From: Steinar H. Gunderson <steinar+nageru@gunderson.no>
Date: Sun, 11 Aug 2019 08:50:50 +0000 (+0200)
Subject: Factor out a convert_audio_to_fp32() function.
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=a944bad466ba5601a96f6833e1ea2eb31f9b55af;p=nageru

Factor out a convert_audio_to_fp32() function.
---

diff --git a/nageru/audio_mixer.cpp b/nageru/audio_mixer.cpp
index a095c17..35e0a23 100644
--- a/nageru/audio_mixer.cpp
+++ b/nageru/audio_mixer.cpp
@@ -330,23 +330,7 @@ bool AudioMixer::add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned
 	unique_ptr<float[]> audio(new float[num_samples * num_channels]);
 	unsigned channel_index = 0;
 	for (auto channel_it = device->interesting_channels.cbegin(); channel_it != device->interesting_channels.end(); ++channel_it, ++channel_index) {
-		switch (audio_format.bits_per_sample) {
-		case 0:
-			assert(num_samples == 0);
-			break;
-		case 16:
-			convert_fixed16_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format.num_channels, num_samples);
-			break;
-		case 24:
-			convert_fixed24_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format.num_channels, num_samples);
-			break;
-		case 32:
-			convert_fixed32_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format.num_channels, num_samples);
-			break;
-		default:
-			fprintf(stderr, "Cannot handle audio with %u bits per sample\n", audio_format.bits_per_sample);
-			assert(false);
-		}
+		convert_audio_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format, num_samples);
 	}
 
 	// If we changed frequency since last frame, we'll need to reset the resampler.
@@ -360,6 +344,7 @@ bool AudioMixer::add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned
 	return true;
 }
 
+// Converts all channels.
 vector<int32_t> convert_audio_to_fixed32(const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, unsigned num_channels)
 {
 	vector<int32_t> audio;
@@ -392,6 +377,30 @@ vector<int32_t> convert_audio_to_fixed32(const uint8_t *data, unsigned num_sampl
 	return audio;
 }
 
+// Converts only one channel.
+void convert_audio_to_fp32(float *dst, size_t out_channel, size_t out_num_channels,
+                           const uint8_t *src, size_t in_channel, bmusb::AudioFormat in_audio_format,
+                           size_t num_samples)
+{
+	switch (in_audio_format.bits_per_sample) {
+	case 0:
+		assert(num_samples == 0);
+		break;
+	case 16:
+		convert_fixed16_to_fp32(dst, out_channel, out_num_channels, src, in_channel, in_audio_format.num_channels, num_samples);
+		break;
+	case 24:
+		convert_fixed24_to_fp32(dst, out_channel, out_num_channels, src, in_channel, in_audio_format.num_channels, num_samples);
+		break;
+	case 32:
+		convert_fixed32_to_fp32(dst, out_channel, out_num_channels, src, in_channel, in_audio_format.num_channels, num_samples);
+		break;
+	default:
+		fprintf(stderr, "Cannot handle audio with %u bits per sample\n", in_audio_format.bits_per_sample);
+		assert(false);
+	}
+}
+
 bool AudioMixer::add_silence(DeviceSpec device_spec, unsigned samples_per_frame, unsigned num_frames)
 {
 	AudioDevice *device = find_audio_device(device_spec);
diff --git a/nageru/audio_mixer.h b/nageru/audio_mixer.h
index de6ff54..9dc5c89 100644
--- a/nageru/audio_mixer.h
+++ b/nageru/audio_mixer.h
@@ -41,6 +41,11 @@ struct AudioFormat;
 // Assumes little-endian and chunky, signed PCM throughout.
 std::vector<int32_t> convert_audio_to_fixed32(const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, unsigned num_destination_channels);
 
+// Similar, except converts ot floating-point instead, and converts only one channel.
+void convert_audio_to_fp32(float *dst, size_t out_channel, size_t out_num_channels,
+                           const uint8_t *src, size_t in_channel, bmusb::AudioFormat in_audio_format,
+                           size_t num_samples);
+
 enum EQBand {
 	EQ_BAND_BASS = 0,
 	EQ_BAND_MID,