2 files changed, 76 insertions, 33 deletions

diff --git a/video/mpegps_decoder.cpp b/video/mpegps_decoder.cpp
index af9e4f5bb0..e34053da73 100644
--- a/video/mpegps_decoder.cpp
+++ b/video/mpegps_decoder.cpp
@@ -553,11 +553,14 @@ MPEGPSDecoder::AC3AudioTrack::AC3AudioTrack(Common::SeekableReadStream *firstPac
 	initStream(firstPacket);
 	if (_sampleRate >= 0) {
 		_audStream = Audio::makeQueuingAudioStream(_sampleRate, true);
-		decodeAC3Data(firstPacket);
 	} else {
 		_audStream = 0;
 		firstPacket->seek(0);
 	}
+
+	_inBufPtr = _inBuf;
+	_flags = 0;
+	_frameSize = 0;
 }
 
 MPEGPSDecoder::AC3AudioTrack::~AC3AudioTrack() {
@@ -567,7 +570,6 @@ MPEGPSDecoder::AC3AudioTrack::~AC3AudioTrack() {
 
 bool MPEGPSDecoder::AC3AudioTrack::sendPacket(Common::SeekableReadStream *packet, uint32 pts, uint32 dts) {
 	if (_audStream) {
-		initStream(packet);
 		decodeAC3Data(packet);
 	}
 	delete packet;
@@ -591,47 +593,85 @@ void MPEGPSDecoder::AC3AudioTrack::initStream(Common::SeekableReadStream *packet
 		packet->seek(i, SEEK_SET);
 		packet->read(buf, sizeof(buf));
 
-		_packetLength = a52_syncinfo(buf, &flags, &_sampleRate, &bitRate);
+		int packetLength = a52_syncinfo(buf, &flags, &_sampleRate, &bitRate);
 
-		if (_packetLength > 0) {
+		if (packetLength > 0) {
 			break;
 		}
 	}
 }
 
+enum {
+	HEADER_SIZE = 7
+};
+
 void MPEGPSDecoder::AC3AudioTrack::decodeAC3Data(Common::SeekableReadStream *packet) {
-	// This doesn't work since _packetLength is often longer than the,
-	// stream, which may go a long way towards explaining all the Valgrind
-	// errors I'm getting. Not to mention that the output sounds nothing
-	// at all like what I want.
-	byte *buf = new byte[_packetLength];
-	packet->read(buf, _packetLength);
-
-	int flags = A52_STEREO | A52_ADJUST_LEVEL;
-	sample_t level = 32767;
-	int bias = 0;
-
-	if (a52_frame(_a52State, buf, &flags, &level, bias) == 0) {
-		int16 *outputBuffer = (int16 *)malloc(6 * 512 * sizeof(int16));
-		int16 *outputPtr = outputBuffer;
-		int outputLength = 0;
-		for (int i = 0; i < 6; i++) {
-			if (a52_block(_a52State)) {
-				sample_t *samples = a52_samples(_a52State);
-				for (int j = 0; j < 256; j++) {
-					outputPtr[j * 2] = (int16)samples[j];
-					outputPtr[j * 2 + 1] = (int16)samples[256 + j];
+	while (packet->pos() < packet->size()) {
+		uint32 leftSize = packet->size() - packet->pos();
+		uint32 len = _inBufPtr - _inBuf;
+		if (_frameSize == 0) {
+			// No header seen: find one
+			len = HEADER_SIZE - len;
+			if (len > leftSize)
+				len = leftSize;
+			packet->read(_inBufPtr, len);
+			leftSize -= len;
+			_inBufPtr += len;
+			if ((_inBufPtr - _inBuf) == HEADER_SIZE) {
+				int sampleRate, bitRate;
+				len = a52_syncinfo(_inBuf, &_flags, &sampleRate, &bitRate);
+				if (len == 0) {
+					memmove(_inBuf, _inBuf + 1, HEADER_SIZE - 1);
+					_inBufPtr--;
+				} else {
+					_frameSize = len;
 				}
-				outputPtr += 512;
-				outputLength += 1024;
 			}
-		}
-		if (outputLength > 0) {
-			_audStream->queueBuffer((byte *)outputBuffer, outputLength, DisposeAfterUse::YES, Audio::FLAG_STEREO);
+		} else if (len < _frameSize) {
+			len = _frameSize - len;
+			if (len > leftSize)
+				len = leftSize;
+
+			assert(len < sizeof(_inBuf) - (_inBufPtr - _inBuf));
+			packet->read(_inBufPtr, len);
+			leftSize -= len;
+			_inBufPtr += len;
+		} else {
+			int flags = A52_STEREO | A52_ADJUST_LEVEL;
+			sample_t level = 32767;
+
+			if (a52_frame(_a52State, _inBuf, &flags, &level, 0) != 0)
+				error("Frame fail");
+
+			int16 *outputBuffer = (int16 *)malloc(6 * 256 * 2 * 2);
+			int16 *outputPtr = outputBuffer;
+			int outputLength = 0;
+			for (int i = 0; i < 6; i++) {
+				if (a52_block(_a52State) == 0) {
+					sample_t *samples = a52_samples(_a52State);
+					for (int j = 0; j < 256; j++) {
+						*outputPtr++ = (int16)samples[j];
+						*outputPtr++ = (int16)samples[j + 256];
+					}
+
+					outputLength += 1024;
+				}
+			}
+
+			if (outputLength > 0) {
+				flags = Audio::FLAG_STEREO | Audio::FLAG_16BITS;
+
+#ifdef SCUMM_LITTLE_ENDIAN
+				flags |= Audio::FLAG_LITTLE_ENDIAN;
+#endif
+
+				_audStream->queueBuffer((byte *)outputBuffer, outputLength, DisposeAfterUse::YES, flags);
+			}
+
+			_inBufPtr = _inBuf;
+			_frameSize = 0;
 		}
 	}
-
-	delete[] buf;
 }
 
 #endif
diff --git a/video/mpegps_decoder.h b/video/mpegps_decoder.h
index 39b3a47af9..bf9c28e952 100644
--- a/video/mpegps_decoder.h
+++ b/video/mpegps_decoder.h
@@ -148,8 +148,11 @@ private:
 	private:
 		Audio::QueuingAudioStream *_audStream;
 		a52_state_t *_a52State;
+		uint32 _frameSize;
+		byte _inBuf[4096];
+		byte *_inBufPtr;
+		int _flags;
 		int _sampleRate;
-		int _packetLength;
 
 		void initStream(Common::SeekableReadStream *packet);
 		void decodeAC3Data(Common::SeekableReadStream *packet);