From 63deff31a441647619080ca046d1aa1c8edcea9e Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Tue, 10 Mar 2015 00:18:56 +0100
Subject: [PATCH] Use float samples internally.

---
 audioreader.cpp | 14 +++++++-------
 audioreader.h   |  2 +-
 decode.cpp      |  4 ++--
 interpolate.h   |  4 ++--
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/audioreader.cpp b/audioreader.cpp
index f0d07d8..e133afc 100644
--- a/audioreader.cpp
+++ b/audioreader.cpp
@@ -50,25 +50,25 @@ struct AVSampleDeleter {
 	}
 };
 
-void convert_samples(SwrContext *swr, int sample_rate, const uint8_t **data, int nb_samples, std::vector<int16_t> *samples)
+void convert_samples(SwrContext *swr, int sample_rate, const uint8_t **data, int nb_samples, std::vector<float> *samples)
 {
 	int max_out_samples = nb_samples + swr_get_delay(swr, sample_rate);
 	if (max_out_samples == 0) {
 		return;
 	}
 	uint8_t *output;
-	av_samples_alloc(&output, nullptr, 1, max_out_samples, AV_SAMPLE_FMT_S16, 0);
+	av_samples_alloc(&output, nullptr, 1, max_out_samples, AV_SAMPLE_FMT_FLT, 0);
 	std::unique_ptr<uint8_t, AVSampleDeleter> output_deleter(output);
 
 	int out_samples = swr_convert(swr, &output, max_out_samples, data, nb_samples);
 	if (out_samples > 0) {
-		const int16_t* start = reinterpret_cast<const int16_t *>(output);
-		const int16_t* end = start + out_samples;
+		const float* start = reinterpret_cast<const float *>(output);
+		const float* end = start + out_samples;
 		samples->insert(samples->end(), start, end);
 	}
 }
 
-int decode_packet(const char *filename, AVCodecContext *codec_ctx, SwrContext *swr, AVFrame *audio_frame, AVPacket *packet, int *got_frame, std::vector<int16_t> *samples)
+int decode_packet(const char *filename, AVCodecContext *codec_ctx, SwrContext *swr, AVFrame *audio_frame, AVPacket *packet, int *got_frame, std::vector<float> *samples)
 {
 	*got_frame = 0;
 	int len1 = avcodec_decode_audio4(codec_ctx, audio_frame, got_frame, packet);
@@ -88,7 +88,7 @@ int decode_packet(const char *filename, AVCodecContext *codec_ctx, SwrContext *s
 
 }  // namespace
 
-bool read_audio_file(const char *filename, std::vector<int16_t> *samples, int *sample_rate)
+bool read_audio_file(const char *filename, std::vector<float> *samples, int *sample_rate)
 {
 	av_register_all();
 
@@ -141,7 +141,7 @@ bool read_audio_file(const char *filename, std::vector<int16_t> *samples, int *s
 	}
 	SwrContext *swr = swr_alloc_set_opts(
 		nullptr,
-		AV_CH_LAYOUT_MONO, AV_SAMPLE_FMT_S16, codec_ctx->sample_rate,
+		AV_CH_LAYOUT_MONO, AV_SAMPLE_FMT_FLT, codec_ctx->sample_rate,
 		codec_ctx->channel_layout, codec_ctx->sample_fmt, codec_ctx->sample_rate,
 		0, nullptr);
 	std::unique_ptr<SwrContext, SwrContextDeleter> swr_deleter(swr);
diff --git a/audioreader.h b/audioreader.h
index 47bb8f5..c654b61 100644
--- a/audioreader.h
+++ b/audioreader.h
@@ -5,6 +5,6 @@
 
 #include <stdint.h>
 
-bool read_audio_file(const char *filename, std::vector<int16_t> *samples, int *sample_rate);
+bool read_audio_file(const char *filename, std::vector<float> *samples, int *sample_rate);
 
 #endif  // !defined(_AUDIOREADER_H)
diff --git a/decode.cpp b/decode.cpp
index 8ed2f1b..5bb3b2c 100644
--- a/decode.cpp
+++ b/decode.cpp
@@ -20,7 +20,7 @@
 #define SYNC_TEST_TOLERANCE 1.10
 
 // between [x,x+1]
-double find_zerocrossing(const std::vector<short> &pcm, int x)
+double find_zerocrossing(const std::vector<float> &pcm, int x)
 {
 	if (pcm[x] == 0) {
 		return x;
@@ -107,7 +107,7 @@ double calibrate(const std::vector<pulse> &pulses) {
 int main(int argc, char **argv)
 {
 	make_lanczos_weight_table();
-	std::vector<short> pcm;
+	std::vector<float> pcm;
 	int sample_rate;
 	if (!read_audio_file(argv[1], &pcm, &sample_rate)) {
 		exit(1);
diff --git a/interpolate.h b/interpolate.h
index f9aeb11..c71110b 100644
--- a/interpolate.h
+++ b/interpolate.h
@@ -29,9 +29,9 @@ inline double lanczos_weight(double x)
 extern double lanczos_table[LANCZOS_RADIUS * LANCZOS_RESOLUTION];
 void make_lanczos_weight_table();
 
-inline double lanczos_weight_table(double x)
+inline double lanczos_weight_table(float x)
 {
-	int table_id = lrintf(fabs(x) * LANCZOS_RESOLUTION);
+	int table_id = lrintf(fabsf(x) * LANCZOS_RESOLUTION);
 	if (table_id >= LANCZOS_RADIUS * LANCZOS_RESOLUTION) {
 		return 0.0;
 	}
-- 
2.39.2