Allow build to exclude internal avresample (#77)

This allows the build to complete without using FFmpeg-derived code,
though this disables input resampling and thus requires that input
audio to the fingerprinter is already at the configured fingerprint
sample rate.

Co-authored-by: Lukáš Lalinský <lalinsky@gmail.com>

CMakeLists.txt

@@ -15,6 +15,8 @@ set_property(CACHE AUDIO_PROCESSOR_LIB PROPERTY STRINGS avresample swresample)
 set(FFT_LIB CACHE STRING "Library to use for FFT calculations")
 set_property(CACHE FFT_LIB PROPERTY STRINGS avfft fftw3 fftw3f kissfft vdsp)
 
+option(USE_INTERNAL_AVRESAMPLE "Use internal copy of avresample from ffmpeg for input conversion" ON)
+
 include(CMakePushCheckState)
 include(CheckFunctionExists)
 include(CheckSymbolExists)

config.h.in

@@ -8,6 +8,7 @@
 
 #cmakedefine USE_SWRESAMPLE 1
 #cmakedefine USE_AVRESAMPLE 1
+#cmakedefine USE_INTERNAL_AVRESAMPLE 1
 
 #cmakedefine USE_AVFFT 1
 #cmakedefine USE_FFTW3 1

src/CMakeLists.txt

@@ -25,7 +25,6 @@ set(chromaprint_SOURCES
 	utils/scope_exit.h
 	utils/rolling_integral_image.h
 	audio/audio_slicer.h
-	avresample/resample2.c
 )
 
 set(chromaprint_PUBLIC_SOURCES chromaprint.cpp)
@@ -65,6 +64,10 @@ if(USE_KISSFFT)
 	include_directories(${KISSFFT_INCLUDE_DIRS})
 endif()
 
+if (USE_INTERNAL_AVRESAMPLE)
+  set(chromaprint_SOURCES avresample/resample2.c ${chromaprint_SOURCES})
+endif()
+
 add_library(chromaprint_objs OBJECT ${chromaprint_SOURCES})
 if(BUILD_SHARED_LIBS)
 	set_target_properties(chromaprint_objs PROPERTIES POSITION_INDEPENDENT_CODE TRUE)

src/audio_processor.cpp

@@ -4,9 +4,16 @@
 #include <assert.h>
 #include <algorithm>
 #include <stdio.h>
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#if USE_INTERNAL_AVRESAMPLE
 extern "C" {
 #include "avresample/avcodec.h"
 }
+#endif
+
 #include "debug.h"
 #include "audio_processor.h"
 
@@ -15,11 +22,13 @@ namespace chromaprint {
 static const int kMinSampleRate = 1000;
 static const int kMaxBufferSize = 1024 * 32;
 
+#if USE_INTERNAL_AVRESAMPLE
 // Resampler configuration
 static const int kResampleFilterLength = 16;
 static const int kResamplePhaseShift = 8;
 static const int kResampleLinear = 0;
 static const double kResampleCutoff = 0.8;
+#endif
 
 AudioProcessor::AudioProcessor(int sample_rate, AudioConsumer *consumer)
 	: m_buffer(kMaxBufferSize),
@@ -33,9 +42,11 @@ AudioProcessor::AudioProcessor(int sample_rate, AudioConsumer *consumer)
 
 AudioProcessor::~AudioProcessor()
 {
+#if USE_INTERNAL_AVRESAMPLE
 	if (m_resample_ctx) {
 		av_resample_close(m_resample_ctx);
 	}
+#endif
 }
 
 void AudioProcessor::LoadMono(const int16_t *input, int length)
@@ -90,27 +101,30 @@ int AudioProcessor::Load(const int16_t *input, int length)
 
 void AudioProcessor::Resample()
 {
-	if (!m_resample_ctx) {
+#if USE_INTERNAL_AVRESAMPLE
+	if (m_resample_ctx) {
+		int consumed = 0;
+  	int length = av_resample(m_resample_ctx, m_resample_buffer.data(), m_buffer.data(), &consumed, int(m_buffer_offset), kMaxBufferSize, 1);
+		if (length > kMaxBufferSize) {
+			DEBUG("chromaprint::AudioProcessor::Resample() -- Resampling overwrote output buffer.");
+			length = kMaxBufferSize;
+		}
+		m_consumer->Consume(m_resample_buffer.data(), length);
+  	int remaining = int(m_buffer_offset - consumed);
+		if (remaining > 0) {
+			std::copy(m_buffer.begin() + consumed, m_buffer.begin() + m_buffer_offset, m_buffer.begin());
+		}
+		else if (remaining < 0) {
+			DEBUG("chromaprint::AudioProcessor::Resample() -- Resampling overread input buffer.");
+			remaining = 0;
+		}
+		m_buffer_offset = remaining;
+	} else
+#endif
+	{
 		m_consumer->Consume(m_buffer.data(), int(m_buffer_offset));
 		m_buffer_offset = 0;
-		return;
-	}
-	int consumed = 0;
-	int length = av_resample(m_resample_ctx, m_resample_buffer.data(), m_buffer.data(), &consumed, int(m_buffer_offset), kMaxBufferSize, 1);
-	if (length > kMaxBufferSize) {
-		DEBUG("chromaprint::AudioProcessor::Resample() -- Resampling overwrote output buffer.");
-		length = kMaxBufferSize;
 	}
-	m_consumer->Consume(m_resample_buffer.data(), length);
-	int remaining = int(m_buffer_offset - consumed);
-	if (remaining > 0) {
-		std::copy(m_buffer.begin() + consumed, m_buffer.begin() + m_buffer_offset, m_buffer.begin());
-	}
-	else if (remaining < 0) {
-		DEBUG("chromaprint::AudioProcessor::Resample() -- Resampling overread input buffer.");
-		remaining = 0;
-	}
-	m_buffer_offset = remaining;
 }
 
 
@@ -126,6 +140,8 @@ bool AudioProcessor::Reset(int sample_rate, int num_channels)
 		return false;
 	}
 	m_buffer_offset = 0;
+
+#if USE_INTERNAL_AVRESAMPLE
 	if (m_resample_ctx) {
 		av_resample_close(m_resample_ctx);
 		m_resample_ctx = 0;
@@ -138,6 +154,13 @@ bool AudioProcessor::Reset(int sample_rate, int num_channels)
 			kResampleLinear,
 			kResampleCutoff);
 	}
+#else
+	if (sample_rate != m_target_sample_rate) {
+		DEBUG("chromaprint::AudioProcessor::Reset() -- Cannot resample from " << sample_rate
+		           << " to " << m_target_sample_rate << " without internal avresample.");
+		return false;
+	}
+#endif
 	m_num_channels = num_channels;
 	return true;
 }