@@ -3,13 +3,13 @@ Features:
  - Support for gamepad axes, e.g. analog sticks or triggers
  - Add scale presets for up to 6x
  - Debugger: Add CLI "frame", frame advance command
- - Better audio resampling via FFmpeg
  - Settings window
  - Bilinear resampling option
  - Add option to skip BIOS start screen
  - List of recently opened games
  - Support for games using the Solar Sensor
  - Debugger: Add CLI functions for writing to memory
+ - Better audio resampling via blip-buf
 Bugfixes:
  - Qt: Fix issue with set frame sizes being the wrong height
  - Qt: Fix emulator crashing when full screen if a game is not running

@@ -8,6 +8,7 @@ set(USE_FFMPEG ON CACHE BOOL "Whether or not to enable FFmpeg support")
 set(USE_PNG ON CACHE BOOL "Whether or not to enable PNG support")
 set(USE_LIBZIP ON CACHE BOOL "Whether or not to enable ZIP support")
 set(USE_MAGICK ON CACHE BOOL "Whether or not to enable ImageMagick support")
+set(USE_BLIP ON CACHE BOOL "Whether or not to enable blip_buf support")
 set(BUILD_QT ON CACHE BOOL "Build Qt frontend")
 set(BUILD_SDL ON CACHE BOOL "Build SDL frontend")
 set(BUILD_PERF OFF CACHE BOOL "Build performance profiling tool")
@@ -156,7 +157,6 @@ endif()
 	include_directories(AFTER ${LIBAVCODEC_INCLUDE_DIRS} ${LIBAVFORMAT_INCLUDE_DIRS} ${LIBAVRESAMPLE_INCLUDE_DIRS} ${LIBAVUTIL_INCLUDE_DIRS} ${LIBSWSCALE_INCLUDE_DIRS})
 	link_directories(${LIBAVCODEC_LIBRARY_DIRS} ${LIBAVFORMAT_LIBRARY_DIRS} ${LIBAVRESAMPLE_LIBRARY_DIRS} ${LIBAVUTIL_LIBRARY_DIRS} ${LIBSWSCALE_LIBRARY_DIRS})
 	list(APPEND UTIL_SRC "${CMAKE_SOURCE_DIR}/src/platform/ffmpeg/ffmpeg-encoder.c")
-	list(APPEND UTIL_SRC "${CMAKE_SOURCE_DIR}/src/platform/ffmpeg/ffmpeg-resample.c")
 	string(REGEX MATCH "^[0-9]+" LIBAVCODEC_VERSION_MAJOR ${libavcodec_VERSION})
 	string(REGEX MATCH "^[0-9]+" LIBAVFORMAT_VERSION_MAJOR ${libavformat_VERSION})
 	string(REGEX MATCH "^[0-9]+" LIBAVRESAMPLE_VERSION_MAJOR ${libavresample_VERSION})
@@ -165,6 +165,13 @@ string(REGEX MATCH "^[0-9]+" LIBSWSCALE_VERSION_MAJOR ${libswscale_VERSION})
 	list(APPEND DEPENDENCY_LIB ${LIBAVCODEC_LIBRARIES} ${LIBAVFORMAT_LIBRARIES} ${LIBAVRESAMPLE_LIBRARIES} ${LIBAVUTIL_LIBRARIES} ${LIBSWSCALE_LIBRARIES})
 	set(CPACK_DEBIAN_PACKAGE_DEPENDS "${CPACK_DEBIAN_PACKAGE_DEPENDS},libavcodec${LIBAVCODEC_VERSION_MAJOR},libavformat${LIBAVFORMAT_VERSION_MAJOR},libavresample${LIBAVRESAMPLE_VERSION_MAJOR},libavutil${LIBAVUTIL_VERSION_MAJOR},libswscale${LIBSWSCALE_VERSION_MAJOR}")
 	set(CPACK_DEBIAN_PACKAGE_RECOMMENDS "libavcodec-extra")
+endif()
+
+if(USE_BLIP)
+	list(APPEND UTIL_SRC "${CMAKE_SOURCE_DIR}/src/third-party/blip_buf/blip_buf.c")
+	add_definitions(-DRESAMPLE_LIBRARY=RESAMPLE_BLIP_BUF)
+else()
+	add_definitions(-DRESAMPLE_LIBRARY=RESAMPLE_NN)
 endif()
 
 if(USE_MAGICK)
@@ -256,7 +263,7 @@ message(STATUS "	Video recording: ${USE_FFMPEG}")
 message(STATUS "	GIF recording: ${USE_MAGICK}")
 message(STATUS "	Screenshot/advanced savestate support: ${USE_PNG}")
 message(STATUS "	ZIP support: ${USE_LIBZIP}")
-message(STATUS "	Better audio resampling: ${USE_FFMPEG}")
+message(STATUS "	Better audio resampling: ${USE_BLIP}")
 message(STATUS "Frontend summary:")
 message(STATUS "	Qt: ${BUILD_QT}")
 message(STATUS "	SDL (${SDL_VERSION}): ${BUILD_SDL}")

@@ -114,4 +114,4 @@ ---------
 
 mGBA is Copyright © 2013 – 2014 Jeffrey Pfau. It is distributed under the [Mozilla Public License version 2.0](https://www.mozilla.org/MPL/2.0/). A copy of the license is available in the distributed LICENSE file.
 
-mGBA contains [inih](https://code.google.com/p/inih/), which is copyright © 2009 Brush Technology and used under a BSD 3-clause license.
+mGBA contains [inih](https://code.google.com/p/inih/), which is copyright © 2009 Brush Technology and used under a BSD 3-clause license; and [blip-buf](https://code.google.com/p/blip-buf/), which is copyright © 2003 – 2009 Shay Green and used under a Lesser GNU Public License.

@@ -12,6 +12,7 @@ #include "gba-thread.h"
 #include "gba-video.h"
 
 const unsigned GBA_AUDIO_SAMPLES = 2048;
+const unsigned BLIP_BUFFER_SIZE = 0x4000;
 const unsigned GBA_AUDIO_FIFO_SIZE = 8 * sizeof(int32_t);
 #define SWEEP_CYCLES (GBA_ARM7TDMI_FREQUENCY / 128)
 
@@ -27,8 +28,17 @@ static int _applyBias(struct GBAAudio* audio, int sample);
 static void _sample(struct GBAAudio* audio);
 
 void GBAAudioInit(struct GBAAudio* audio, size_t samples) {
+	audio->samples = samples;
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	CircleBufferInit(&audio->left, samples * sizeof(int16_t));
 	CircleBufferInit(&audio->right, samples * sizeof(int16_t));
+#else
+	audio->left = blip_new(BLIP_BUFFER_SIZE);
+	audio->right = blip_new(BLIP_BUFFER_SIZE);
+	// Guess too large; we hang producing extra samples if we guess too low
+	blip_set_rates(audio->left,  GBA_ARM7TDMI_FREQUENCY, 96000);
+	blip_set_rates(audio->right, GBA_ARM7TDMI_FREQUENCY, 96000);
+#endif
 	CircleBufferInit(&audio->chA.fifo, GBA_AUDIO_FIFO_SIZE);
 	CircleBufferInit(&audio->chB.fifo, GBA_AUDIO_FIFO_SIZE);
 }
@@ -77,21 +87,34 @@ audio->playingCh4 = false;
 	audio->enable = false;
 	audio->sampleInterval = GBA_ARM7TDMI_FREQUENCY / audio->sampleRate;
 
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	CircleBufferClear(&audio->left);
 	CircleBufferClear(&audio->right);
+#else
+	blip_clear(audio->left);
+	blip_clear(audio->right);
+	audio->clock = 0;
+#endif
 	CircleBufferClear(&audio->chA.fifo);
 	CircleBufferClear(&audio->chB.fifo);
 }
 
 void GBAAudioDeinit(struct GBAAudio* audio) {
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	CircleBufferDeinit(&audio->left);
 	CircleBufferDeinit(&audio->right);
+#else
+	blip_delete(audio->left);
+	blip_delete(audio->right);
+#endif
 	CircleBufferDeinit(&audio->chA.fifo);
 	CircleBufferDeinit(&audio->chB.fifo);
 }
 
 void GBAAudioResizeBuffer(struct GBAAudio* audio, size_t samples) {
 	GBASyncLockAudio(audio->p->sync);
+	audio->samples = samples;
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	size_t oldCapacity = audio->left.capacity;
 	int16_t* buffer = malloc(oldCapacity);
 	int16_t dummy;
@@ -119,6 +142,11 @@ }
 	}
 
 	free(buffer);
+#else
+	blip_clear(audio->left);
+	blip_clear(audio->right);
+	audio->clock = 0;
+#endif
 
 	GBASyncConsumeAudio(audio->p->sync);
 }
@@ -424,6 +452,13 @@ }
 
 void GBAAudioWriteSOUNDBIAS(struct GBAAudio* audio, uint16_t value) {
 	audio->soundbias = value;
+#if RESAMPLE_LIBRARY == RESAMPLE_BLIP_BUF
+	unsigned newSampleRate = 0x8000 << GBARegisterSOUNDBIASGetResolution(audio->soundbias);
+	if (audio->sampleRate != newSampleRate) {
+		audio->sampleRate = newSampleRate;
+		audio->sampleInterval = GBA_ARM7TDMI_FREQUENCY / audio->sampleRate;
+	}
+#endif
 }
 
 void GBAAudioWriteWaveRAM(struct GBAAudio* audio, int address, uint32_t value) {
@@ -495,6 +530,7 @@ }
 	CircleBufferRead8(&channel->fifo, &channel->sample);
 }
 
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 unsigned GBAAudioCopy(struct GBAAudio* audio, void* left, void* right, unsigned nSamples) {
 	GBASyncLockAudio(audio->p->sync);
 	unsigned read = 0;
@@ -553,6 +589,7 @@ }
 	}
 	return totalRead;
 }
+#endif
 
 bool _writeEnvelope(struct GBAAudioEnvelope* envelope, uint16_t value) {
 	envelope->length = GBAAudioRegisterEnvelopeGetLength(value);
@@ -771,14 +808,32 @@ sampleLeft = _applyBias(audio, sampleLeft);
 	sampleRight = _applyBias(audio, sampleRight);
 
 	GBASyncLockAudio(audio->p->sync);
+	unsigned produced;
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	CircleBufferWrite16(&audio->left, sampleLeft);
 	CircleBufferWrite16(&audio->right, sampleRight);
-	unsigned produced = CircleBufferSize(&audio->left);
+	produced = CircleBufferSize(&audio->left) / 2;
+#else
+	if ((size_t) blip_samples_avail(audio->left) < audio->samples) {
+		blip_add_delta(audio->left, audio->clock, sampleLeft - audio->lastLeft);
+		blip_add_delta(audio->right, audio->clock, sampleRight - audio->lastRight);
+		audio->lastLeft = sampleLeft;
+		audio->lastRight = sampleRight;
+		audio->clock += audio->sampleInterval;
+		int clockNeeded = blip_clocks_needed(audio->left, audio->samples / 32);
+		if (audio->clock >= clockNeeded) {
+			blip_end_frame(audio->left, audio->clock);
+			blip_end_frame(audio->right, audio->clock);
+			audio->clock -= clockNeeded;
+		}
+	}
+	produced = blip_samples_avail(audio->left);
+#endif
 	struct GBAThread* thread = GBAThreadGetContext();
 	if (thread && thread->stream) {
 		thread->stream->postAudioFrame(thread->stream, sampleLeft, sampleRight);
 	}
-	GBASyncProduceAudio(audio->p->sync, produced >= CircleBufferCapacity(&audio->left));
+	GBASyncProduceAudio(audio->p->sync, produced >= audio->samples);
 }
 
 void GBAAudioSerialize(const struct GBAAudio* audio, struct GBASerializedState* state) {

@@ -11,9 +11,16 @@ #include "macros.h"
 
 #include "util/circle-buffer.h"
 
+#if RESAMPLE_LIBRARY == RESAMPLE_BLIP_BUF
+#include "third-party/blip_buf/blip_buf.h"
+#endif
+
 struct GBADMA;
 
 extern const unsigned GBA_AUDIO_SAMPLES;
+
+#define RESAMPLE_NN 0
+#define RESAMPLE_BLIP_BUF 2
 
 DECL_BITFIELD(GBAAudioRegisterEnvelope, uint16_t);
 DECL_BITS(GBAAudioRegisterEnvelope, Length, 0, 6);
@@ -177,8 +184,16 @@
 	struct GBAAudioFIFO chA;
 	struct GBAAudioFIFO chB;
 
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	struct CircleBuffer left;
 	struct CircleBuffer right;
+#else
+	blip_t* left;
+	blip_t* right;
+	int16_t lastLeft;
+	int16_t lastRight;
+	int clock;
+#endif
 
 	uint8_t volumeRight;
 	uint8_t volumeLeft;
@@ -207,6 +222,7 @@ bool playingCh3;
 	bool playingCh4;
 	bool enable;
 
+	size_t samples;
 	unsigned sampleRate;
 
 	GBARegisterSOUNDBIAS soundbias;
@@ -256,8 +272,10 @@ void GBAAudioWriteFIFO16(struct GBAAudio* audio, int address, uint16_t value);
 void GBAAudioWriteFIFO(struct GBAAudio* audio, int address, uint32_t value);
 void GBAAudioSampleFIFO(struct GBAAudio* audio, int fifoId, int32_t cycles);
 
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 unsigned GBAAudioCopy(struct GBAAudio* audio, void* left, void* right, unsigned nSamples);
 unsigned GBAAudioResampleNN(struct GBAAudio*, float ratio, float* drift, struct GBAStereoSample* output, unsigned nSamples);
+#endif
 
 struct GBASerializedState;
 void GBAAudioSerialize(const struct GBAAudio* audio, struct GBASerializedState* state);

@@ -1,64 +0,0 @@
-/* Copyright (c) 2013-2014 Jeffrey Pfau
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-#include "ffmpeg-resample.h"
-
-#include "gba-audio.h"
-
-#include <libavresample/avresample.h>
-#include <libavutil/opt.h>
-
-struct AVAudioResampleContext* GBAAudioOpenLAVR(unsigned inputRate, unsigned outputRate) {
-	AVAudioResampleContext *avr = avresample_alloc_context();
-	av_opt_set_int(avr, "in_channel_layout", AV_CH_LAYOUT_STEREO, 0);
-	av_opt_set_int(avr, "out_channel_layout", AV_CH_LAYOUT_STEREO, 0);
-	av_opt_set_int(avr, "in_sample_rate", inputRate, 0);
-	av_opt_set_int(avr, "out_sample_rate", outputRate, 0);
-	av_opt_set_int(avr, "in_sample_fmt", AV_SAMPLE_FMT_S16P, 0);
-	av_opt_set_int(avr, "out_sample_fmt", AV_SAMPLE_FMT_S16, 0);
-	if (avresample_open(avr)) {
-		avresample_free(&avr);
-		return 0;
-	}
-	return avr;
-}
-
-struct AVAudioResampleContext* GBAAudioReopenLAVR(struct AVAudioResampleContext* avr, unsigned inputRate, unsigned outputRate) {
-	avresample_close(avr);
-	av_opt_set_int(avr, "in_sample_rate", inputRate, 0);
-	av_opt_set_int(avr, "out_sample_rate", outputRate, 0);
-	if (avresample_open(avr)) {
-		avresample_free(&avr);
-		return 0;
-	}
-	return avr;
-}
-
-unsigned GBAAudioResampleLAVR(struct GBAAudio* audio, struct AVAudioResampleContext* avr, struct GBAStereoSample* output, unsigned nSamples) {
-	int16_t left[GBA_AUDIO_SAMPLES];
-	int16_t right[GBA_AUDIO_SAMPLES];
-	int16_t* samples[2] = { left, right };
-
-	size_t totalRead = 0;
-	size_t available = avresample_available(avr);
-	if (available) {
-		totalRead = avresample_read(avr, (uint8_t**) &output, nSamples);
-		nSamples -= totalRead;
-		output += totalRead;
-	}
-	while (nSamples) {
-		unsigned read = GBAAudioCopy(audio, left, right, GBA_AUDIO_SAMPLES);
-		if (read == 0) {
-			memset(output, 0, nSamples * sizeof(struct GBAStereoSample));
-			break;
-		}
-
-		size_t currentRead = avresample_convert(avr, (uint8_t**) &output, nSamples * sizeof(struct GBAStereoSample), nSamples, (uint8_t**) samples, sizeof(left), read);
-		nSamples -= currentRead;
-		output += currentRead;
-		totalRead += currentRead;
-	}
-	return totalRead;
-}

@@ -1,17 +0,0 @@
-/* Copyright (c) 2013-2014 Jeffrey Pfau
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-#ifndef FFMPEG_RESAMPLE
-#define FFMPEG_RESAMPLE
-
-struct AVAudioResampleContext;
-struct GBAAudio;
-struct GBAStereoSample;
-
-struct AVAudioResampleContext* GBAAudioOpenLAVR(unsigned inputRate, unsigned outputRate);
-struct AVAudioResampleContext* GBAAudioReopenLAVR(struct AVAudioResampleContext* avr, unsigned inputRate, unsigned outputRate);
-unsigned GBAAudioResampleLAVR(struct GBAAudio* audio, struct AVAudioResampleContext* avr, struct GBAStereoSample* output, unsigned nSamples);
-
-#endif

@@ -369,6 +369,7 @@ m_threadContext.activeKeys = activeKeys;
 }
 
 void GameController::redoSamples(int samples) {
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	float sampleRate = 0x8000;
 	float ratio;
 	if (m_threadContext.gba) {
@@ -376,6 +377,9 @@ sampleRate = m_threadContext.gba->audio.sampleRate;
 	}
 	ratio = GBAAudioCalculateRatio(sampleRate, m_threadContext.fpsTarget, 44100);
 	m_threadContext.audioBuffers = ceil(samples / ratio);
+#else
+	m_threadContext.audioBuffers = samples;
+#endif
 	if (m_threadContext.gba) {
 		GBAAudioResizeBuffer(&m_threadContext.gba->audio, m_threadContext.audioBuffers);
 	}

@@ -8,9 +8,8 @@
 #include "gba.h"
 #include "gba-thread.h"
 
-#ifdef USE_FFMPEG
-#include "platform/ffmpeg/ffmpeg-resample.h"
-#include <libavresample/avresample.h>
+#if RESAMPLE_LIBRARY == RESAMPLE_BLIP_BUF
+#include "third-party/blip_buf/blip_buf.h"
 #endif
 
 #define BUFFER_SIZE (GBA_AUDIO_SAMPLES >> 2)
@@ -29,7 +28,7 @@ context->desiredSpec.channels = 2;
 	context->desiredSpec.samples = context->samples;
 	context->desiredSpec.callback = _GBASDLAudioCallback;
 	context->desiredSpec.userdata = context;
-#ifndef USE_FFMPEG
+#if RESAMPLE_LIBRARY == RESAMPLE_NN
 	context->drift = 0.f;
 #endif
 	if (SDL_OpenAudio(&context->desiredSpec, &context->obtainedSpec) < 0) {
@@ -44,10 +43,6 @@ if (context->samples > threadContext->audioBuffers) {
 		threadContext->audioBuffers = context->samples * 2;
 	}
 
-#ifdef USE_FFMPEG
-	context->avr = 0;
-#endif
-
 	SDL_PauseAudio(0);
 	return true;
 }
@@ -57,9 +52,6 @@ UNUSED(context);
 	SDL_PauseAudio(1);
 	SDL_CloseAudio();
 	SDL_QuitSubSystem(SDL_INIT_AUDIO);
-#ifdef USE_FFMPEG
-	avresample_free(&context->avr);
-#endif
 }
 
 void GBASDLPauseAudio(struct GBASDLAudio* context) {
@@ -78,7 +70,7 @@ if (!context || !audioContext->thread || !audioContext->thread->gba) {
 		memset(data, 0, len);
 		return;
 	}
-#ifndef USE_FFMPEG
+#if RESAMPLE_LIBRARY == RESAMPLE_NN
 	audioContext->ratio = GBAAudioCalculateRatio(audioContext->thread->gba->audio.sampleRate, audioContext->thread->fpsTarget, audioContext->obtainedSpec.freq);
 	if (audioContext->ratio == INFINITY) {
 		memset(data, 0, len);
@@ -89,21 +81,23 @@ len /= 2 * audioContext->obtainedSpec.channels;
 	if (audioContext->obtainedSpec.channels == 2) {
 		GBAAudioResampleNN(&audioContext->thread->gba->audio, audioContext->ratio, &audioContext->drift, ssamples, len);
 	}
-#else
-	float ratio = GBAAudioCalculateRatio(audioContext->thread->gba->audio.sampleRate, audioContext->thread->fpsTarget, audioContext->thread->gba->audio.sampleRate);
-	if (!audioContext->avr) {
-		if (!audioContext->thread->gba->audio.sampleRate) {
-			memset(data, 0, len);
-			return;
-		}
-		audioContext->ratio = ratio;
-		audioContext->avr = GBAAudioOpenLAVR(audioContext->thread->gba->audio.sampleRate / ratio, audioContext->obtainedSpec.freq);
-	} else if (ratio != audioContext->ratio) {
-		audioContext->ratio = ratio;
-		audioContext->avr = GBAAudioReopenLAVR(audioContext->avr, audioContext->thread->gba->audio.sampleRate / ratio, audioContext->obtainedSpec.freq);
-	}
-	struct GBAStereoSample* ssamples = (struct GBAStereoSample*) data;
+#elif RESAMPLE_LIBRARY == RESAMPLE_BLIP_BUF
+	double fauxClock = GBAAudioCalculateRatio(1, audioContext->thread->fpsTarget, 1);
+	GBASyncLockAudio(&audioContext->thread->sync);
+	blip_set_rates(audioContext->thread->gba->audio.left, GBA_ARM7TDMI_FREQUENCY, audioContext->obtainedSpec.freq * fauxClock);
+	blip_set_rates(audioContext->thread->gba->audio.right, GBA_ARM7TDMI_FREQUENCY, audioContext->obtainedSpec.freq * fauxClock);
 	len /= 2 * audioContext->obtainedSpec.channels;
-	GBAAudioResampleLAVR(&audioContext->thread->gba->audio, audioContext->avr, ssamples, len);
+	int available = blip_samples_avail(audioContext->thread->gba->audio.left);
+	if (available > len) {
+		available = len;
+	}
+	blip_read_samples(audioContext->thread->gba->audio.left, (short*) data, available, audioContext->obtainedSpec.channels == 2);
+	if (audioContext->obtainedSpec.channels == 2) {
+		blip_read_samples(audioContext->thread->gba->audio.right, ((short*) data) + 1, available, 1);
+	}
+	GBASyncConsumeAudio(&audioContext->thread->sync);
+	if (available < len) {
+		memset(((short*) data) + audioContext->obtainedSpec.channels * available, 0, len - available);
+	}
 #endif
 }

@@ -10,6 +10,8 @@ #include "util/common.h"
 
 #include <SDL.h>
 
+#include "gba-audio.h"
+
 struct GBASDLAudio {
 	// Input
 	size_t samples;
@@ -17,11 +19,11 @@
 	// State
 	SDL_AudioSpec desiredSpec;
 	SDL_AudioSpec obtainedSpec;
+#if RESAMPLE_LIBRARY != RESAMPLE_BLIP_BUF
 	float ratio;
-#ifndef USE_FFMPEG
+#endif
+#if RESAMPLE_LIBRARY == RESAMPLE_NN
 	float drift;
-#else
-	struct AVAudioResampleContext* avr;
 #endif
 
 	struct GBAThread* thread;

@@ -0,0 +1,344 @@
+/* blip_buf 1.1.0. http://www.slack.net/~ant/ */
+
+#include "blip_buf.h"
+
+#include <assert.h>
+#include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+
+/* Library Copyright (C) 2003-2009 Shay Green. This library is free software;
+you can redistribute it and/or modify it under the terms of the GNU Lesser
+General Public License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version. This
+library is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+details. You should have received a copy of the GNU Lesser General Public
+License along with this module; if not, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
+
+#if defined (BLARGG_TEST) && BLARGG_TEST
+	#include "blargg_test.h"
+#endif
+
+/* Equivalent to ULONG_MAX >= 0xFFFFFFFF00000000.
+Avoids constants that don't fit in 32 bits. */
+#if ULONG_MAX/0xFFFFFFFF > 0xFFFFFFFF
+	typedef unsigned long fixed_t;
+	enum { pre_shift = 32 };
+
+#elif defined(ULLONG_MAX)
+	typedef unsigned long long fixed_t;
+	enum { pre_shift = 32 };
+
+#else
+	typedef unsigned fixed_t;
+	enum { pre_shift = 0 };
+
+#endif
+
+enum { time_bits = pre_shift + 20 };
+
+static fixed_t const time_unit = (fixed_t) 1 << time_bits;
+
+enum { bass_shift  = 9 }; /* affects high-pass filter breakpoint frequency */
+enum { end_frame_extra = 2 }; /* allows deltas slightly after frame length */
+
+enum { half_width  = 8 };
+enum { buf_extra   = half_width*2 + end_frame_extra };
+enum { phase_bits  = 5 };
+enum { phase_count = 1 << phase_bits };
+enum { delta_bits  = 15 };
+enum { delta_unit  = 1 << delta_bits };
+enum { frac_bits = time_bits - pre_shift };
+
+/* We could eliminate avail and encode whole samples in offset, but that would
+limit the total buffered samples to blip_max_frame. That could only be
+increased by decreasing time_bits, which would reduce resample ratio accuracy.
+*/
+
+/** Sample buffer that resamples to output rate and accumulates samples
+until they're read out */
+struct blip_t
+{
+	fixed_t factor;
+	fixed_t offset;
+	int avail;
+	int size;
+	int integrator;
+};
+
+typedef int buf_t;
+
+/* probably not totally portable */
+#define SAMPLES( buf ) ((buf_t*) ((buf) + 1))
+
+/* Arithmetic (sign-preserving) right shift */
+#define ARITH_SHIFT( n, shift ) \
+	((n) >> (shift))
+
+enum { max_sample = +32767 };
+enum { min_sample = -32768 };
+
+#define CLAMP( n ) \
+	{\
+		if ( (short) n != n )\
+			n = ARITH_SHIFT( n, 16 ) ^ max_sample;\
+	}
+
+static void check_assumptions( void )
+{
+	int n;
+	
+	#if INT_MAX < 0x7FFFFFFF || UINT_MAX < 0xFFFFFFFF
+		#error "int must be at least 32 bits"
+	#endif
+	
+	assert( (-3 >> 1) == -2 ); /* right shift must preserve sign */
+	
+	n = max_sample * 2;
+	CLAMP( n );
+	assert( n == max_sample );
+	
+	n = min_sample * 2;
+	CLAMP( n );
+	assert( n == min_sample );
+	
+	assert( blip_max_ratio <= time_unit );
+	assert( blip_max_frame <= (fixed_t) -1 >> time_bits );
+}
+
+blip_t* blip_new( int size )
+{
+	blip_t* m;
+	assert( size >= 0 );
+	
+	m = (blip_t*) malloc( sizeof *m + (size + buf_extra) * sizeof (buf_t) );
+	if ( m )
+	{
+		m->factor = time_unit / blip_max_ratio;
+		m->size   = size;
+		blip_clear( m );
+		check_assumptions();
+	}
+	return m;
+}
+
+void blip_delete( blip_t* m )
+{
+	if ( m != NULL )
+	{
+		/* Clear fields in case user tries to use after freeing */
+		memset( m, 0, sizeof *m );
+		free( m );
+	}
+}
+
+void blip_set_rates( blip_t* m, double clock_rate, double sample_rate )
+{
+	double factor = time_unit * sample_rate / clock_rate;
+	m->factor = (fixed_t) factor;
+	
+	/* Fails if clock_rate exceeds maximum, relative to sample_rate */
+	assert( 0 <= factor - m->factor && factor - m->factor < 1 );
+	
+	/* Avoid requiring math.h. Equivalent to
+	m->factor = (int) ceil( factor ) */
+	if ( m->factor < factor )
+		m->factor++;
+	
+	/* At this point, factor is most likely rounded up, but could still
+	have been rounded down in the floating-point calculation. */
+}
+
+void blip_clear( blip_t* m )
+{
+	/* We could set offset to 0, factor/2, or factor-1. 0 is suitable if
+	factor is rounded up. factor-1 is suitable if factor is rounded down.
+	Since we don't know rounding direction, factor/2 accommodates either,
+	with the slight loss of showing an error in half the time. Since for
+	a 64-bit factor this is years, the halving isn't a problem. */
+	
+	m->offset     = m->factor / 2;
+	m->avail      = 0;
+	m->integrator = 0;
+	memset( SAMPLES( m ), 0, (m->size + buf_extra) * sizeof (buf_t) );
+}
+
+int blip_clocks_needed( const blip_t* m, int samples )
+{
+	fixed_t needed;
+	
+	/* Fails if buffer can't hold that many more samples */
+	assert( samples >= 0 && m->avail + samples <= m->size );
+	
+	needed = (fixed_t) samples * time_unit;
+	if ( needed < m->offset )
+		return 0;
+	
+	return (needed - m->offset + m->factor - 1) / m->factor;
+}
+
+void blip_end_frame( blip_t* m, unsigned t )
+{
+	fixed_t off = t * m->factor + m->offset;
+	m->avail += off >> time_bits;
+	m->offset = off & (time_unit - 1);
+	
+	/* Fails if buffer size was exceeded */
+	assert( m->avail <= m->size );
+}
+
+int blip_samples_avail( const blip_t* m )
+{
+	return m->avail;
+}
+
+static void remove_samples( blip_t* m, int count )
+{
+	buf_t* buf = SAMPLES( m );
+	int remain = m->avail + buf_extra - count;
+	m->avail -= count;
+	
+	memmove( &buf [0], &buf [count], remain * sizeof buf [0] );
+	memset( &buf [remain], 0, count * sizeof buf [0] );
+}
+
+int blip_read_samples( blip_t* m, short out [], int count, int stereo )
+{
+	assert( count >= 0 );
+	
+	if ( count > m->avail )
+		count = m->avail;
+	
+	if ( count )
+	{
+		int const step = stereo ? 2 : 1;
+		buf_t const* in  = SAMPLES( m );
+		buf_t const* end = in + count;
+		int sum = m->integrator;
+		do
+		{
+			/* Eliminate fraction */
+			int s = ARITH_SHIFT( sum, delta_bits );
+			
+			sum += *in++;
+			
+			CLAMP( s );
+			
+			*out = s;
+			out += step;
+			
+			/* High-pass filter */
+			sum -= s << (delta_bits - bass_shift);
+		}
+		while ( in != end );
+		m->integrator = sum;
+		
+		remove_samples( m, count );
+	}
+	
+	return count;
+}
+
+/* Things that didn't help performance on x86:
+	__attribute__((aligned(128)))
+	#define short int
+	restrict
+*/
+
+/* Sinc_Generator( 0.9, 0.55, 4.5 ) */
+static short const bl_step [phase_count + 1] [half_width] =
+{
+{   43, -115,  350, -488, 1136, -914, 5861,21022},
+{   44, -118,  348, -473, 1076, -799, 5274,21001},
+{   45, -121,  344, -454, 1011, -677, 4706,20936},
+{   46, -122,  336, -431,  942, -549, 4156,20829},
+{   47, -123,  327, -404,  868, -418, 3629,20679},
+{   47, -122,  316, -375,  792, -285, 3124,20488},
+{   47, -120,  303, -344,  714, -151, 2644,20256},
+{   46, -117,  289, -310,  634,  -17, 2188,19985},
+{   46, -114,  273, -275,  553,  117, 1758,19675},
+{   44, -108,  255, -237,  471,  247, 1356,19327},
+{   43, -103,  237, -199,  390,  373,  981,18944},
+{   42,  -98,  218, -160,  310,  495,  633,18527},
+{   40,  -91,  198, -121,  231,  611,  314,18078},
+{   38,  -84,  178,  -81,  153,  722,   22,17599},
+{   36,  -76,  157,  -43,   80,  824, -241,17092},
+{   34,  -68,  135,   -3,    8,  919, -476,16558},
+{   32,  -61,  115,   34,  -60, 1006, -683,16001},
+{   29,  -52,   94,   70, -123, 1083, -862,15422},
+{   27,  -44,   73,  106, -184, 1152,-1015,14824},
+{   25,  -36,   53,  139, -239, 1211,-1142,14210},
+{   22,  -27,   34,  170, -290, 1261,-1244,13582},
+{   20,  -20,   16,  199, -335, 1301,-1322,12942},
+{   18,  -12,   -3,  226, -375, 1331,-1376,12293},
+{   15,   -4,  -19,  250, -410, 1351,-1408,11638},
+{   13,    3,  -35,  272, -439, 1361,-1419,10979},
+{   11,    9,  -49,  292, -464, 1362,-1410,10319},
+{    9,   16,  -63,  309, -483, 1354,-1383, 9660},
+{    7,   22,  -75,  322, -496, 1337,-1339, 9005},
+{    6,   26,  -85,  333, -504, 1312,-1280, 8355},
+{    4,   31,  -94,  341, -507, 1278,-1205, 7713},
+{    3,   35, -102,  347, -506, 1238,-1119, 7082},
+{    1,   40, -110,  350, -499, 1190,-1021, 6464},
+{    0,   43, -115,  350, -488, 1136, -914, 5861}
+};
+
+/* Shifting by pre_shift allows calculation using unsigned int rather than
+possibly-wider fixed_t. On 32-bit platforms, this is likely more efficient.
+And by having pre_shift 32, a 32-bit platform can easily do the shift by
+simply ignoring the low half. */
+
+void blip_add_delta( blip_t* m, unsigned time, int delta )
+{
+	unsigned fixed = (unsigned) ((time * m->factor + m->offset) >> pre_shift);
+	buf_t* out = SAMPLES( m ) + m->avail + (fixed >> frac_bits);
+	
+	int const phase_shift = frac_bits - phase_bits;
+	int phase = fixed >> phase_shift & (phase_count - 1);
+	short const* in  = bl_step [phase];
+	short const* rev = bl_step [phase_count - phase];
+	
+	int interp = fixed >> (phase_shift - delta_bits) & (delta_unit - 1);
+	int delta2 = (delta * interp) >> delta_bits;
+	delta -= delta2;
+	
+	/* Fails if buffer size was exceeded */
+	assert( out <= &SAMPLES( m ) [m->size + end_frame_extra] );
+	
+	out [0] += in[0]*delta + in[half_width+0]*delta2;
+	out [1] += in[1]*delta + in[half_width+1]*delta2;
+	out [2] += in[2]*delta + in[half_width+2]*delta2;
+	out [3] += in[3]*delta + in[half_width+3]*delta2;
+	out [4] += in[4]*delta + in[half_width+4]*delta2;
+	out [5] += in[5]*delta + in[half_width+5]*delta2;
+	out [6] += in[6]*delta + in[half_width+6]*delta2;
+	out [7] += in[7]*delta + in[half_width+7]*delta2;
+	
+	in = rev;
+	out [ 8] += in[7]*delta + in[7-half_width]*delta2;
+	out [ 9] += in[6]*delta + in[6-half_width]*delta2;
+	out [10] += in[5]*delta + in[5-half_width]*delta2;
+	out [11] += in[4]*delta + in[4-half_width]*delta2;
+	out [12] += in[3]*delta + in[3-half_width]*delta2;
+	out [13] += in[2]*delta + in[2-half_width]*delta2;
+	out [14] += in[1]*delta + in[1-half_width]*delta2;
+	out [15] += in[0]*delta + in[0-half_width]*delta2;
+}
+
+void blip_add_delta_fast( blip_t* m, unsigned time, int delta )
+{
+	unsigned fixed = (unsigned) ((time * m->factor + m->offset) >> pre_shift);
+	buf_t* out = SAMPLES( m ) + m->avail + (fixed >> frac_bits);
+	
+	int interp = fixed >> (frac_bits - delta_bits) & (delta_unit - 1);
+	int delta2 = delta * interp;
+	
+	/* Fails if buffer size was exceeded */
+	assert( out <= &SAMPLES( m ) [m->size + end_frame_extra] );
+	
+	out [7] += delta * delta_unit - delta2;
+	out [8] += delta2;
+}

@@ -0,0 +1,72 @@
+/** \file
+Sample buffer that resamples from input clock rate to output sample rate */
+
+/* blip_buf 1.1.0 */
+#ifndef BLIP_BUF_H 
+#define BLIP_BUF_H
+
+#ifdef __cplusplus
+	extern "C" {
+#endif
+
+/** First parameter of most functions is blip_t*, or const blip_t* if nothing
+is changed. */
+typedef struct blip_t blip_t;
+
+/** Creates new buffer that can hold at most sample_count samples. Sets rates
+so that there are blip_max_ratio clocks per sample. Returns pointer to new
+buffer, or NULL if insufficient memory. */
+blip_t* blip_new( int sample_count );
+
+/** Sets approximate input clock rate and output sample rate. For every
+clock_rate input clocks, approximately sample_rate samples are generated. */
+void blip_set_rates( blip_t*, double clock_rate, double sample_rate );
+
+enum { /** Maximum clock_rate/sample_rate ratio. For a given sample_rate,
+clock_rate must not be greater than sample_rate*blip_max_ratio. */
+blip_max_ratio = 1 << 20 };
+
+/** Clears entire buffer. Afterwards, blip_samples_avail() == 0. */
+void blip_clear( blip_t* );
+
+/** Adds positive/negative delta into buffer at specified clock time. */
+void blip_add_delta( blip_t*, unsigned int clock_time, int delta );
+
+/** Same as blip_add_delta(), but uses faster, lower-quality synthesis. */
+void blip_add_delta_fast( blip_t*, unsigned int clock_time, int delta );
+
+/** Length of time frame, in clocks, needed to make sample_count additional
+samples available. */
+int blip_clocks_needed( const blip_t*, int sample_count );
+
+enum { /** Maximum number of samples that can be generated from one time frame. */
+blip_max_frame = 4000 };
+
+/** Makes input clocks before clock_duration available for reading as output
+samples. Also begins new time frame at clock_duration, so that clock time 0 in
+the new time frame specifies the same clock as clock_duration in the old time
+frame specified. Deltas can have been added slightly past clock_duration (up to
+however many clocks there are in two output samples). */
+void blip_end_frame( blip_t*, unsigned int clock_duration );
+
+/** Number of buffered samples available for reading. */
+int blip_samples_avail( const blip_t* );
+
+/** Reads and removes at most 'count' samples and writes them to 'out'. If
+'stereo' is true, writes output to every other element of 'out', allowing easy
+interleaving of two buffers into a stereo sample stream. Outputs 16-bit signed
+samples. Returns number of samples actually read.  */
+int blip_read_samples( blip_t*, short out [], int count, int stereo );
+
+/** Frees buffer. No effect if NULL is passed. */
+void blip_delete( blip_t* );
+
+
+/* Deprecated */
+typedef blip_t blip_buffer_t;
+
+#ifdef __cplusplus
+	}
+#endif
+
+#endif

@@ -0,0 +1,504 @@
+		  GNU LESSER GENERAL PUBLIC LICENSE
+		       Version 2.1, February 1999
+
+ Copyright (C) 1991, 1999 Free Software Foundation, Inc.
+ 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+[This is the first released version of the Lesser GPL.  It also counts
+ as the successor of the GNU Library Public License, version 2, hence
+ the version number 2.1.]
+
+			    Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+Licenses are intended to guarantee your freedom to share and change
+free software--to make sure the software is free for all its users.
+
+  This license, the Lesser General Public License, applies to some
+specially designated software packages--typically libraries--of the
+Free Software Foundation and other authors who decide to use it.  You
+can use it too, but we suggest you first think carefully about whether
+this license or the ordinary General Public License is the better
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+
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+
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