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List:       kde-multimedia
Subject:    [PATCH] resampler underrun check
From:       Stefan Westerfeld <stefan () space ! twc ! de>
Date:       2000-09-11 9:36:10
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Hi!

When an external stream disconnects (i.e. artsdsp/artscat/C API), aRts should
still play all the packets that have been sent so far and not immediately
drop playing the sound. To do so, it queries ByteStreamToAudio::running() to
see if there is still work to do.

However, the ByteStreamToAudio::running() method is currently always returning
false, which isn't optimal for this kind of thing ;).

So here is a patch that fixes this, I'll apply it tomorrow if there are no
objections.

   Cu... Stefan
-- 
  -* Stefan Westerfeld, stefan@space.twc.de (PGP!), Hamburg/Germany
     KDE Developer, project infos at http://space.twc.de/~stefan/kde *-         

["20000911-resampler-underrun-addition.diff" (text/plain)]

Index: resample.cc
===================================================================
RCS file: /home/kde/kdelibs/arts/flow/resample.cc,v
retrieving revision 1.1
diff -b -u -p -r1.1 resample.cc
--- resample.cc	2000/09/06 12:39:15	1.1
+++ resample.cc	2000/09/11 09:32:09
@@ -37,14 +37,26 @@
 
 using namespace Arts;
 
+class Arts::ResamplerPrivate {
+public:
+	bool underrun;	
+};
+
 Resampler::Resampler(Refiller *refiller) :
 	dropBytes(0), refiller(refiller), pos(0.0), step(1.0), channels(2),
 	bits(16),
 	block(0), haveBlock(-1)
 {
+	d = new ResamplerPrivate();
+	d->underrun = false;
 	updateSampleSize();
 }
 
+Resampler::~Resampler()
+{
+	delete d;
+}
+
 void Resampler::updateSampleSize()
 {
 	sampleSize = channels * bits / 8;
@@ -68,6 +80,11 @@ void Resampler::setBits(int newBits)
 	updateSampleSize();
 }
 
+bool Resampler::underrun()
+{
+	return d->underrun;
+}
+
 void Resampler::ensureRefill()
 {
 	if(haveBlock == block) return;
@@ -77,6 +94,8 @@ void Resampler::ensureRefill()
 	{
 		missing = bufferSize+sampleSize
 				- refiller->read(buffer,bufferSize+sampleSize);
+
+		d->underrun = (missing == bufferSize+sampleSize);
 	}
 	else
 	{
@@ -93,8 +112,14 @@ void Resampler::ensureRefill()
 		{
 			missing = bufferSize
 					- refiller->read(&buffer[sampleSize], bufferSize);
+
+			d->underrun = (missing == bufferSize);
+		}
+		else
+		{
+			missing = bufferSize;
+			d->underrun = true;
 		}
-		else missing = bufferSize;
 	}
 	haveBlock++;
 	assert(haveBlock == block);
Index: resample.h
===================================================================
RCS file: /home/kde/kdelibs/arts/flow/resample.h,v
retrieving revision 1.1
diff -b -u -p -r1.1 resample.h
--- resample.h	2000/09/06 12:39:15	1.1
+++ resample.h	2000/09/11 09:32:09
@@ -32,6 +32,8 @@ public:
 	virtual ~Refiller();
 };
 
+class ResamplerPrivate;
+
 class Resampler {
 protected:
 	static const unsigned int bufferSize = 256;		//  64 samples in buffer
@@ -55,10 +57,14 @@ protected:
 	void ensureRefill();
 public:
 	Resampler(Refiller *refiller);
+	~Resampler();
+
 	void setStep(double step);
 	void setChannels(int channels);
 	void setBits(int bits);
 	void run(float *left, float *right, unsigned long samples);
+
+	bool underrun();
 };
 
 };
Index: convert.cc
===================================================================
RCS file: /home/kde/kdelibs/arts/flow/convert.cc,v
retrieving revision 1.8
diff -b -u -p -r1.8 convert.cc
--- convert.cc	2000/08/24 16:13:48	1.8
+++ convert.cc	2000/09/11 09:32:11
@@ -267,3 +267,17 @@ unsigned long uni_convert_stereo_2float(
 	}
 	return doSamples;
 }
+
+// undefine all that stuff (due to --enable-final)
+#undef compose_16le
+#undef conv_16le_float
+#undef convert_16le_float
+#undef conv_8_float
+#undef convert_8_float
+#undef datatype_16le
+#undef datasize_16le
+#undef datatype_8
+#undef datasize_8
+#undef datatype_float
+#undef datasize_float
+#undef mk_converter
Index: bytestreamtoaudio_impl.cc
===================================================================
RCS file: /home/kde/kdelibs/arts/flow/bytestreamtoaudio_impl.cc,v
retrieving revision 1.8
diff -b -u -p -r1.8 bytestreamtoaudio_impl.cc
--- bytestreamtoaudio_impl.cc	2000/09/06 12:39:15	1.8
+++ bytestreamtoaudio_impl.cc	2000/09/11 09:32:11
@@ -30,10 +30,11 @@ using namespace Arts;
 
 
 class PacketRefiller : public Refiller {
-public:
+protected:
 	queue< DataPacket<mcopbyte>* > inqueue;
 	int pos;
 
+public:
 	PacketRefiller() : pos(0)
 	{
 	}
@@ -73,10 +74,9 @@ class ByteStreamToAudio_impl : public By
 	PacketRefiller refiller;
 	Resampler resampler;
 	long _samplingRate, _channels, _bits;
-	bool _running;
 public:
 	ByteStreamToAudio_impl() :resampler(&refiller),
-			_samplingRate(44100), _channels(2), _bits(16), _running(false)
+			_samplingRate(44100), _channels(2), _bits(16)
 	{
 		//
 	}
@@ -99,7 +99,7 @@ public:
 		resampler.setBits(_bits);
 	}
 
-	bool running() { return _running; }
+	bool running() { return !resampler.underrun(); }
 
 	void process_indata(DataPacket<mcopbyte> *packet)
 	{

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