Bug 1321164 - part2 : use enum for NAL types. r=jya

In order to increase the readability, use enum value for the NAL types.

MozReview-Commit-ID: 8iwFbB7BEOM

--HG--
extra : rebase_source : 4bfecd012904942f6ad38be9b6b69786d2d732d1

media/libstagefright/binding/H264.cpp

@@ -151,10 +151,12 @@ H264::DecodeNALUnit(const mozilla::MediaByteBuffer* aNAL)
   ByteReader reader(aNAL);
   uint8_t nal_unit_type = reader.ReadU8() & 0x1f;
   uint32_t nalUnitHeaderBytes = 1;
-  if (nal_unit_type == 14 || nal_unit_type == 20 || nal_unit_type == 21) {
+  if (nal_unit_type == H264_NAL_PREFIX ||
+      nal_unit_type == H264_NAL_SLICE_EXT ||
+      nal_unit_type == H264_NAL_SLICE_EXT_DVC) {
     bool svc_extension_flag = false;
     bool avc_3d_extension_flag = false;
-    if (nal_unit_type != 21) {
+    if (nal_unit_type != H264_NAL_SLICE_EXT_DVC) {
       svc_extension_flag = reader.PeekU8() & 0x80;
     } else {
       avc_3d_extension_flag = reader.PeekU8() & 0x80;
@@ -576,7 +578,7 @@ H264::DecodeSPSDataSetFromExtraData(const mozilla::MediaByteBuffer* aExtraData,
   for (uint32_t idx = 0; idx < numSps; idx++) {
     uint16_t length = reader.ReadU16();
 
-    if ((reader.PeekU8() & 0x1f) != 7) {
+    if ((reader.PeekU8() & 0x1f) != H264_NAL_SPS) {
       // Not a SPS NAL type.
       return false;
     }
@@ -647,7 +649,7 @@ H264::DecodePPSDataSetFromExtraData(const mozilla::MediaByteBuffer* aExtraData,
   for (uint8_t i = 0; i < numSps; i++) {
     uint16_t length = reader.ReadU16();
 
-    if ((reader.PeekU8() & 0x1f) != 7) {
+    if ((reader.PeekU8() & 0x1f) != H264_NAL_SPS) {
       // Not a SPS NAL type.
       return false;
     }
@@ -666,7 +668,7 @@ H264::DecodePPSDataSetFromExtraData(const mozilla::MediaByteBuffer* aExtraData,
   for (uint32_t idx = 0; idx < numPps; idx++) {
     uint16_t length = reader.ReadU16();
 
-    if ((reader.PeekU8() & 0x1f) != 8) {
+    if ((reader.PeekU8() & 0x1f) != H264_NAL_PPS) {
       // Not a PPS NAL type.
       return false;
     }
@@ -881,7 +883,7 @@ H264::GetFrameType(const mozilla::MediaRawData* aSample)
     if (!p) {
       return FrameType::INVALID;
     }
-    if ((p[0] & 0x1f) == 5) {
+    if ((p[0] & 0x1f) == H264_NAL_IDR_SLICE) {
       // IDR NAL.
       return FrameType::I_FRAME;
     }

media/libstagefright/binding/include/mp4_demuxer/H264.h

@@ -13,6 +13,27 @@ namespace mp4_demuxer {
 #define MAX_SPS_COUNT 32
 #define MAX_PPS_COUNT 256
 
+// NAL unit types
+enum NAL_TYPES {
+    H264_NAL_SLICE           = 1,
+    H264_NAL_DPA             = 2,
+    H264_NAL_DPB             = 3,
+    H264_NAL_DPC             = 4,
+    H264_NAL_IDR_SLICE       = 5,
+    H264_NAL_SEI             = 6,
+    H264_NAL_SPS             = 7,
+    H264_NAL_PPS             = 8,
+    H264_NAL_AUD             = 9,
+    H264_NAL_END_SEQUENCE    = 10,
+    H264_NAL_END_STREAM      = 11,
+    H264_NAL_FILLER_DATA     = 12,
+    H264_NAL_SPS_EXT         = 13,
+    H264_NAL_PREFIX          = 14,
+    H264_NAL_AUXILIARY_SLICE = 19,
+    H264_NAL_SLICE_EXT       = 20,
+    H264_NAL_SLICE_EXT_DVC   = 21,
+};
+
 class BitReader;
 
 struct SPSData