From 089ff9d73b882c021b64c4fbb8dc49870249b4c2 Mon Sep 17 00:00:00 2001
From: Paul Adenot <paul@paul.cx>
Date: Tue, 1 Sep 2015 14:25:48 +0200
Subject: [PATCH] Bug 901633 - Part 12 - Add a function to deinterleave and
 convert an audio buffer. r=jesup

--HG--
extra : rebase_source : 60200bdecfb896d17cf42f205aba2f08afe2e4ac
---
 dom/media/AudioSampleFormat.h | 45 +++++++++++++++++++++++++++++++++++
 dom/media/AudioSegment.h      | 26 ++++++++++++++++----
 2 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/dom/media/AudioSampleFormat.h b/dom/media/AudioSampleFormat.h
index 2ea986518b46c..5ce98d3ad0233 100644
--- a/dom/media/AudioSampleFormat.h
+++ b/dom/media/AudioSampleFormat.h
@@ -96,6 +96,51 @@ FloatToAudioSample<int16_t>(float aValue)
   return int16_t(clamped);
 }
 
+template <typename T> T IntegerToAudioSample(int16_t aValue);
+
+template <> inline float
+IntegerToAudioSample<float>(int16_t aValue)
+{
+  return aValue / 32768.0f;
+}
+template <> inline int16_t
+IntegerToAudioSample<int16_t>(int16_t aValue)
+{
+  return aValue;
+}
+
+template<typename SrcT, typename DstT>
+inline void
+ConvertAudioSample(SrcT aIn, DstT& aOut);
+
+template<>
+inline void
+ConvertAudioSample(int16_t aIn, int16_t & aOut)
+{
+  aOut = aIn;
+}
+
+template<>
+inline void
+ConvertAudioSample(int16_t aIn, float& aOut)
+{
+  aOut = AudioSampleToFloat(aIn);
+}
+
+template<>
+inline void
+ConvertAudioSample(float aIn, float& aOut)
+{
+  aOut = aIn;
+}
+
+template<>
+inline void
+ConvertAudioSample(float aIn, int16_t& aOut)
+{
+  aOut = FloatToAudioSample<int16_t>(aIn);
+}
+
 // Sample buffer conversion
 
 template <typename From, typename To> inline void
diff --git a/dom/media/AudioSegment.h b/dom/media/AudioSegment.h
index 90b2750527fc1..9bfb4f1185cde 100644
--- a/dom/media/AudioSegment.h
+++ b/dom/media/AudioSegment.h
@@ -57,16 +57,16 @@ const int GUESS_AUDIO_CHANNELS = 2;
 const uint32_t WEBAUDIO_BLOCK_SIZE_BITS = 7;
 const uint32_t WEBAUDIO_BLOCK_SIZE = 1 << WEBAUDIO_BLOCK_SIZE_BITS;
 
-template <class SrcT, class DestT>
+template <typename SrcT, typename DestT>
 static void
 InterleaveAndConvertBuffer(const SrcT* const* aSourceChannels,
-                           int32_t aLength, float aVolume,
-                           int32_t aChannels,
+                           uint32_t aLength, float aVolume,
+                           uint32_t aChannels,
                            DestT* aOutput)
 {
   DestT* output = aOutput;
-  for (int32_t i = 0; i < aLength; ++i) {
-    for (int32_t channel = 0; channel < aChannels; ++channel) {
+  for (size_t i = 0; i < aLength; ++i) {
+    for (size_t channel = 0; channel < aChannels; ++channel) {
       float v = AudioSampleToFloat(aSourceChannels[channel][i])*aVolume;
       *output = FloatToAudioSample<DestT>(v);
       ++output;
@@ -74,6 +74,22 @@ InterleaveAndConvertBuffer(const SrcT* const* aSourceChannels,
   }
 }
 
+template <typename SrcT, typename DestT>
+static void
+DeinterleaveAndConvertBuffer(const SrcT* aSourceBuffer,
+                             uint32_t aFrames, uint32_t aChannels,
+                             DestT** aOutput)
+{
+  for (size_t i = 0; i < aChannels; i++) {
+    size_t interleavedIndex = i;
+    for (size_t j = 0; j < aFrames; j++) {
+      ConvertAudioSample(aSourceBuffer[interleavedIndex],
+                         aOutput[i][j]);
+      interleavedIndex += aChannels;
+    }
+  }
+}
+
 class SilentChannel
 {
 public: