23 files changed, 1189 insertions, 187 deletions

diff --git a/content/common/gpu/media/h264_bit_reader.cc b/content/common/gpu/media/h264_bit_reader.cc
new file mode 100644
index 0000000..b8d00e1
--- /dev/null
+++ b/content/common/gpu/media/h264_bit_reader.cc
@@ -0,0 +1,45 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/common/gpu/media/h264_bit_reader.h"
+
+namespace content {
+
+H264BitReader::H264BitReader() {
+}
+
+H264BitReader::~H264BitReader() {}
+
+void H264BitReader::UpdateCurrByte() {
+  DCHECK_EQ(num_remaining_bits_in_curr_byte_, 0);
+
+  if (bytes_left_ >= 1) {
+    // Emulation prevention three-byte detection.
+    // If a sequence of 0x000003 is found, skip (ignore) the last byte (0x03).
+    if (*data_ == 0x03 && Tell() >= 16 && data_[-1] == 0 && data_[-2] == 0) {
+      // Detected 0x000003, skip last byte.
+      ++data_;
+      --bytes_left_;
+      position_ += 8;
+    }
+  }
+
+  if (bytes_left_ >= 1) {
+    // Load a new byte and advance pointers.
+    curr_byte_ = *data_;
+    ++data_;
+    --bytes_left_;
+    num_remaining_bits_in_curr_byte_ = 8;
+  }
+
+  // Check if this is the end of RBSP data.
+  if (bytes_left_ == 0) {
+    while (num_remaining_bits_in_curr_byte_ != 0 && !(curr_byte_ & 0x1)) {
+      --num_remaining_bits_in_curr_byte_;
+      curr_byte_ >>= 1;
+    }
+  }
+}
+
+}  // namespace content
diff --git a/content/common/gpu/media/h264_bit_reader.h b/content/common/gpu/media/h264_bit_reader.h
new file mode 100644
index 0000000..652c869
--- /dev/null
+++ b/content/common/gpu/media/h264_bit_reader.h
@@ -0,0 +1,31 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_COMMON_GPU_MEDIA_H264_BIT_READER_H_
+#define CONTENT_COMMON_GPU_MEDIA_H264_BIT_READER_H_
+
+#include "base/compiler_specific.h"
+#include "media/base/bit_reader.h"
+
+namespace content {
+
+// A class to provide bit-granularity reading of H.264 streams.
+// This class takes into account H.264 stream-specific constraints, such as
+// skipping emulation-prevention bytes and stop bits. See spec for more
+// details.
+class H264BitReader : public media::BitReader {
+ public:
+  H264BitReader();
+  virtual ~H264BitReader();
+
+ private:
+  // This function handles the H.264 escape sequence and stop bit.
+  virtual void UpdateCurrByte() OVERRIDE;
+
+  DISALLOW_COPY_AND_ASSIGN(H264BitReader);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_H264_BIT_READER_H_
diff --git a/content/common/gpu/media/h264_bit_reader_unittest.cc b/content/common/gpu/media/h264_bit_reader_unittest.cc
new file mode 100644
index 0000000..cf90e02
--- /dev/null
+++ b/content/common/gpu/media/h264_bit_reader_unittest.cc
@@ -0,0 +1,68 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/common/gpu/media/h264_bit_reader.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+using content::H264BitReader;
+
+TEST(BitReaderTest, H264StreamTest) {
+  // This stream contains an escape sequence. Its last byte only has 4 bits.
+  // 0001 0010 0011 0100 0000 0000 0000 0000 0000 0011 0101 0110 0111 0000
+  uint8 buffer[] = {0x12, 0x34, 0x00, 0x00, 0x03, 0x56, 0x70};
+  H264BitReader reader;
+  uint8 value8;
+  uint32 value32;
+
+  reader.Initialize(buffer, sizeof(buffer));
+  EXPECT_EQ(reader.Tell(), 0);
+  EXPECT_TRUE(reader.ReadBits(4, &value8));
+  EXPECT_EQ(value8, 1u);
+  EXPECT_EQ(reader.Tell(), 4);
+  EXPECT_TRUE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.ReadBits(8, &value8));
+  EXPECT_EQ(value8, 0x23u);
+  EXPECT_EQ(reader.Tell(), 12);
+  EXPECT_TRUE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.ReadBits(24, &value32));
+  EXPECT_EQ(value32, 0x400005u);
+  EXPECT_EQ(reader.Tell(), 44);  // Include the skipped escape byte
+  EXPECT_TRUE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.ReadBits(8, &value8));
+  EXPECT_EQ(value8, 0x67u);
+  EXPECT_EQ(reader.Tell(), 52);  // Include the skipped escape byte
+  EXPECT_FALSE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.ReadBits(0, &value8));
+  EXPECT_EQ(reader.Tell(), 52);  // Include the skipped escape byte
+  EXPECT_FALSE(reader.ReadBits(1, &value8));
+  EXPECT_FALSE(reader.HasMoreData());
+
+  // Do it again using SkipBits
+  reader.Initialize(buffer, sizeof(buffer));
+  EXPECT_EQ(reader.Tell(), 0);
+  EXPECT_TRUE(reader.SkipBits(4));
+  EXPECT_EQ(reader.Tell(), 4);
+  EXPECT_TRUE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.SkipBits(8));
+  EXPECT_EQ(reader.Tell(), 12);
+  EXPECT_TRUE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.SkipBits(24));
+  EXPECT_EQ(reader.Tell(), 44);  // Include the skipped escape byte
+  EXPECT_TRUE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.SkipBits(8));
+  EXPECT_EQ(reader.Tell(), 52);  // Include the skipped escape byte
+  EXPECT_FALSE(reader.HasMoreData());
+
+  EXPECT_TRUE(reader.SkipBits(0));
+  EXPECT_FALSE(reader.SkipBits(1));
+  EXPECT_FALSE(reader.HasMoreData());
+}
diff --git a/content/common/gpu/media/h264_parser.cc b/content/common/gpu/media/h264_parser.cc
index ace3dab..1452238 100644
--- a/content/common/gpu/media/h264_parser.cc
+++ b/content/common/gpu/media/h264_parser.cc
@@ -50,103 +50,6 @@ H264SEIMessage::H264SEIMessage() {
   memset(this, 0, sizeof(*this));
 }
 
-H264Parser::H264BitReader::H264BitReader()
-    : data_(NULL),
-      bytes_left_(0),
-      curr_byte_(0),
-      num_remaining_bits_in_curr_byte_(0),
-      prev_two_bytes_(0) {
-}
-
-H264Parser::H264BitReader::~H264BitReader() {}
-
-bool H264Parser::H264BitReader::Initialize(const uint8* data, off_t size) {
-  DCHECK(data);
-
-  if (size < 1)
-    return false;
-
-  data_ = data;
-  bytes_left_ = size;
-  num_remaining_bits_in_curr_byte_ = 0;
-  // Initially set to 0xffff to accept all initial two-byte sequences.
-  prev_two_bytes_ = 0xffff;
-
-  return true;
-}
-
-bool H264Parser::H264BitReader::UpdateCurrByte() {
-  if (bytes_left_ < 1)
-    return false;
-
-  // Emulation prevention three-byte detection.
-  // If a sequence of 0x000003 is found, skip (ignore) the last byte (0x03).
-  if (*data_ == 0x03 && (prev_two_bytes_ & 0xffff) == 0) {
-    // Detected 0x000003, skip last byte.
-    ++data_;
-    --bytes_left_;
-    // Need another full three bytes before we can detect the sequence again.
-    prev_two_bytes_ = 0xffff;
-
-    if (bytes_left_ < 1)
-      return false;
-  }
-
-  // Load a new byte and advance pointers.
-  curr_byte_ = *data_++ & 0xff;
-  --bytes_left_;
-  num_remaining_bits_in_curr_byte_ = 8;
-
-  prev_two_bytes_ = (prev_two_bytes_ << 8) | curr_byte_;
-
-  return true;
-}
-
-// Read |num_bits| (1 to 31 inclusive) from the stream and return them
-// in |out|, with first bit in the stream as MSB in |out| at position
-// (|num_bits| - 1).
-bool H264Parser::H264BitReader::ReadBits(int num_bits, int *out) {
-  int bits_left = num_bits;
-  *out = 0;
-  DCHECK(num_bits <= 31);
-
-  while (num_remaining_bits_in_curr_byte_ < bits_left) {
-    // Take all that's left in current byte, shift to make space for the rest.
-    *out = (curr_byte_ << (bits_left - num_remaining_bits_in_curr_byte_));
-    bits_left -= num_remaining_bits_in_curr_byte_;
-
-    if (!UpdateCurrByte())
-      return false;
-  }
-
-  *out |= (curr_byte_ >> (num_remaining_bits_in_curr_byte_ - bits_left));
-  *out &= ((1 << num_bits) - 1);
-  num_remaining_bits_in_curr_byte_ -= bits_left;
-
-  return true;
-}
-
-off_t H264Parser::H264BitReader::NumBitsLeft() {
-  return (num_remaining_bits_in_curr_byte_ + bytes_left_ * 8);
-}
-
-bool H264Parser::H264BitReader::HasMoreRBSPData() {
-  // Make sure we have more bits, if we are at 0 bits in current byte
-  // and updating current byte fails, we don't have more data anyway.
-  if (num_remaining_bits_in_curr_byte_ == 0 && !UpdateCurrByte())
-      return false;
-
-  // On last byte?
-  if (bytes_left_)
-    return true;
-
-  // Last byte, look for stop bit;
-  // We have more RBSP data if the last non-zero bit we find is not the
-  // first available bit.
-  return (curr_byte_ &
-          ((1 << (num_remaining_bits_in_curr_byte_ - 1)) - 1)) != 0;
-}
-
 #define READ_BITS_OR_RETURN(num_bits, out)                                    \
 do {                                                                          \
   int _out;                                                                   \
@@ -358,7 +261,9 @@ H264Parser::Result H264Parser::AdvanceToNextNALU(H264NALU *nalu) {
   nalu->data = stream_ + off_to_nalu_start;
 
   // Initialize bit reader at the start of found NALU.
-  if (!br_.Initialize(nalu->data, nalu->size))
+  br_.Initialize(nalu->data, nalu->size);
+
+  if (!br_.HasMoreData())
     return kEOStream;
 
   DVLOG(4) << "Looking for NALU, Stream bytes left: " << bytes_left_
@@ -812,7 +717,7 @@ H264Parser::Result H264Parser::ParsePPS(int* pps_id) {
   READ_BOOL_OR_RETURN(&pps->constrained_intra_pred_flag);
   READ_BOOL_OR_RETURN(&pps->redundant_pic_cnt_present_flag);
 
-  if (br_.HasMoreRBSPData()) {
+  if (br_.HasMoreData()) {
     READ_BOOL_OR_RETURN(&pps->transform_8x8_mode_flag);
     READ_BOOL_OR_RETURN(&pps->pic_scaling_matrix_present_flag);
 
diff --git a/content/common/gpu/media/h264_parser.h b/content/common/gpu/media/h264_parser.h
index ed76f16..e9aea18 100644
--- a/content/common/gpu/media/h264_parser.h
+++ b/content/common/gpu/media/h264_parser.h
@@ -13,6 +13,7 @@
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
+#include "content/common/gpu/media/h264_bit_reader.h"
 
 namespace content {
 
@@ -301,61 +302,6 @@ class CONTENT_EXPORT H264Parser {
   Result ParseSEI(H264SEIMessage* sei_msg);
 
  private:
-  // A class to provide bit-granularity reading of H.264 streams.
-  // This is not a generic bit reader class, as it takes into account
-  // H.264 stream-specific constraints, such as skipping emulation-prevention
-  // bytes and stop bits. See spec for more details.
-  // TODO(posciak): need separate unittests for this class.
-  class H264BitReader {
-   public:
-    H264BitReader();
-    ~H264BitReader();
-
-    // Initialize the reader to start reading at |data|, |size| being size
-    // of |data| in bytes.
-    // Return false on insufficient size of stream..
-    // TODO(posciak,fischman): consider replacing Initialize() with
-    // heap-allocating and creating bit readers on demand instead.
-    bool Initialize(const uint8* data, off_t size);
-
-    // Read |num_bits| next bits from stream and return in |*out|, first bit
-    // from the stream starting at |num_bits| position in |*out|.
-    // |num_bits| may be 1-32, inclusive.
-    // Return false if the given number of bits cannot be read (not enough
-    // bits in the stream), true otherwise.
-    bool ReadBits(int num_bits, int *out);
-
-    // Return the number of bits left in the stream.
-    off_t NumBitsLeft();
-
-    // See the definition of more_rbsp_data() in spec.
-    bool HasMoreRBSPData();
-
-   private:
-    // Advance to the next byte, loading it into curr_byte_.
-    // Return false on end of stream.
-    bool UpdateCurrByte();
-
-    // Pointer to the next unread (not in curr_byte_) byte in the stream.
-    const uint8* data_;
-
-    // Bytes left in the stream (without the curr_byte_).
-    off_t bytes_left_;
-
-    // Contents of the current byte; first unread bit starting at position
-    // 8 - num_remaining_bits_in_curr_byte_ from MSB.
-    int curr_byte_;
-
-    // Number of bits remaining in curr_byte_
-    int num_remaining_bits_in_curr_byte_;
-
-    // Used in emulation prevention three byte detection (see spec).
-    // Initially set to 0xffff to accept all initial two-byte sequences.
-    int prev_two_bytes_;
-
-    DISALLOW_COPY_AND_ASSIGN(H264BitReader);
-  };
-
   // Exp-Golomb code parsing as specified in chapter 9.1 of the spec.
   // Read one unsigned exp-Golomb code from the stream and return in |*val|.
   Result ReadUE(int* val);
diff --git a/content/content_common.gypi b/content/content_common.gypi
index cb1860f..ae14818 100644
--- a/content/content_common.gypi
+++ b/content/content_common.gypi
@@ -216,6 +216,8 @@
     'common/gpu/image_transport_surface_win.cc',
     'common/gpu/media/avc_config_record_builder.cc',
     'common/gpu/media/avc_config_record_builder.h',
+    'common/gpu/media/h264_bit_reader.cc',
+    'common/gpu/media/h264_bit_reader.h',
     'common/gpu/media/h264_parser.cc',
     'common/gpu/media/h264_parser.h',
     'common/gpu/media/mac_video_decode_accelerator.h',
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index eeb3805..ec33b24 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -645,6 +645,7 @@
             '../testing/gtest.gyp:gtest',
           ],
           'sources': [
+            'common/gpu/media/h264_bit_reader_unittest.cc',
             'common/gpu/media/h264_parser_unittest.cc',
           ],
         }
diff --git a/media/base/bit_reader.cc b/media/base/bit_reader.cc
new file mode 100644
index 0000000..e4106fa
--- /dev/null
+++ b/media/base/bit_reader.cc
@@ -0,0 +1,74 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/bit_reader.h"
+
+namespace media {
+
+BitReader::BitReader()
+    : data_(NULL),
+      bytes_left_(0),
+      position_(0),
+      curr_byte_(0),
+      num_remaining_bits_in_curr_byte_(0) {
+}
+
+BitReader::BitReader(const uint8* data, off_t size) {
+  Initialize(data, size);
+}
+
+BitReader::~BitReader() {}
+
+void BitReader::Initialize(const uint8* data, off_t size) {
+  DCHECK(data != NULL || size == 0);  // Data cannot be NULL if size is not 0.
+
+  data_ = data;
+  bytes_left_ = size;
+  position_ = 0;
+  num_remaining_bits_in_curr_byte_ = 0;
+
+  UpdateCurrByte();
+}
+
+void BitReader::UpdateCurrByte() {
+  DCHECK_EQ(num_remaining_bits_in_curr_byte_, 0);
+
+  if (bytes_left_ < 1)
+    return;
+
+  // Load a new byte and advance pointers.
+  curr_byte_ = *data_;
+  ++data_;
+  --bytes_left_;
+  num_remaining_bits_in_curr_byte_ = 8;
+}
+
+bool BitReader::SkipBits(int num_bits) {
+  int dummy;
+  const int kDummySize = static_cast<int>(sizeof(dummy)) * 8;
+
+  while (num_bits > kDummySize) {
+    if (ReadBits(kDummySize, &dummy)) {
+      num_bits -= kDummySize;
+    } else {
+      return false;
+    }
+  }
+
+  return ReadBits(num_bits, &dummy);
+}
+
+off_t BitReader::Tell() const {
+  return position_;
+}
+
+off_t BitReader::NumBitsLeft() const {
+  return (num_remaining_bits_in_curr_byte_ + bytes_left_ * 8);
+}
+
+bool BitReader::HasMoreData() const {
+  return num_remaining_bits_in_curr_byte_ != 0;
+}
+
+}  // namespace media
diff --git a/media/base/bit_reader.h b/media/base/bit_reader.h
new file mode 100644
index 0000000..35c62a9
--- /dev/null
+++ b/media/base/bit_reader.h
@@ -0,0 +1,110 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_BIT_READER_H_
+#define MEDIA_BASE_BIT_READER_H_
+
+#include <sys/types.h>
+#include <algorithm>
+#include <climits>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "media/base/media_export.h"
+
+
+namespace media {
+
+// A class to read bit streams.
+// Classes inherited this class can override its UpdateCurrByte function
+// to support specific escape mechanism, which is widely used by streaming
+// formats like H.264 Annex B.
+class MEDIA_EXPORT BitReader {
+ public:
+  BitReader();
+  BitReader(const uint8* data, off_t size);
+  virtual ~BitReader();
+
+  // Initialize the reader to start reading at |data|, |size| being size
+  // of |data| in bytes.
+  void Initialize(const uint8* data, off_t size);
+
+  // Read |num_bits| next bits from stream and return in |*out|, first bit
+  // from the stream starting at |num_bits| position in |*out|.
+  // |num_bits| cannot be larger than the bits the type can hold.
+  // Return false if the given number of bits cannot be read (not enough
+  // bits in the stream), true otherwise. When return false, the stream will
+  // enter a state where further ReadBits operations will always return false
+  // unless |num_bits| is 0. The type |T| has to be a primitive integer type.
+  template<typename T>
+  bool ReadBits(int num_bits, T *out) {
+    DCHECK(num_bits <= static_cast<int>(sizeof(T) * CHAR_BIT));
+
+    *out = 0;
+    position_ += num_bits;
+
+    while (num_remaining_bits_in_curr_byte_ != 0 && num_bits != 0) {
+      int bits_to_take = std::min(num_remaining_bits_in_curr_byte_, num_bits);
+      *out = (*out << bits_to_take) +
+          (curr_byte_ >> (num_remaining_bits_in_curr_byte_ - bits_to_take));
+      num_bits -= bits_to_take;
+      num_remaining_bits_in_curr_byte_ -= bits_to_take;
+      curr_byte_ &= (1 << num_remaining_bits_in_curr_byte_) - 1;
+
+      if (num_remaining_bits_in_curr_byte_ == 0)
+        UpdateCurrByte();
+    }
+
+    if (num_bits == 0)
+      return true;
+
+    *out = 0;
+    num_remaining_bits_in_curr_byte_ = 0;
+    bytes_left_ = 0;
+
+    return false;
+  }
+
+  bool SkipBits(int num_bits);
+
+  // Return the current position in the stream in unit of bit.
+  // This includes the skipped escape bytes if there are any.
+  off_t Tell() const;
+
+  // Return the number of bits left in the stream.
+  // This doesn't take any escape sequence into account.
+  off_t NumBitsLeft() const;
+
+  bool HasMoreData() const;
+
+ protected:
+  // Advance to the next byte, loading it into curr_byte_.
+  // This function can be overridden to support specific escape mechanism.
+  // If the num_remaining_bits_in_curr_byte_ is 0 after this function returns,
+  // the stream has reached the end.
+  virtual void UpdateCurrByte();
+
+  // Pointer to the next unread (not in curr_byte_) byte in the stream.
+  const uint8* data_;
+
+  // Bytes left in the stream (without the curr_byte_).
+  off_t bytes_left_;
+
+  // Current position in bits.
+  off_t position_;
+
+  // Contents of the current byte; first unread bit starting at position
+  // 8 - num_remaining_bits_in_curr_byte_ from MSB.
+  uint8 curr_byte_;
+
+  // Number of bits remaining in curr_byte_
+  int num_remaining_bits_in_curr_byte_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BitReader);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_BIT_READER_H_
diff --git a/media/base/bit_reader_unittest.cc b/media/base/bit_reader_unittest.cc
new file mode 100644
index 0000000..00d425f
--- /dev/null
+++ b/media/base/bit_reader_unittest.cc
@@ -0,0 +1,110 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/bit_reader.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace media {
+
+TEST(BitReaderTest, EmptyStreamTest) {
+  BitReader reader(NULL, 0);
+  uint8 value8 = 0xff;
+
+  ASSERT_FALSE(reader.HasMoreData());
+  ASSERT_EQ(reader.Tell(), 0);
+  ASSERT_TRUE(reader.ReadBits(0, &value8));
+  ASSERT_TRUE(reader.SkipBits(0));
+  ASSERT_EQ(reader.Tell(), 0);
+  ASSERT_FALSE(reader.HasMoreData());
+  ASSERT_FALSE(reader.ReadBits(1, &value8));
+  ASSERT_FALSE(reader.SkipBits(1));
+  ASSERT_EQ(value8, 0);
+}
+
+TEST(BitReaderTest, NormalOperationTest) {
+  // 0101 0101 1001 1001 repeats 4 times
+  uint8 buffer[] = {0x55, 0x99, 0x55, 0x99, 0x55, 0x99, 0x55, 0x99};
+  BitReader reader(buffer, 6);  // Initialize with 6 bytes only
+  uint8 value8;
+  uint64 value64;
+
+  ASSERT_TRUE(reader.HasMoreData());
+  ASSERT_EQ(reader.Tell(), 0);
+  ASSERT_TRUE(reader.ReadBits(1, &value8));
+  ASSERT_EQ(value8, 0);
+  ASSERT_TRUE(reader.ReadBits(8, &value8));
+  ASSERT_EQ(value8, 0xab);  // 1010 1011
+  ASSERT_EQ(reader.Tell(), 9);
+  ASSERT_TRUE(reader.HasMoreData());
+  ASSERT_TRUE(reader.SkipBits(7));
+  ASSERT_EQ(reader.Tell(), 16);
+  ASSERT_TRUE(reader.ReadBits(32, &value64));
+  ASSERT_EQ(value64, 0x55995599u);
+  ASSERT_EQ(reader.Tell(), 48);
+  ASSERT_FALSE(reader.HasMoreData());
+  ASSERT_FALSE(reader.SkipBits(1));
+  ASSERT_FALSE(reader.ReadBits(1, &value8));
+  ASSERT_TRUE(reader.SkipBits(0));
+  value8 = 0xff;
+  ASSERT_TRUE(reader.ReadBits(0, &value8));
+  ASSERT_EQ(value8, 0);
+
+  reader.Initialize(buffer, 8);
+  ASSERT_TRUE(reader.ReadBits(64, &value64));
+  EXPECT_EQ(value64, 0x5599559955995599ull);
+  EXPECT_FALSE(reader.HasMoreData());
+  EXPECT_EQ(reader.Tell(), 64);
+  EXPECT_FALSE(reader.ReadBits(1, &value8));
+  EXPECT_FALSE(reader.SkipBits(1));
+  EXPECT_TRUE(reader.ReadBits(0, &value8));
+  EXPECT_TRUE(reader.SkipBits(0));
+}
+
+TEST(BitReaderTest, LongSkipTest) {
+  uint8 buffer[] = {
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 1
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 2
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 3
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 4
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 5
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 6
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 7
+    0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78,  // 64 * 8
+    0x87, 0x65
+  };
+  BitReader reader(buffer, sizeof(buffer));
+  uint8 value8;
+
+  EXPECT_TRUE(reader.SkipBits(64 * 8 + 8));
+  EXPECT_EQ(reader.Tell(), 64 * 8 + 8);
+  EXPECT_TRUE(reader.ReadBits(8, &value8));
+  EXPECT_EQ(value8, 0x65);
+  EXPECT_EQ(reader.Tell(), 64 * 8 + 16);
+  EXPECT_FALSE(reader.HasMoreData());
+  EXPECT_EQ(reader.NumBitsLeft(), 0);
+}
+
+TEST(BitReaderTest, ReadBeyondEndTest) {
+  uint8 buffer[] = {0x12};
+  BitReader reader(buffer, sizeof(buffer));
+  uint8 value8;
+
+  EXPECT_TRUE(reader.SkipBits(4));
+  EXPECT_FALSE(reader.ReadBits(5, &value8));
+  EXPECT_FALSE(reader.ReadBits(1, &value8));
+  EXPECT_FALSE(reader.SkipBits(1));
+  EXPECT_TRUE(reader.ReadBits(0, &value8));
+  EXPECT_TRUE(reader.SkipBits(0));
+
+  reader.Initialize(buffer, sizeof(buffer));
+  EXPECT_TRUE(reader.SkipBits(4));
+  EXPECT_FALSE(reader.SkipBits(5));
+  EXPECT_FALSE(reader.ReadBits(1, &value8));
+  EXPECT_FALSE(reader.SkipBits(1));
+  EXPECT_TRUE(reader.ReadBits(0, &value8));
+  EXPECT_TRUE(reader.SkipBits(0));
+}
+
+}  // namespace media
diff --git a/media/media.gyp b/media/media.gyp
index 29300fe..c73c314 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -133,6 +133,8 @@
         'base/audio_renderer_mixer.h',
         'base/audio_renderer_mixer_input.cc',
         'base/audio_renderer_mixer_input.h',
+        'base/bit_reader.cc',
+        'base/bit_reader.h',
         'base/bitstream_buffer.h',
         'base/buffers.cc',
         'base/buffers.h',
@@ -452,6 +454,8 @@
         }],
         ['proprietary_codecs==1 or branding=="Chrome"', {
           'sources': [
+            'mp4/aac.cc',
+            'mp4/aac.h',
             'mp4/avc.cc',
             'mp4/avc.h',
             'mp4/box_definitions.cc',
@@ -460,6 +464,8 @@
             'mp4/box_reader.h',
             'mp4/cenc.cc',
             'mp4/cenc.h',
+            'mp4/es_descriptor.cc',
+            'mp4/es_descriptor.h',
             'mp4/mp4_stream_parser.cc',
             'mp4/mp4_stream_parser.h',
             'mp4/offset_byte_queue.cc',
@@ -665,6 +671,7 @@
         'audio/win/audio_output_win_unittest.cc',
         'base/audio_renderer_mixer_unittest.cc',
         'base/audio_renderer_mixer_input_unittest.cc',
+        'base/bit_reader_unittest.cc',
         'base/buffers_unittest.cc',
         'base/clock_unittest.cc',
         'base/composite_filter_unittest.cc',
@@ -762,8 +769,10 @@
         }],
         ['proprietary_codecs==1 or branding=="Chrome"', {
           'sources': [
+            'mp4/aac_unittest.cc',
             'mp4/avc_unittest.cc',
             'mp4/box_reader_unittest.cc',
+            'mp4/es_descriptor_unittest.cc',
             'mp4/mp4_stream_parser_unittest.cc',
             'mp4/offset_byte_queue_unittest.cc',
           ],
diff --git a/media/mp4/aac.cc b/media/mp4/aac.cc
new file mode 100644
index 0000000..e79e927
--- /dev/null
+++ b/media/mp4/aac.cc
@@ -0,0 +1,252 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/mp4/aac.h"
+
+#include "base/logging.h"
+#include "media/base/bit_reader.h"
+#include "media/mp4/rcheck.h"
+
+// The following conversion table is extracted from ISO 14496 Part 3 -
+// Table 1.16 - Sampling Frequency Index.
+static const uint32 kFrequencyMap[] = {
+  96000, 88200, 64000, 48000, 44100, 32000, 24000,
+  22050, 16000, 12000, 11025, 8000, 7350
+};
+
+static ChannelLayout GetChannelLayout(uint8 channel_config) {
+  switch (channel_config) {
+    case 1:
+      return CHANNEL_LAYOUT_MONO;
+    case 2:
+      return CHANNEL_LAYOUT_STEREO;
+    case 3:
+      return CHANNEL_LAYOUT_SURROUND;
+    case 4:
+      return CHANNEL_LAYOUT_4_0;
+    case 5:
+      return CHANNEL_LAYOUT_5_0;
+    case 6:
+      return CHANNEL_LAYOUT_5_1;
+    case 8:
+      return CHANNEL_LAYOUT_7_1;
+    default:
+      break;
+  }
+
+  return CHANNEL_LAYOUT_UNSUPPORTED;
+}
+
+namespace media {
+
+namespace mp4 {
+
+AAC::AAC()
+    : profile_(0), frequency_index_(0), channel_config_(0), frequency_(0),
+      channel_layout_(CHANNEL_LAYOUT_UNSUPPORTED) {
+}
+
+AAC::~AAC() {
+}
+
+bool AAC::Parse(const std::vector<uint8>& data) {
+  BitReader reader;
+  uint8 extension_type = 0;
+  bool ps_present = false;
+  uint8 extension_frequency_index;
+
+  profile_ = 0;
+  frequency_index_ = 0;
+  frequency_ = 0;
+  channel_config_ = 0;
+
+  reader.Initialize(&data[0], data.size());
+
+  // The following code is written according to ISO 14496 Part 3 Table 1.13 -
+  // Syntax of AudioSpecificConfig.
+
+  // Read base configuration
+  RCHECK(reader.ReadBits(5, &profile_));
+  RCHECK(reader.ReadBits(4, &frequency_index_));
+  if (frequency_index_ == 0xf)
+    RCHECK(reader.ReadBits(24, &frequency_));
+  RCHECK(reader.ReadBits(4, &channel_config_));
+
+  extension_frequency_index = frequency_index_;
+
+  // Read extension configuration
+  if (profile_ == 5 || profile_ == 29) {
+    ps_present = (profile_ == 29);
+    extension_type = 5;
+    RCHECK(reader.ReadBits(4, &extension_frequency_index));
+    if (extension_frequency_index == 0xf)
+      RCHECK(reader.ReadBits(24, &frequency_));
+    RCHECK(reader.ReadBits(5, &profile_));
+  }
+
+  RCHECK(SkipDecoderGASpecificConfig(&reader));
+  RCHECK(SkipErrorSpecificConfig());
+
+  // Read extension configuration again
+  if (extension_type != 5 && reader.NumBitsLeft() >= 16) {
+    uint16 sync_extension_type;
+    uint8 sbr_present_flag;
+    uint8 ps_present_flag;
+
+    RCHECK(reader.ReadBits(11, &sync_extension_type));
+
+    if (sync_extension_type == 0x2b7) {
+      RCHECK(reader.ReadBits(5, &extension_type));
+
+      if (extension_type == 5) {
+        RCHECK(reader.ReadBits(1, &sbr_present_flag));
+
+        if (sbr_present_flag) {
+          RCHECK(reader.ReadBits(4, &extension_frequency_index));
+
+          if (extension_frequency_index == 0xf)
+            RCHECK(reader.ReadBits(24, &frequency_));
+
+          RCHECK(reader.ReadBits(11, &sync_extension_type));
+
+          if (sync_extension_type == 0x548) {
+            RCHECK(reader.ReadBits(1, &ps_present_flag));
+            ps_present = ps_present_flag != 0;
+          }
+        }
+      }
+    }
+  }
+
+  if (frequency_ == 0) {
+    RCHECK(extension_frequency_index < arraysize(kFrequencyMap));
+    frequency_ = kFrequencyMap[extension_frequency_index];
+  }
+
+  // When Parametric Stereo is on, mono will be played as stereo.
+  if (ps_present && channel_config_ == 1)
+    channel_layout_ = GetChannelLayout(channel_config_ + 1);
+  else
+    channel_layout_ = GetChannelLayout(channel_config_);
+
+  return frequency_ != 0 && channel_layout_ != CHANNEL_LAYOUT_UNSUPPORTED &&
+      profile_ >= 1 && profile_ <= 4 && frequency_index_ != 0xf &&
+      channel_config_ <= 7;
+}
+
+uint32 AAC::frequency() const {
+  return frequency_;
+}
+
+ChannelLayout AAC::channel_layout() const {
+  return channel_layout_;
+}
+
+bool AAC::ConvertEsdsToADTS(std::vector<uint8>* buffer) const {
+  size_t size = buffer->size() + 7;
+
+  DCHECK(profile_ >= 1 && profile_ <= 4 && frequency_index_ != 0xf &&
+         channel_config_ <= 7);
+
+  // ADTS header uses 13 bits for packet size.
+  if (size > (1 << 13) - 1)
+    return false;
+
+  std::vector<uint8>& adts = *buffer;
+
+  adts.insert(buffer->begin(), 7, 0);
+  adts[0] = 0xff;
+  adts[1] = 0xf1;
+  adts[2] = ((profile_ - 1) << 6) + (frequency_index_ << 2) +
+      (channel_config_ >> 2);
+  adts[3] = ((channel_config_ & 0x3) << 6) + (size >> 11);
+  adts[4] = (size & 0x7ff) >> 3;
+  adts[5] = ((size & 7) << 5) + 0x1f;
+  adts[6] = 0xfc;
+
+  return true;
+}
+
+// Currently this function only support GASpecificConfig defined in
+// ISO 14496 Part 3 Table 4.1 - Syntax of GASpecificConfig()
+bool AAC::SkipDecoderGASpecificConfig(BitReader* bit_reader) const {
+  switch (profile_) {
+    case 1:
+    case 2:
+    case 3:
+    case 4:
+    case 6:
+    case 7:
+    case 17:
+    case 19:
+    case 20:
+    case 21:
+    case 22:
+    case 23:
+      return SkipGASpecificConfig(bit_reader);
+    default:
+      break;
+  }
+
+  return false;
+}
+
+bool AAC::SkipErrorSpecificConfig() const {
+  switch (profile_) {
+    case 17:
+    case 19:
+    case 20:
+    case 21:
+    case 22:
+    case 23:
+    case 24:
+    case 25:
+    case 26:
+    case 27:
+      return false;
+    default:
+      break;
+  }
+
+  return true;
+}
+
+// The following code is written according to ISO 14496 part 3 Table 4.1 -
+// GASpecificConfig.
+bool AAC::SkipGASpecificConfig(BitReader* bit_reader) const {
+  uint8 extension_flag = 0;
+  uint8 depends_on_core_coder;
+
+  RCHECK(bit_reader->SkipBits(1));  // frameLengthFlag
+  RCHECK(bit_reader->ReadBits(1, &depends_on_core_coder));
+  if (depends_on_core_coder == 1)
+    RCHECK(bit_reader->SkipBits(14));  // coreCoderDelay
+
+  RCHECK(bit_reader->ReadBits(1, &extension_flag));
+  RCHECK(channel_config_ != 0);
+
+  if (profile_ == 6 || profile_ == 20)
+    RCHECK(bit_reader->SkipBits(3));
+
+  if (extension_flag) {
+    if (profile_ == 22) {
+      RCHECK(bit_reader->SkipBits(5));
+      RCHECK(bit_reader->SkipBits(11));
+    }
+
+    if (profile_ == 17 || profile_ == 19 || profile_ == 20 || profile_ == 23) {
+      RCHECK(bit_reader->SkipBits(1));
+      RCHECK(bit_reader->SkipBits(1));
+      RCHECK(bit_reader->SkipBits(1));
+    }
+
+    RCHECK(bit_reader->SkipBits(1));
+  }
+
+  return true;
+}
+
+}  // namespace mp4
+
+}  // namespace media
diff --git a/media/mp4/aac.h b/media/mp4/aac.h
new file mode 100644
index 0000000..7a2a3f8
--- /dev/null
+++ b/media/mp4/aac.h
@@ -0,0 +1,67 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_MP4_AAC_H_
+#define MEDIA_MP4_AAC_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "media/base/channel_layout.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class BitReader;
+
+namespace mp4 {
+
+// This class parses the AAC information from decoder specific information
+// embedded in the esds box in an ISO BMFF file.
+// Please refer to ISO 14496 Part 3 Table 1.13 - Syntax of AudioSpecificConfig
+// for more details.
+class MEDIA_EXPORT AAC {
+ public:
+  AAC();
+  ~AAC();
+
+  // Parse the AAC config from the raw binary data embedded in esds box.
+  // The function will parse the data and get the ElementaryStreamDescriptor,
+  // then it will parse the ElementaryStreamDescriptor to get audio stream
+  // configurations.
+  bool Parse(const std::vector<uint8>& data);
+
+  uint32 frequency() const;
+  ChannelLayout channel_layout() const;
+
+  // This function converts a raw AAC frame into an AAC frame with an ADTS
+  // header. On success, the function returns true and stores the converted data
+  // in the buffer. The function returns false on failure and leaves the buffer
+  // unchanged.
+  bool ConvertEsdsToADTS(std::vector<uint8>* buffer) const;
+
+ private:
+  bool SkipDecoderGASpecificConfig(BitReader* bit_reader) const;
+  bool SkipErrorSpecificConfig() const;
+  bool SkipGASpecificConfig(BitReader* bit_reader) const;
+
+  // The following variables store the AAC specific configuration information
+  // that are used to generate the ADTS header.
+  uint8 profile_;
+  uint8 frequency_index_;
+  uint8 channel_config_;
+
+  // The following variables store audio configuration information that
+  // can be used by Chromium. They are based on the AAC specific
+  // configuration but can be overridden by extensions in elementary
+  // stream descriptor.
+  uint32 frequency_;
+  ChannelLayout channel_layout_;
+};
+
+}  // namespace mp4
+
+}  // namespace media
+
+#endif  // MEDIA_MP4_AAC_H_
diff --git a/media/mp4/aac_unittest.cc b/media/mp4/aac_unittest.cc
new file mode 100644
index 0000000..2f61de5
--- /dev/null
+++ b/media/mp4/aac_unittest.cc
@@ -0,0 +1,104 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/mp4/aac.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace media {
+
+namespace mp4 {
+
+TEST(AACTest, BasicProfileTest) {
+  AAC aac;
+  uint8 buffer[] = {0x12, 0x10};
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_TRUE(aac.Parse(data));
+  EXPECT_EQ(aac.frequency(), 44100u);
+  EXPECT_EQ(aac.channel_layout(), CHANNEL_LAYOUT_STEREO);
+}
+
+TEST(AACTest, ExtensionTest) {
+  AAC aac;
+  uint8 buffer[] = {0x13, 0x08, 0x56, 0xe5, 0x9d, 0x48, 0x80};
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_TRUE(aac.Parse(data));
+  EXPECT_EQ(aac.frequency(), 48000u);
+  EXPECT_EQ(aac.channel_layout(), CHANNEL_LAYOUT_STEREO);
+}
+
+TEST(AACTest, SixChannelTest) {
+  AAC aac;
+  uint8 buffer[] = {0x11, 0xb0};
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_TRUE(aac.Parse(data));
+  EXPECT_EQ(aac.frequency(), 48000u);
+  EXPECT_EQ(aac.channel_layout(), CHANNEL_LAYOUT_5_1);
+}
+
+TEST(AACTest, DataTooShortTest) {
+  AAC aac;
+  std::vector<uint8> data;
+
+  EXPECT_FALSE(aac.Parse(data));
+
+  data.push_back(0x12);
+  EXPECT_FALSE(aac.Parse(data));
+}
+
+TEST(AACTest, IncorrectProfileTest) {
+  AAC aac;
+  uint8 buffer[] = {0x0, 0x08};
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_FALSE(aac.Parse(data));
+
+  data[0] = 0x08;
+  EXPECT_TRUE(aac.Parse(data));
+
+  data[0] = 0x28;
+  EXPECT_FALSE(aac.Parse(data));
+}
+
+TEST(AACTest, IncorrectFrequencyTest) {
+  AAC aac;
+  uint8 buffer[] = {0x0f, 0x88};
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_FALSE(aac.Parse(data));
+
+  data[0] = 0x0e;
+  data[1] = 0x08;
+  EXPECT_TRUE(aac.Parse(data));
+}
+
+TEST(AACTest, IncorrectChannelTest) {
+  AAC aac;
+  uint8 buffer[] = {0x0e, 0x00};
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_FALSE(aac.Parse(data));
+
+  data[1] = 0x08;
+  EXPECT_TRUE(aac.Parse(data));
+}
+
+}  // namespace mp4
+
+}  // namespace media
diff --git a/media/mp4/avc.cc b/media/mp4/avc.cc
index faf9939..2999466 100644
--- a/media/mp4/avc.cc
+++ b/media/mp4/avc.cc
@@ -88,27 +88,5 @@ bool AVC::InsertParameterSets(const AVCDecoderConfigurationRecord& avc_config,
   return true;
 }
 
-// static
-ChannelLayout AVC::ConvertAACChannelCountToChannelLayout(int count) {
-  switch (count) {
-    case 1:
-      return CHANNEL_LAYOUT_MONO;
-    case 2:
-      return CHANNEL_LAYOUT_STEREO;
-    case 3:
-      return CHANNEL_LAYOUT_SURROUND;
-    case 4:
-      return CHANNEL_LAYOUT_4_0;
-    case 5:
-      return CHANNEL_LAYOUT_5_0;
-    case 6:
-      return CHANNEL_LAYOUT_5_1;
-    case 8:
-      return CHANNEL_LAYOUT_7_1;
-    default:
-      return CHANNEL_LAYOUT_UNSUPPORTED;
-  }
-}
-
 }  // namespace mp4
 }  // namespace media
diff --git a/media/mp4/avc.h b/media/mp4/avc.h
index 2767c14..8e826b0 100644
--- a/media/mp4/avc.h
+++ b/media/mp4/avc.h
@@ -8,7 +8,6 @@
 #include <vector>
 
 #include "base/basictypes.h"
-#include "media/base/channel_layout.h"
 #include "media/base/media_export.h"
 
 namespace media {
@@ -23,11 +22,8 @@ class MEDIA_EXPORT AVC {
   static bool InsertParameterSets(
       const AVCDecoderConfigurationRecord& avc_config,
       std::vector<uint8>* buffer);
-
-  static ChannelLayout ConvertAACChannelCountToChannelLayout(int count);
 };
 
-
 }  // namespace mp4
 }  // namespace media
 
diff --git a/media/mp4/box_definitions.cc b/media/mp4/box_definitions.cc
index ff86372..eb43530 100644
--- a/media/mp4/box_definitions.cc
+++ b/media/mp4/box_definitions.cc
@@ -5,8 +5,7 @@
 #include "media/mp4/box_definitions.h"
 
 #include "base/logging.h"
-#include "media/mp4/box_reader.h"
-#include "media/mp4/fourccs.h"
+#include "media/mp4/es_descriptor.h"
 #include "media/mp4/rcheck.h"
 
 namespace media {
@@ -389,6 +388,29 @@ bool VideoSampleEntry::Parse(BoxReader* reader) {
   return true;
 }
 
+ElementaryStreamDescriptor::ElementaryStreamDescriptor() {}
+
+ElementaryStreamDescriptor::~ElementaryStreamDescriptor() {}
+
+FourCC ElementaryStreamDescriptor::BoxType() const {
+  return FOURCC_ESDS;
+}
+
+bool ElementaryStreamDescriptor::Parse(BoxReader* reader) {
+  std::vector<uint8> data;
+  ESDescriptor es_desc;
+
+  RCHECK(reader->ReadFullBoxHeader());
+  RCHECK(reader->ReadVec(&data, reader->size() - reader->pos()));
+  RCHECK(es_desc.Parse(data));
+
+  object_type = es_desc.object_type();
+
+  RCHECK(aac.Parse(es_desc.decoder_specific_info()));
+
+  return true;
+}
+
 AudioSampleEntry::AudioSampleEntry()
     : format(FOURCC_NULL),
       data_reference_index(0),
@@ -397,6 +419,7 @@ AudioSampleEntry::AudioSampleEntry()
       samplerate(0) {}
 
 AudioSampleEntry::~AudioSampleEntry() {}
+
 FourCC AudioSampleEntry::BoxType() const {
   DCHECK(false) << "AudioSampleEntry should be parsed according to the "
                 << "handler type recovered in its Media ancestor.";
@@ -419,6 +442,7 @@ bool AudioSampleEntry::Parse(BoxReader* reader) {
   if (format == FOURCC_ENCA) {
     RCHECK(reader->ReadChild(&sinf));
   }
+  RCHECK(reader->ReadChild(&esds));
   return true;
 }
 
diff --git a/media/mp4/box_definitions.h b/media/mp4/box_definitions.h
index 52a0e86..0b7e771 100644
--- a/media/mp4/box_definitions.h
+++ b/media/mp4/box_definitions.h
@@ -11,6 +11,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "media/base/media_export.h"
+#include "media/mp4/aac.h"
 #include "media/mp4/avc.h"
 #include "media/mp4/box_reader.h"
 #include "media/mp4/fourccs.h"
@@ -184,6 +185,13 @@ struct VideoSampleEntry : Box {
   AVCDecoderConfigurationRecord avcc;
 };
 
+struct ElementaryStreamDescriptor : Box {
+  DECLARE_BOX_METHODS(ElementaryStreamDescriptor);
+
+  uint8 object_type;
+  AAC aac;
+};
+
 struct AudioSampleEntry : Box {
   DECLARE_BOX_METHODS(AudioSampleEntry);
 
@@ -194,6 +202,7 @@ struct AudioSampleEntry : Box {
   uint32 samplerate;
 
   ProtectionSchemeInfo sinf;
+  ElementaryStreamDescriptor esds;
 };
 
 struct SampleDescription : Box {
diff --git a/media/mp4/es_descriptor.cc b/media/mp4/es_descriptor.cc
new file mode 100644
index 0000000..1cb4c65
--- /dev/null
+++ b/media/mp4/es_descriptor.cc
@@ -0,0 +1,112 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/mp4/es_descriptor.h"
+
+#include "media/base/bit_reader.h"
+#include "media/mp4/rcheck.h"
+
+// The elementary stream size is specific by up to 4 bytes.
+// The MSB of a byte indicates if there are more bytes for the size.
+static bool ReadESSize(media::BitReader* reader, uint32* size) {
+  uint8 msb;
+  uint8 byte;
+
+  *size = 0;
+
+  for (size_t i = 0; i < 4; ++i) {
+    RCHECK(reader->ReadBits(1, &msb));
+    RCHECK(reader->ReadBits(7, &byte));
+    *size = (*size << 7) + byte;
+
+    if (msb == 0)
+      break;
+  }
+
+  return true;
+}
+
+namespace media {
+
+namespace mp4 {
+
+ESDescriptor::ESDescriptor()
+    : object_type_(kForbidden) {
+}
+
+ESDescriptor::~ESDescriptor() {}
+
+bool ESDescriptor::Parse(const std::vector<uint8>& data) {
+  BitReader reader(&data[0], data.size());
+  uint8 tag;
+  uint32 size;
+  uint8 stream_dependency_flag;
+  uint8 url_flag;
+  uint8 ocr_stream_flag;
+
+  RCHECK(reader.ReadBits(8, &tag));
+  RCHECK(tag == kESDescrTag);
+  RCHECK(ReadESSize(&reader, &size));
+  RCHECK(static_cast<off_t>(size * CHAR_BIT) <= reader.NumBitsLeft());
+
+  RCHECK(reader.SkipBits(16));  // ES_ID
+  RCHECK(reader.ReadBits(1, &stream_dependency_flag));
+  RCHECK(reader.ReadBits(1, &url_flag));
+  RCHECK(reader.ReadBits(1, &ocr_stream_flag));
+  RCHECK(reader.SkipBits(5));  // streamPriority
+
+  if (stream_dependency_flag)
+    reader.SkipBits(16);  // dependsOn_ES_ID;
+  RCHECK(!url_flag);  // We don't support url flag
+  if (ocr_stream_flag)
+    reader.SkipBits(16);  // OCR_ES_Id
+
+  RCHECK(ParseDecoderConfigDescriptor(&reader));
+
+  return true;
+}
+
+uint8 ESDescriptor::object_type() const {
+  return object_type_;
+}
+
+const std::vector<uint8>& ESDescriptor::decoder_specific_info() const {
+  return decoder_specific_info_;
+}
+
+bool ESDescriptor::ParseDecoderConfigDescriptor(BitReader* reader) {
+  uint8 tag;
+  uint32 size;
+
+  RCHECK(reader->ReadBits(8, &tag));
+  RCHECK(tag == kDecoderConfigDescrTag);
+  RCHECK(ReadESSize(reader, &size));
+  RCHECK(static_cast<off_t>(size * CHAR_BIT) <= reader->NumBitsLeft());
+
+  RCHECK(reader->ReadBits(8, &object_type_));
+  RCHECK(reader->SkipBits(96));
+  RCHECK(ParseDecoderSpecificInfo(reader));
+
+  return true;
+}
+
+bool ESDescriptor::ParseDecoderSpecificInfo(BitReader* reader) {
+  uint8 tag;
+  uint32 size;
+
+  RCHECK(reader->ReadBits(8, &tag));
+  RCHECK(tag == kDecoderSpecificInfoTag);
+  RCHECK(ReadESSize(reader, &size));
+  RCHECK(static_cast<off_t>(size * CHAR_BIT) <= reader->NumBitsLeft());
+
+  decoder_specific_info_.resize(size);
+  for (uint32 i = 0; i < size; ++i)
+    RCHECK(reader->ReadBits(8, &decoder_specific_info_[i]));
+
+  return true;
+}
+
+}  // namespace mp4
+
+}  // namespace media
diff --git a/media/mp4/es_descriptor.h b/media/mp4/es_descriptor.h
new file mode 100644
index 0000000..daddbc0
--- /dev/null
+++ b/media/mp4/es_descriptor.h
@@ -0,0 +1,57 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_MP4_ES_DESCRIPTOR_H_
+#define MEDIA_MP4_ES_DESCRIPTOR_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class BitReader;
+
+namespace mp4 {
+
+// The following values are extracted from ISO 14496 Part 1 Table 5 -
+// objectTypeIndication Values. Only values currently in use are included.
+enum ObjectType {
+  kForbidden = 0,
+  kISO_14496_3 = 0x40  // MPEG4 AAC
+};
+
+// This class parse object type and decoder specific information from an
+// elementary stream descriptor, which is usually contained in an esds box.
+// Please refer to ISO 14496 Part 1 7.2.6.5 for more details.
+class MEDIA_EXPORT ESDescriptor {
+ public:
+  ESDescriptor();
+  ~ESDescriptor();
+
+  bool Parse(const std::vector<uint8>& data);
+
+  uint8 object_type() const;
+  const std::vector<uint8>& decoder_specific_info() const;
+
+ private:
+  enum Tag {
+    kESDescrTag = 0x03,
+    kDecoderConfigDescrTag = 0x04,
+    kDecoderSpecificInfoTag = 0x05
+  };
+
+  bool ParseDecoderConfigDescriptor(BitReader* reader);
+  bool ParseDecoderSpecificInfo(BitReader* reader);
+
+  uint8 object_type_;
+  std::vector<uint8> decoder_specific_info_;
+};
+
+}  // namespace mp4
+
+}  // namespace media
+
+#endif  // MEDIA_MP4_ES_DESCRIPTOR_H_
diff --git a/media/mp4/es_descriptor_unittest.cc b/media/mp4/es_descriptor_unittest.cc
new file mode 100644
index 0000000..c3a39fb
--- /dev/null
+++ b/media/mp4/es_descriptor_unittest.cc
@@ -0,0 +1,92 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/mp4/es_descriptor.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace media {
+
+namespace mp4 {
+
+TEST(ESDescriptorTest, SingleByteLengthTest) {
+  ESDescriptor es_desc;
+  uint8 buffer[] = {
+    0x03, 0x19, 0x00, 0x01, 0x00, 0x04, 0x11, 0x40,
+    0x15, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x05, 0x02, 0x12, 0x10,
+    0x06, 0x01, 0x02
+  };
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_EQ(es_desc.object_type(), kForbidden);
+  EXPECT_TRUE(es_desc.Parse(data));
+  EXPECT_EQ(es_desc.object_type(), kISO_14496_3);
+  EXPECT_EQ(es_desc.decoder_specific_info().size(), 2u);
+  EXPECT_EQ(es_desc.decoder_specific_info()[0], 0x12);
+  EXPECT_EQ(es_desc.decoder_specific_info()[1], 0x10);
+}
+
+TEST(ESDescriptorTest, NonAACTest) {
+  ESDescriptor es_desc;
+  uint8 buffer[] = {
+    0x03, 0x19, 0x00, 0x01, 0x00, 0x04, 0x11, 0x66,
+    0x15, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x05, 0x02, 0x12, 0x10,
+    0x06, 0x01, 0x02
+  };
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_TRUE(es_desc.Parse(data));
+  EXPECT_NE(es_desc.object_type(), kISO_14496_3);
+  EXPECT_EQ(es_desc.decoder_specific_info().size(), 2u);
+  EXPECT_EQ(es_desc.decoder_specific_info()[0], 0x12);
+  EXPECT_EQ(es_desc.decoder_specific_info()[1], 0x10);
+}
+
+TEST(ESDescriptorTest, MultiByteLengthTest) {
+  ESDescriptor es_desc;
+  uint8 buffer[] = {
+    0x03, 0x80, 0x19, 0x00, 0x01, 0x00, 0x04, 0x80,
+    0x80, 0x11, 0x40, 0x15, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+    0x80, 0x80, 0x80, 0x02, 0x12, 0x10, 0x06, 0x01,
+    0x02
+  };
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_TRUE(es_desc.Parse(data));
+  EXPECT_EQ(es_desc.object_type(), kISO_14496_3);
+  EXPECT_EQ(es_desc.decoder_specific_info().size(), 2u);
+  EXPECT_EQ(es_desc.decoder_specific_info()[0], 0x12);
+  EXPECT_EQ(es_desc.decoder_specific_info()[1], 0x10);
+}
+
+TEST(ESDescriptorTest, FiveByteLengthTest) {
+  ESDescriptor es_desc;
+  uint8 buffer[] = {
+    0x03, 0x80, 0x19, 0x00, 0x01, 0x00, 0x04, 0x80,
+    0x80, 0x11, 0x40, 0x15, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+    0x80, 0x80, 0x80, 0x80, 0x02, 0x12, 0x10, 0x06,
+    0x01, 0x02
+  };
+  std::vector<uint8> data;
+
+  data.assign(buffer, buffer + sizeof(buffer));
+
+  EXPECT_TRUE(es_desc.Parse(data));
+  EXPECT_EQ(es_desc.object_type(), kISO_14496_3);
+  EXPECT_EQ(es_desc.decoder_specific_info().size(), 0u);
+}
+
+}  // namespace mp4
+
+}  // namespace media
diff --git a/media/mp4/mp4_stream_parser.cc b/media/mp4/mp4_stream_parser.cc
index bb2a95c..ebaa2a2 100644
--- a/media/mp4/mp4_stream_parser.cc
+++ b/media/mp4/mp4_stream_parser.cc
@@ -13,6 +13,7 @@
 #include "media/base/video_decoder_config.h"
 #include "media/mp4/box_definitions.h"
 #include "media/mp4/box_reader.h"
+#include "media/mp4/es_descriptor.h"
 #include "media/mp4/rcheck.h"
 
 namespace media {
@@ -162,10 +163,13 @@ bool MP4StreamParser::ParseMoov(BoxReader* reader) {
       //         (entry.format == FOURCC_ENCA &&
       //          entry.sinf.format.format == FOURCC_MP4A));
 
-      const ChannelLayout layout =
-          AVC::ConvertAACChannelCountToChannelLayout(entry.channelcount);
-      audio_config.Initialize(kCodecAAC, entry.samplesize, layout,
-                              entry.samplerate, NULL, 0, false);
+      // Check if it is MPEG4 AAC defined in ISO 14496 Part 3.
+      RCHECK(entry.esds.object_type == kISO_14496_3);
+      aac_ = entry.esds.aac;
+      audio_config.Initialize(kCodecAAC, entry.samplesize,
+                              aac_.channel_layout(), aac_.frequency(),
+                              NULL, 0, false);
+
       has_audio_ = true;
       audio_track_id_ = track->header.track_id;
     }
@@ -291,6 +295,10 @@ bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
     }
   }
 
+  if (audio) {
+    aac_.ConvertEsdsToADTS(&frame_buf);
+  }
+
   scoped_refptr<StreamParserBuffer> stream_buf =
     StreamParserBuffer::CopyFrom(&frame_buf[0], frame_buf.size(),
                                  runs_.is_keyframe());
diff --git a/media/mp4/mp4_stream_parser.h b/media/mp4/mp4_stream_parser.h
index 7d9be27..706aa65 100644
--- a/media/mp4/mp4_stream_parser.h
+++ b/media/mp4/mp4_stream_parser.h
@@ -11,6 +11,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "media/base/media_export.h"
 #include "media/base/stream_parser.h"
+#include "media/mp4/aac.h"
 #include "media/mp4/offset_byte_queue.h"
 #include "media/mp4/track_run_iterator.h"
 
@@ -85,8 +86,9 @@ class MEDIA_EXPORT MP4StreamParser : public StreamParser {
   uint32 audio_track_id_;
   uint32 video_track_id_;
 
-  // We keep this around to avoid having to go digging through the moov with
+  // We keep them around to avoid having to go digging through the moov with
   // every frame.
+  AAC aac_;
   uint8 size_of_nalu_length_;
 
   DISALLOW_COPY_AND_ASSIGN(MP4StreamParser);