Bug 851530: Part 1 - Added support for decoding uLaw and aLaw enconded wave files. r=jya

--HG--
extra : rebase_source : f9179aa998afb3bf6b7c3a2ef2b841aded6c1153

dom/media/DecoderTraits.cpp

@@ -134,8 +134,10 @@ static const char* const gWaveTypes[5] = {
   nullptr
 };
 
-static char const *const gWaveCodecs[2] = {
+static char const *const gWaveCodecs[4] = {
   "1", // Microsoft PCM Format
+  "6", // aLaw Encoding
+  "7", // uLaw Encoding
   nullptr
 };
 

dom/media/platforms/agnostic/WAVDecoder.cpp

@@ -12,6 +12,39 @@ using mp4_demuxer::ByteReader;
 
 namespace mozilla {
 
+int16_t
+DecodeALawSample(uint8_t aValue)
+{
+  aValue = aValue ^ 0x55;
+  int8_t sign = (aValue & 0x80) ? -1 : 1;
+  uint8_t exponent = (aValue & 0x70) >> 4;
+  uint8_t mantissa = aValue & 0x0F;
+  int16_t sample = mantissa << 4;
+  switch (exponent) {
+    case 0:
+      sample += 8;
+      break;
+    case 1:
+      sample += 0x108;
+      break;
+    default:
+      sample += 0x108;
+      sample <<= exponent - 1;
+  }
+  return sign * sample;
+}
+
+int16_t
+DecodeULawSample(uint8_t aValue)
+{
+  aValue = aValue ^ 0xFF;
+  int8_t sign = (aValue & 0x80) ? -1 : 1;
+  uint8_t exponent = (aValue & 0x70) >> 4;
+  uint8_t mantissa = aValue & 0x0F;
+  int16_t sample = (33 + 2 * mantissa) * (2 << (exponent + 1)) - 33;
+  return sign * sample;
+}
+
 WaveDataDecoder::WaveDataDecoder(const AudioInfo& aConfig,
                                  FlushableTaskQueue* aTaskQueue,
                                  MediaDataDecoderCallback* aCallback)
@@ -69,18 +102,30 @@ WaveDataDecoder::DoDecode(MediaRawData* aSample)
   auto buffer = MakeUnique<AudioDataValue[]>(frames * mInfo.mChannels);
   for (int i = 0; i < frames; ++i) {
     for (unsigned int j = 0; j < mInfo.mChannels; ++j) {
-      if (mInfo.mBitDepth == 8) {
+      if (mInfo.mProfile == 6) {                              //ALAW Data
         uint8_t v = aReader.ReadU8();
+        int16_t decoded = DecodeALawSample(v);
         buffer[i * mInfo.mChannels + j] =
-            UInt8bitToAudioSample<AudioDataValue>(v);
-      } else if (mInfo.mBitDepth == 16) {
-        int16_t v = aReader.ReadLE16();
+            IntegerToAudioSample<AudioDataValue>(decoded);
+      } else if (mInfo.mProfile == 7) {                       //ULAW Data
+        uint8_t v = aReader.ReadU8();
+        int16_t decoded = DecodeULawSample(v);
         buffer[i * mInfo.mChannels + j] =
-            IntegerToAudioSample<AudioDataValue>(v);
-      } else if (mInfo.mBitDepth == 24) {
-        int32_t v = aReader.ReadLE24();
-        buffer[i * mInfo.mChannels + j] =
-            Int24bitToAudioSample<AudioDataValue>(v);
+            IntegerToAudioSample<AudioDataValue>(decoded);
+      } else {                                                //PCM Data
+        if (mInfo.mBitDepth == 8) {
+          uint8_t v = aReader.ReadU8();
+          buffer[i * mInfo.mChannels + j] =
+              UInt8bitToAudioSample<AudioDataValue>(v);
+        } else if (mInfo.mBitDepth == 16) {
+          int16_t v = aReader.ReadLE16();
+          buffer[i * mInfo.mChannels + j] =
+              IntegerToAudioSample<AudioDataValue>(v);
+        } else if (mInfo.mBitDepth == 24) {
+          int32_t v = aReader.ReadLE24();
+          buffer[i * mInfo.mChannels + j] =
+              Int24bitToAudioSample<AudioDataValue>(v);
+        }
       }
     }
   }
@@ -132,6 +177,8 @@ WaveDataDecoder::IsWave(const nsACString& aMimeType)
   // WAVdemuxer uses "audio/wave; codecs=aNum".
   return aMimeType.EqualsLiteral("audio/x-wav") ||
          aMimeType.EqualsLiteral("audio/wave; codecs=1") ||
+         aMimeType.EqualsLiteral("audio/wave; codecs=6") ||
+         aMimeType.EqualsLiteral("audio/wave; codecs=7") ||
          aMimeType.EqualsLiteral("audio/wave; codecs=65534");
 }
 

dom/media/platforms/android/AndroidDecoderModule.cpp

@@ -263,6 +263,8 @@ AndroidDecoderModule::SupportsMimeType(const nsACString& aMimeType) const
   // To avoid this we check for wav types here.
   if (aMimeType.EqualsLiteral("audio/x-wav") ||
       aMimeType.EqualsLiteral("audio/wave; codecs=1") ||
+      aMimeType.EqualsLiteral("audio/wave; codecs=6") ||
+      aMimeType.EqualsLiteral("audio/wave; codecs=7") ||
       aMimeType.EqualsLiteral("audio/wave; codecs=65534")) {
     return false;
   }  

dom/media/wave/WaveDecoder.cpp

@@ -52,7 +52,10 @@ WaveDecoder::CanHandleMediaType(const nsACString& aType,
 {
   if (aType.EqualsASCII("audio/wave") || aType.EqualsASCII("audio/x-wav") ||
       aType.EqualsASCII("audio/wav")  || aType.EqualsASCII("audio/x-pn-wav")) {
-    return IsEnabled() && (aCodecs.IsEmpty() || aCodecs.EqualsASCII("1"));
+    return IsEnabled() && (aCodecs.IsEmpty() ||
+                           aCodecs.EqualsASCII("1") ||
+                           aCodecs.EqualsASCII("6") ||
+                           aCodecs.EqualsASCII("7"));
   }
 
   return false;