > 0)
*(outdata++) = f(*(indata++));
}
// return if we're not flushing
if (! flush)
return true;
}
}
bool WvSimpleAudioEncoder::_typedfinish(OBuffer &outbuf)
{
return true;
}
/***** WvSimpleAudioDecoder *****/
WvSimpleAudioDecoder::WvSimpleAudioDecoder(unsigned int channels,
unsigned int samplerate) :
_channels(channels), _samplesperframe(samplerate / 1000 * 20)
{
}
bool WvSimpleAudioDecoder::_typedencode(IBuffer &inbuf, OBuffer &outbuf,
bool flush)
{
static WvPCMSigned16ToUnnormFloatFunctor f;
for (;;)
{
size_t avail = inbuf.used();
if (avail == 0) return true;
if (outbuf.free() < _samplesperframe)
return false; // not enough room
size_t skip = 0;
if (avail > _samplesperframe)
{
// packet is too large but try to decode some audio anyhow
skip = avail - _samplesperframe;
avail -= skip;
}
const IType *indata = inbuf.get(avail);
inbuf.skip(skip); // skip over bad data
OType *outdata = outbuf.alloc(_samplesperframe);
while (avail-- > 0)
*(outdata++) = f(*(indata++));
if (! flush)
return true;
}
}
bool WvSimpleAudioDecoder::_typedfinish(OBuffer &outbuf)
{
return true;
}
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