Add VAVDA, the VAAPI Video Decode Accelerator for Intel CPUs.

content/common/gpu/media/h264_parser.cc

+// 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.
+

[Ami GONE FROM CHROMIUM, 2012/03/21 13:16:24]

Not part of this CL?

+#include "h264_parser.h"
+
+#include "base/logging.h"
+#include "base/stl_util.h"
+
+#include <fstream>
+H264BitReader::H264BitReader()
+  : data_(NULL),
+    bytes_left_(0),
+    curr_byte_(0),
+    bits_in_curr_byte_(0)
+{}
+
+H264BitReader::~H264BitReader() {}
+
+bool H264BitReader::Initialize(uint8* data, size_t size) {
+  DCHECK(data);
+
+  if (size < 1)
+    return false;
+
+  data_ = data;
+  bytes_left_ = size;
+  bits_in_curr_byte_ = 0;
+  // for detecting emulation-prevention three-byte sequences
+  prev_two_bytes_ = 0xffff;
+
+  return true;
+}
+
+bool 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) {
+    // skip
+    ++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_++;
+  --bytes_left_;
+  bits_in_curr_byte_ = 8;
+
+  prev_two_bytes_ = (prev_two_bytes_ << 8) | curr_byte_;
+
+  return true;
+}
+
+bool H264BitReader::ReadBits(int num_bits, uint32 *out) {
+  int bits_left = num_bits;
+  *out = 0;
+  DCHECK(num_bits <= 32);
+
+  while (bits_in_curr_byte_ < bits_left) {
+    // Take all that's left in current byte
+    // shift to make space for the rest
+    *out = (curr_byte_ << (num_bits - bits_in_curr_byte_));
+    bits_left -= bits_in_curr_byte_;
+
+    if (!UpdateCurrByte())
+      return false;
+  }
+
+  *out |= (curr_byte_ >> (bits_in_curr_byte_ - bits_left));
+  *out &= ((1 << num_bits) - 1);
+  bits_in_curr_byte_ -= bits_left;
+
+  return true;
+}
+
+bool H264BitReader::MoreRBSPData() {
+  // make sure we have more bits if we are at 0 bits in current byte
+  // if updating current byte fails, we don't have more data anyway
+  if (bits_in_curr_byte_ == 0)
+    if (!UpdateCurrByte())
+      return false;
+
+  // not on last byte?
+  if (bytes_left_ > 0)
+    return true;
+
+  // last byte, look for stop bit; if there is one, and there are still
+  // preceding bits in front of it the byte before it, we have more data
+  // if the last bit == 1 we find is our current bit, no more data
+  for (int i = 0; i < bits_in_curr_byte_ - 1; ++i) {
+    if ((curr_byte_ >> i) & 0x01)
+      return true;
+  }
+
+  return false;
+}
+
+#define read_bits_or_return(num_bits, out)                  \
+do {                                                        \
+  uint32 out32;                                             \
+  if (!br_.ReadBits(num_bits, &out32)) {                    \
+    LOG(INFO) << "Error in stream: unexpected end of data"; \
+    DLOG(INFO) << "While trying to read " #out;             \
+    return kInvalidStream;                                  \
+  }                                                         \
+  *out = out32;                                             \
+} while(0)
+
+#define read_ue_or_return(out)                      \
+do {                                                \
+  uint32 out32;                                     \
+  if (ReadUE(&out32) != kOk) {                      \
+    LOG(INFO) << "Error in stream: invalid stream"; \
+    DLOG(INFO) << "While trying to read " #out;     \
+    return kInvalidStream;                          \
+  }                                                 \
+  *out = out32;                                     \
+} while(0)
+
+#define read_se_or_return(out)                      \
+do {                                                \
+  int32 out32;                                      \
+  if (ReadSE(&out32) != kOk) {                      \
+    LOG(INFO) << "Error in stream: invalid stream"; \
+    DLOG(INFO) << "While trying to read " #out;     \
+    return kInvalidStream;                          \
+  }                                                 \
+  *out = out32;                                     \
+} while(0)
+
+#define range_in_or_return(val, low, high)             \
+do {                                                   \
+  if ((val) < (low) || (val) > (high)) {               \
+    LOG(INFO) << "Error in stream: invalid value";     \
+    DLOG(INFO) << "Expected " #val " to be in range "  \
+               << "[" << (low) << ":" << (high) << "]" \
+               << "found " << (val) << " instead";     \
+    return kInvalidStream;                             \
+  }                                                    \
+} while(0)
+
+#define true_or_return(a)                          \
+do {                                               \
+  if (!(a)) {                                      \
+    LOG(INFO) << "Error in stream: invalid value"; \
+    DLOG(INFO) << "Expected " << #a;               \
+    return kInvalidStream;                         \
+  }                                                \
+} while(0)
+
+
+H264Parser::H264Parser() {
+  Reset();
+}
+
+H264Parser::~H264Parser() {
+  STLDeleteContainerPairSecondPointers(active_SPSes_.begin(),
+                                       active_SPSes_.end());
+  STLDeleteContainerPairSecondPointers(active_PPSes_.begin(),
+                                       active_PPSes_.end());
+}
+
+void H264Parser::Reset() {
+  /*STLDeleteContainerPairSecondPointers(active_SPSes_.begin(),
+                                       active_SPSes_.end());
+  active_SPSes_.clear();
+
+  STLDeleteContainerPairSecondPointers(active_PPSes_.begin(),
+                                       active_PPSes_.end());
+  active_PPSes_.clear();*/
+  bytes_left_ = 0;
+  stream_ = NULL;
+}
+
+void H264Parser::SetStream(uint8* stream, size_t stream_size) {
+  DCHECK(stream);
+  DCHECK(stream_size > 0);
+
+  stream_ = stream;
+  bytes_left_ = stream_size;
+}
+
+H264PPS* H264Parser::GetPPS(uint8 pps_id) {
+  PPSById::iterator it = active_PPSes_.find(pps_id);
+  if (it == active_PPSes_.end())
+    return NULL;
+
+  return it->second;
+}
+
+H264SPS* H264Parser::GetSPS(uint8 sps_id) {
+  SPSById::iterator it = active_SPSes_.find(sps_id);
+  if (it == active_SPSes_.end())
+    return NULL;
+
+  return it->second;
+}
+
+static inline bool IsStartCode(uint8* data) {
+  DCHECK(data);
+  return data[0] == 0x00 && data[1] == 0x00 && data[2] == 0x01;
+}
+
+// Find offset from start of data to next NALU start code
+// and size of found start code (3 or 4 bytes)
+static bool FindStartCode(uint8* data, size_t data_size,
+                          size_t* offset,
+                          size_t *start_code_size) {
+  int bytes_left = data_size;
+
+  while (bytes_left > 3) {
+
+    if (IsStartCode(data)) {
+      // found three-byte start code, set pointers at its beginning
+      *offset = data_size - bytes_left;
+      *start_code_size = 3;
+
+      // if there is a zero byte before this start code,
+      // then it's actually a four-byte start code, so backtrack one byte
+      if (*offset > 0 && *(data - 1) == 0x00) {
+        --(*offset);
+        ++(*start_code_size);
+      }
+
+      return true;
+    }
+
+    ++data;
+    --bytes_left;
+  }
+
+  // end of data
+  return false;
+}
+
+// Find the next NALU in stream, returning its start offset without the start
+// code (i.e. at the beginning of NALU data).
+// Size will include trailing zero bits, and will be from start offset to
+// before the start code of the next NALU (or end of stream).
+static bool LocateNalu(uint8* stream, size_t stream_size,
+                       size_t* nalu_start_off, size_t* nalu_size) {
+  size_t start_code_size;
+  *nalu_start_off = 0;
+
+  // find start code of the next NALU
+  if (!FindStartCode(stream, stream_size, nalu_start_off, &start_code_size)) {
+    DVLOG(4) << "Could not find start code, end of stream?";
+    return false;
+  }
+
+  // discard its start code
+  *nalu_start_off += start_code_size;
+  // move the stream to the beginning of it (skip the start code)
+  stream_size -= *nalu_start_off;
+  stream += *nalu_start_off;
+
+  // Find the start code of next NALU; if successful, NALU size is the number
+  // of bytes from after previous start code to before this one;
+  // if next start code is not found, it is still a valid NALU if there
+  // are still some bytes left after the first start code.
+  // nalu_size is the offset to the next start code
+  if (!FindStartCode(stream, stream_size, nalu_size, &start_code_size)) {
+    // end of stream (no next NALU), but still valid NALU if any bytes left
+    *nalu_size = stream_size;
+    if (*nalu_size < 1) {
+      DVLOG(3) << "End of stream";
+      return false;
+    }
+  }
+
+  return true;
+}
+
+H264Parser::Result H264Parser::ReadUE(uint32* val) {
+  int num_bits = -1;
+  uint8 bit;
+  uint32 rest;
+
+  // Count the number of contiguous zero bits
+  do {
+    read_bits_or_return(1, &bit);
+    num_bits++;
+  } while (bit == 0);
+
+  if (num_bits > 32)
+    return kInvalidStream;
+
+  // calculate exp-Golomb code value
+  *val = (1 << num_bits) - 1;
+
+  if (num_bits > 0) {
+    read_bits_or_return(num_bits, &rest);
+    *val += rest;
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ReadSE(int32* val) {
+  uint32 ue;
+  Result res;
+
+  // see Chapter 9 in the spec
+  res = ReadUE(&ue);
+  if (res != kOk)
+    return res;
+
+  if (ue % 2 == 0)
+    *val = -(ue / 2);
+  else
+    *val = ue / 2 + 1;
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseNextNalu(H264NALU *nalu) {
+  uint8 data;
+  size_t off_to_nalu_start;
+
+  DCHECK(stream_);
+
+  if (!LocateNalu(stream_, bytes_left_, &off_to_nalu_start, &nalu->size)) {
+    DVLOG(4) << "Could not find next NALU, bytes left in stream: "
+             << bytes_left_;
+    return kEOStream;
+  }
+
+  nalu->data = stream_ + off_to_nalu_start;
+  // initialize bit reader at the start of found NALU
+  br_.Initialize(nalu->data, nalu->size);
+  DVLOG(4) << "Looking for NALU, Stream bytes left: " << bytes_left_
+           << " off to next nalu: " << off_to_nalu_start;
+
+  // move parser state to after this NALU, so next time ParseNextNalu
+  // is called we will effectively be skipping it
+  // other parsing functions will use the bit reader for parsing
+  stream_ += off_to_nalu_start + nalu->size;
+  bytes_left_ -= off_to_nalu_start + nalu->size;
+
+  // read NALU header
+  // skip the forbidden_zero_bit, but check for it
+  read_bits_or_return(1, &data);
+  true_or_return(data == 0);
+
+  read_bits_or_return(2, &nalu->nal_ref_idc);
+  read_bits_or_return(5, &nalu->nal_unit_type);
+  true_or_return(nalu->nal_unit_type < 31);
+
+  DVLOG(4) << "Nalu type: " << (int)nalu->nal_unit_type
+           << " at: " << (void*)nalu->data << " size: " << nalu->size
+           << " ref: " << (int)nalu->nal_ref_idc;
+
+  return kOk;
+}
+
+// Default scaling lists (as per spec)
+static const uint8 default_4x4_intra[16] = {
+  6, 13, 13, 20, 20, 20, 28, 28, 28, 28, 32, 32, 32, 37, 37, 42, };
+
+static const uint8 default_4x4_inter[16] = {
+  10, 14, 14, 20, 20, 20, 24, 24, 24, 24, 27, 27, 27, 30, 30, 34, };
+
+static const uint8 default_8x8_intra[64] = {
+  6, 10, 10, 13, 11, 13, 16, 16, 16, 16, 18, 18, 18, 18, 18, 23,
+  23, 23, 23, 23, 23, 25, 25, 25, 25, 25, 25, 25, 27, 27, 27, 27,
+  27, 27, 27, 27, 29, 29, 29, 29, 29, 29, 29, 31, 31, 31, 31, 31,
+  31, 33, 33, 33, 33, 33, 36, 36, 36, 36, 38, 38, 38, 40, 40, 42, };
+
+static const uint8 default_8x8_inter[64] = {
+  9, 13, 13, 15, 13, 15, 17, 17, 17, 17, 19, 19, 19, 19, 19, 21,
+  21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 24, 24, 24, 24,
+  24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 27, 27, 27, 27, 27,
+  27, 28, 28, 28, 28, 28, 30, 30, 30, 30, 32, 32, 32, 33, 33, 35, };
+
+static inline void DefaultScalingList4x4(int i, uint8 scaling_list4x4[][16]) {
+  DCHECK(i < 6);
+
+  if (i < 3)
+    memcpy(scaling_list4x4[i], default_4x4_intra, sizeof(default_4x4_intra));
+  else if (i < 6)
+    memcpy(scaling_list4x4[i], default_4x4_inter, sizeof(default_4x4_inter));
+}
+
+static inline void DefaultScalingList8x8(int i, uint8 scaling_list8x8[][64]) {
+  DCHECK(i < 6);
+
+  if (i % 2 == 0)
+    memcpy(scaling_list8x8[i], default_8x8_intra, sizeof(default_8x8_intra));
+  else
+    memcpy(scaling_list8x8[i], default_8x8_inter, sizeof(default_8x8_inter));
+}
+
+static void FallbackScalingList4x4(int i,
+                                   const uint8 default_scaling_list_intra[],
+                                   const uint8 default_scaling_list_inter[],
+                                   uint8 scaling_list4x4[][16]) {
+  switch (i) {
+    case 0:
+      memcpy(scaling_list4x4[i], default_scaling_list_intra,
+          sizeof(default_scaling_list_intra));
+      break;
+
+    case 1:
+      memcpy(scaling_list4x4[i], scaling_list4x4[0],
+          sizeof(scaling_list4x4[0]));
+      break;
+
+    case 2:
+      memcpy(scaling_list4x4[i], scaling_list4x4[1],
+          sizeof(scaling_list4x4[1]));
+      break;
+
+    case 3:
+      memcpy(scaling_list4x4[i], default_scaling_list_inter,
+          sizeof(default_scaling_list_inter));
+      break;
+
+    case 4:
+      memcpy(scaling_list4x4[i], scaling_list4x4[3],
+          sizeof(scaling_list4x4[3]));
+      break;
+
+    case 5:
+      memcpy(scaling_list4x4[i], scaling_list4x4[4],
+          sizeof(scaling_list4x4[4]));
+      break;
+
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
+static void FallbackScalingList8x8(int i,
+                                   const uint8 default_scaling_list_intra[],
+                                   const uint8 default_scaling_list_inter[],
+                                   uint8 scaling_list8x8[][64]) {
+  switch (i) {
+    case 0:
+      memcpy(scaling_list8x8[i], default_scaling_list_intra,
+          sizeof(default_scaling_list_intra));
+      break;
+
+    case 1:
+      memcpy(scaling_list8x8[i], default_scaling_list_inter,
+          sizeof(default_scaling_list_inter));
+      break;
+
+    case 2:
+      memcpy(scaling_list8x8[i], scaling_list8x8[0],
+          sizeof(scaling_list8x8[0]));
+      break;
+
+    case 3:
+      memcpy(scaling_list8x8[i], scaling_list8x8[1],
+          sizeof(scaling_list8x8[1]));
+      break;
+
+    case 4:
+      memcpy(scaling_list8x8[i], scaling_list8x8[2],
+          sizeof(scaling_list8x8[2]));
+      break;
+
+    case 5:
+      memcpy(scaling_list8x8[i], scaling_list8x8[3],
+          sizeof(scaling_list8x8[3]));
+      break;
+
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
+H264Parser::Result H264Parser::ScalingList(uint8* scaling_list, int size,
+                                           bool* use_default) {
+  // see chapter 7.3.2.1.1.1
+  uint8 last_scale = 8;
+  uint8 next_scale = 8;
+  int32 delta_scale;
+
+  *use_default = false;
+
+  // TODO check if we need to scan in zigzag pattern for the driver
+  for (int j = 0; j < size; ++j) {
+    if (next_scale != 0) {
+      read_se_or_return(&delta_scale);
+      next_scale = (last_scale + delta_scale) & 0xff;
+
+      if (j == 0 && next_scale == 0) {
+        *use_default = true;
+        return kOk;
+      }
+    }
+
+    scaling_list[j] = (next_scale == 0) ? last_scale : next_scale;
+    last_scale = scaling_list[j];
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseSPSScalingLists(H264SPS* sps) {
+  // see 7.4.2.1.1
+  bool seq_scaling_list_present_flag;
+  bool use_default;
+  Result res;
+
+  // parse scaling_list4x4
+  for (int i = 0; i < 6; ++i) {
+    read_bits_or_return(1, &seq_scaling_list_present_flag);
+
+    if (seq_scaling_list_present_flag) {
+      res = ScalingList(sps->scaling_list4x4[i],
+                        sizeof(sps->scaling_list4x4[i]),
+                        &use_default);
+      if (res != kOk)
+        return res;
+
+      if (use_default)
+        DefaultScalingList4x4(i, sps->scaling_list4x4);
+
+    } else {
+        FallbackScalingList4x4(i, default_4x4_intra, default_4x4_inter,
+                               sps->scaling_list4x4);
+    }
+  }
+
+  // parse scaling_list8x8
+  for (int i = 0; i < (sps->chroma_format_idc != 3) ? 2 : 6; ++i) {
+    read_bits_or_return(1, &seq_scaling_list_present_flag);
+
+    if (seq_scaling_list_present_flag) {
+      res = ScalingList(sps->scaling_list8x8[i],
+                        sizeof(sps->scaling_list8x8[i]),
+                        &use_default);
+      if (res != kOk)
+        return res;
+
+      if (use_default)
+        DefaultScalingList8x8(i, sps->scaling_list8x8);
+
+    } else {
+        FallbackScalingList8x8(i, default_8x8_intra, default_8x8_inter,
+                              sps->scaling_list8x8);
+    }
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParsePPSScalingLists(H264SPS* sps,
+                                                    H264PPS* pps) {
+  // see 7.4.2.2
+  bool pic_scaling_list_present_flag;
+  bool use_default;
+  Result res;
+
+  for (int i = 0; i < 6; ++i) {
+    read_bits_or_return(1, &pic_scaling_list_present_flag);
+
+    if (pic_scaling_list_present_flag) {
+      res = ScalingList(pps->scaling_list4x4[i],
+                        sizeof(pps->scaling_list4x4[i]),
+                        &use_default);
+      if (res != kOk)
+        return res;
+
+      if (use_default) // check SPS scaling flag?
+        DefaultScalingList4x4(i, pps->scaling_list4x4);
+
+    } else {
+      if (sps->seq_scaling_matrix_present_flag) {
+        // table 7-2 fallback rule A
+        FallbackScalingList4x4(i, default_4x4_intra, default_4x4_inter,
+                               pps->scaling_list4x4);
+      } else {
+        // table 7-2 fallback rule B
+        FallbackScalingList4x4(i, sps->scaling_list4x4[0],
+                               sps->scaling_list4x4[3], pps->scaling_list4x4);
+      }
+    }
+  }
+
+  if (pps->transform_8x8_mode_flag) {
+    for (int i = 0; i < (sps->chroma_format_idc != 3) ? 2 : 6; ++i) {
+      read_bits_or_return(1, &pic_scaling_list_present_flag);
+
+      if (pic_scaling_list_present_flag) {
+        res = ScalingList(pps->scaling_list8x8[i],
+                          sizeof(pps->scaling_list8x8[i]),
+                          &use_default);
+        if (res != kOk)
+          return res;
+
+        if (use_default)
+          DefaultScalingList8x8(i, pps->scaling_list8x8);
+
+      } else {
+        if (sps->seq_scaling_matrix_present_flag) {
+          // table 7-2 fallback rule A
+          FallbackScalingList8x8(i, default_8x8_intra,
+                                 default_8x8_inter, pps->scaling_list8x8);
+        } else {
+          // table 7-2 fallback rule B
+          FallbackScalingList8x8(i, sps->scaling_list8x8[0],
+                                 sps->scaling_list8x8[1], pps->scaling_list8x8);
+        }
+      }
+    }
+  }
+  return kOk;
+}
+
+static void FillDefaultSeqScalingLists(H264SPS* sps) {
+  // assumes uint8s in arrays
+  memset(sps->scaling_list4x4, 16, sizeof(sps->scaling_list4x4));
+  memset(sps->scaling_list8x8, 16, sizeof(sps->scaling_list8x8));
+}
+
+H264Parser::Result H264Parser::ParseSPS(int* sps_id) {
+  // see 7.4.2.1
+  uint8 data;
+  Result res;
+
+  *sps_id = -1;
+
+  scoped_ptr<H264SPS> sps(new H264SPS);
+  CHECK(sps != NULL);
+  memset(sps.get(), 0, sizeof(H264SPS));
+
+  read_bits_or_return(8, &sps->profile_idc);
+  // skip constraint_setx_flag and reserved flags
+  read_bits_or_return(8, &data);
+  read_bits_or_return(8, &sps->level_idc);
+  read_ue_or_return(&sps->seq_parameter_set_id);
+  true_or_return(sps->seq_parameter_set_id < 32);
+
+  if (sps->profile_idc == 100 || sps->profile_idc == 110 ||
+      sps->profile_idc == 122 || sps->profile_idc == 244 ||
+      sps->profile_idc ==  44 || sps->profile_idc ==  83 ||
+      sps->profile_idc ==  86 || sps->profile_idc == 118 ||
+      sps->profile_idc == 128) {
+    read_ue_or_return(&sps->chroma_format_idc);
+    true_or_return(sps->chroma_format_idc < 4);
+
+    if (sps->chroma_format_idc == 3)
+      read_bits_or_return(1, &sps->separate_colour_plane_flag);
+
+    if (sps->separate_colour_plane_flag)
+      sps->chroma_array_type = 0;
+    else
+      sps->chroma_array_type = sps->chroma_format_idc;
+
+    read_ue_or_return(&sps->bit_depth_luma_minus8);
+    true_or_return(sps->bit_depth_luma_minus8 < 7);
+
+    read_ue_or_return(&sps->bit_depth_chroma_minus8);
+    true_or_return(sps->bit_depth_chroma_minus8 < 7);
+
+    read_bits_or_return(1, &sps->qpprime_y_zero_transform_bypass_flag);
+    read_bits_or_return(1, &sps->seq_scaling_matrix_present_flag);
+
+    if (sps->seq_scaling_matrix_present_flag) {
+      DVLOG(4) << "Scaling matrix present";
+      res = ParseSPSScalingLists(sps.get());
+      if (res != kOk)
+        return res;
+    } else {
+      FillDefaultSeqScalingLists(sps.get());
+    }
+  }
+
+  read_ue_or_return(&sps->log2_max_frame_num_minus4);
+  true_or_return(sps->log2_max_frame_num_minus4 < 13);
+
+  read_ue_or_return(&sps->pic_order_cnt_type);
+  true_or_return(sps->pic_order_cnt_type < 3);
+
+  if (sps->pic_order_cnt_type == 0) {
+    read_ue_or_return(&sps->log2_max_pic_order_cnt_lsb_minus4);
+    true_or_return(sps->log2_max_pic_order_cnt_lsb_minus4 < 13);
+  } else if (sps->pic_order_cnt_type == 1) {
+    read_bits_or_return(1, &sps->delta_pic_order_always_zero_flag);
+    read_se_or_return(&sps->offset_for_non_ref_pic);
+    read_se_or_return(&sps->offset_for_top_to_bottom_field);
+    read_ue_or_return(&sps->num_ref_frames_in_pic_order_cnt_cycle);
+    for (int i = 0; i < sps->num_ref_frames_in_pic_order_cnt_cycle; ++i)
+      read_se_or_return(&sps->offset_for_ref_frame[i]);
+  }
+
+  read_ue_or_return(&sps->max_num_ref_frames);
+  read_bits_or_return(1, &sps->gaps_in_frame_num_value_allowed_flag);
+
+  if (sps->gaps_in_frame_num_value_allowed_flag)
+    return kUnsupportedStream;
+
+  read_ue_or_return(&sps->pic_width_in_mbs_minus1);
+  read_ue_or_return(&sps->pic_height_in_map_units_minus1);
+
+  read_bits_or_return(1, &sps->frame_mbs_only_flag);
+  if (!sps->frame_mbs_only_flag)
+    read_bits_or_return(1, &sps->mb_adaptive_frame_field_flag);
+
+  read_bits_or_return(1, &sps->direct_8x8_inference_flag);
+
+  read_bits_or_return(1, &sps->frame_cropping_flag);
+  if (sps->frame_cropping_flag) {
+    read_ue_or_return(&sps->frame_crop_left_offset);
+    read_ue_or_return(&sps->frame_crop_right_offset);
+    read_ue_or_return(&sps->frame_crop_top_offset);
+    read_ue_or_return(&sps->frame_crop_bottom_offset);
+  }
+
+  read_bits_or_return(1, &sps->vui_parameters_present_flag);
+  if (sps->vui_parameters_present_flag) {
+    DLOG(INFO) << "VUI parameters present in SPS, ignoring";
+  }
+
+  // If an SPS with the same id already exists, replace it
+  SPSById::iterator it = active_SPSes_.find(sps->seq_parameter_set_id);
+  if (it != active_SPSes_.end()) {
+    delete it->second;
+    active_SPSes_.erase(it);
+  }
+
+  *sps_id = sps->seq_parameter_set_id;
+  active_SPSes_[sps->seq_parameter_set_id] = sps.release();
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParsePPS(int* pps_id) {
+  // see 7.4.2.2
+  H264SPS* sps;
+  Result res;
+
+  *pps_id = -1;
+
+  scoped_ptr<H264PPS> pps(new H264PPS);
+  CHECK(pps != NULL);
+  memset(pps.get(), 0, sizeof(H264PPS));
+
+  read_ue_or_return(&pps->pic_parameter_set_id);
+  read_ue_or_return(&pps->seq_parameter_set_id);
+  true_or_return(pps->seq_parameter_set_id < 32);
+
+  sps = GetSPS(pps->seq_parameter_set_id);
+  true_or_return(sps != NULL);
+
+  read_bits_or_return(1, &pps->entropy_coding_mode_flag);
+  read_bits_or_return(1, &pps->bottom_field_pic_order_in_frame_present_flag);
+
+  read_ue_or_return(&pps->num_slice_groups_minus1);
+  if (pps->num_slice_groups_minus1 > 1) {
+    DLOG(INFO) << "Slice groups not supported";
+    return kUnsupportedStream;
+  }
+
+  read_ue_or_return(&pps->num_ref_idx_l0_default_active_minus1);
+  true_or_return(pps->num_ref_idx_l0_default_active_minus1 < 32);
+
+  read_ue_or_return(&pps->num_ref_idx_l1_default_active_minus1);
+  true_or_return(pps->num_ref_idx_l1_default_active_minus1 < 32);
+
+  read_bits_or_return(1, &pps->weighted_pred_flag);
+  read_bits_or_return(2, &pps->weighted_bipred_idc);
+  true_or_return(pps->weighted_bipred_idc < 3);
+
+  read_se_or_return(&pps->pic_init_qp_minus26);
+  range_in_or_return(pps->pic_init_qp_minus26, -26, 25);
+
+  read_se_or_return(&pps->pic_init_qs_minus26);
+  range_in_or_return(pps->pic_init_qs_minus26, -26, 25);
+
+  read_se_or_return(&pps->chroma_qp_index_offset);
+  range_in_or_return(pps->chroma_qp_index_offset, -12, 12);
+
+  read_bits_or_return(1, &pps->deblocking_filter_control_present_flag);
+  read_bits_or_return(1, &pps->constrained_intra_pred_flag);
+  read_bits_or_return(1, &pps->redundant_pic_cnt_present_flag);
+
+  if (br_.MoreRBSPData()) {
+    read_bits_or_return(1, &pps->transform_8x8_mode_flag);
+    read_bits_or_return(1, &pps->pic_scaling_matrix_present_flag);
+
+    if (pps->pic_scaling_matrix_present_flag) {
+      DVLOG(4) << "Picture scaling matrix present";
+      res = ParsePPSScalingLists(sps, pps.get());
+      if (res != kOk)
+        return res;
+    }
+
+    read_se_or_return(&pps->second_chroma_qp_index_offset);
+  }
+
+  PPSById::iterator it = active_PPSes_.find(pps->pic_parameter_set_id);
+  if (it != active_PPSes_.end()) {
+    delete it->second;
+    active_PPSes_.erase(it);
+  }
+
+  *pps_id = pps->pic_parameter_set_id;
+  // If a PPS with the same id already exists, replace it
+  active_PPSes_[pps->pic_parameter_set_id] = pps.release();
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseRefPicListModification(
+    uint8 num_ref_idx_active_minus1,
+    H264ModificationOfPicNum* ref_list_mods) {
+  H264ModificationOfPicNum *pic_num_mod;
+
+  if (num_ref_idx_active_minus1 >= 32)
+    return kInvalidStream;
+
+  //for (int i = 0; i < num_ref_idx_active_minus1 + 1; ++i) {
+  for (int i = 0; i < 32; ++i) {
+    pic_num_mod = &ref_list_mods[i];
+    read_ue_or_return(&pic_num_mod->modification_of_pic_nums_idc);
+    true_or_return(pic_num_mod->modification_of_pic_nums_idc < 4);
+
+    switch (pic_num_mod->modification_of_pic_nums_idc) {
+      case 0:
+      case 1:
+        read_ue_or_return(&pic_num_mod->abs_diff_pic_num_minus1);
+        break;
+
+      case 2:
+        read_ue_or_return(&pic_num_mod->long_term_pic_num);
+        break;
+
+      case 3:
+        // per spec, list cannot be empty
+        if (i == 0)
+          return kInvalidStream;
+        return kOk;
+
+      default:
+        return kInvalidStream;
+    }
+  }
+
+  // if we got here, we didn't get loop end marker prematurely,
+  // so make sure it is there
+  uint8 modification_of_pic_nums_idc;
+  read_ue_or_return(&modification_of_pic_nums_idc);
+  true_or_return(modification_of_pic_nums_idc == 3);
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::RefPicListModification(H264SliceHeader* shdr) {
+  Result res;
+
+  if (shdr->slice_type % 5 != 2 && shdr->slice_type % 5 != 4) {
+    read_bits_or_return(1, &shdr->ref_pic_list_modification_flag_l0);
+    if (shdr->ref_pic_list_modification_flag_l0) {
+      res = ParseRefPicListModification(shdr->num_ref_idx_l0_active_minus1,
+                                        shdr->ref_list_l0_modifications);
+      if (res != kOk)
+        return res;
+    }
+  }
+
+  if (shdr->slice_type % 5 == 1) {
+    read_bits_or_return(1, &shdr->ref_pic_list_modification_flag_l1);
+    if (shdr->ref_pic_list_modification_flag_l1) {
+      res = ParseRefPicListModification(shdr->num_ref_idx_l1_active_minus1,
+                                        shdr->ref_list_l1_modifications);
+      if (res != kOk)
+        return res;
+    }
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseWeightingFactors(
+    H264WeightingFactors* w_facts,
+    int num_ref_idx_active_minus1,
+    uint8 chroma_array_type,
+    uint8 luma_log2_weight_denom,
+    uint8 chroma_log2_weight_denom) {
+
+  int16 def_luma_weight = 1 << luma_log2_weight_denom;
+  int16 def_chroma_weight = 1 << chroma_log2_weight_denom;
+
+  for (int i = 0; i < num_ref_idx_active_minus1 + 1; ++i) {
+    read_bits_or_return(1, &w_facts->luma_weight_flag);
+    if (w_facts->luma_weight_flag) {
+      read_se_or_return(&w_facts->luma_weight[i]);
+      range_in_or_return(w_facts->luma_weight[i], -128, 127);
+
+      read_se_or_return(&w_facts->luma_offset[i]);
+      range_in_or_return(w_facts->luma_offset[i], -128, 127);
+    } else {
+      w_facts->luma_weight[i] = def_luma_weight;
+      w_facts->luma_offset[i] = 0;
+    }
+
+    if (chroma_array_type != 0) {
+      read_bits_or_return(1, &w_facts->chroma_weight_flag);
+      if (w_facts->chroma_weight_flag) {
+        for (int j = 0; j < 2; ++j) {
+          read_se_or_return(&w_facts->chroma_weight[i][j]);
+          range_in_or_return(w_facts->chroma_weight[i][j], -128, 127);
+
+          read_se_or_return(&w_facts->chroma_offset[i][j]);
+          range_in_or_return(w_facts->chroma_offset[i][j], -128, 127);
+        }
+      } else {
+        for (int j = 0; j < 2; ++j) {
+          w_facts->chroma_weight[i][j] = def_chroma_weight;
+          w_facts->chroma_offset[i][j] = 0;
+        }
+      }
+    }
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParsePredWeightTable(H264SliceHeader *shdr,
+                                                    H264SPS* sps) {
+  Result res;
+
+  read_ue_or_return(&shdr->luma_log2_weight_denom);
+  true_or_return(shdr->luma_log2_weight_denom < 8);
+
+  if (sps->chroma_array_type != 0)
+    read_ue_or_return(&shdr->chroma_log2_weight_denom);
+  true_or_return(shdr->chroma_log2_weight_denom < 8);
+
+  res = ParseWeightingFactors(&shdr->pred_weight_table_l0,
+                              shdr->num_ref_idx_l0_active_minus1,
+                              sps->chroma_array_type,
+                              shdr->luma_log2_weight_denom,
+                              shdr->chroma_log2_weight_denom);
+  if (res != kOk)
+    return res;
+
+  if (shdr->slice_type % 5 == 1) {
+    res = ParseWeightingFactors(&shdr->pred_weight_table_l1,
+                                shdr->num_ref_idx_l1_active_minus1,
+                                sps->chroma_array_type,
+                                shdr->luma_log2_weight_denom,
+                                shdr->chroma_log2_weight_denom);
+    if (res != kOk)
+      return res;
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseDecRefPicMarking(H264SliceHeader *shdr) {
+
+  if (shdr->idr_pic_flag) {
+    read_bits_or_return(1, &shdr->no_output_of_prior_pics_flag);
+    read_bits_or_return(1, &shdr->long_term_reference_flag);
+  } else {
+    read_bits_or_return(1, &shdr->adaptive_ref_pic_marking_mode_flag);
+
+    H264DecRefPicMarking* marking;
+    if (shdr->adaptive_ref_pic_marking_mode_flag) {
+      size_t i;
+      for (i = 0; i < arraysize(shdr->ref_pic_marking); ++i) {
+        marking = &shdr->ref_pic_marking[i];
+
+        read_ue_or_return(&marking->memory_mgmnt_control_operation);
+        if (marking->memory_mgmnt_control_operation == 0)
+          break;
+
+        if (marking->memory_mgmnt_control_operation == 1 ||
+            marking->memory_mgmnt_control_operation == 3)
+          read_ue_or_return(&marking->difference_of_pic_nums_minus1);
+
+        if (marking->memory_mgmnt_control_operation == 2)
+          read_ue_or_return(&marking->long_term_pic_num);
+
+        if (marking->memory_mgmnt_control_operation == 3 ||
+            marking->memory_mgmnt_control_operation == 6)
+          read_ue_or_return(&marking->long_term_frame_idx);
+
+        if (marking->memory_mgmnt_control_operation == 4)
+          read_ue_or_return(&marking->max_long_term_frame_idx_plus1);
+
+        if (marking->memory_mgmnt_control_operation > 6)
+          return kInvalidStream;
+      }
+
+      if (i == arraysize(shdr->ref_pic_marking)) {
+        LOG(INFO) << "Ran out of dec ref pic marking fields";
+        return kUnsupportedStream;
+      }
+    }
+  }
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseSliceHeader(H264SliceHeader* shdr,
+                                                H264NALU* nalu) {
+  // see 7.4.3
+  H264SPS* sps;
+  H264PPS* pps;
+  Result res;
+
+  memset(shdr, 0, sizeof(*shdr));
+
+  shdr->idr_pic_flag = ((nalu->nal_unit_type == 5) ? true : false);
+  shdr->nal_ref_idc = nalu->nal_ref_idc;
+  shdr->nalu_data = nalu->data;
+  shdr->nalu_size = nalu->size;
+
+  read_ue_or_return(&shdr->first_mb_in_slice);
+  read_ue_or_return(&shdr->slice_type);
+  true_or_return(shdr->slice_type < 10);
+
+  read_ue_or_return(&shdr->pic_parameter_set_id);
+
+  pps = GetPPS(shdr->pic_parameter_set_id);
+  true_or_return(pps != NULL);
+
+  sps = GetSPS(pps->seq_parameter_set_id);
+  true_or_return(sps != NULL);
+
+  if (sps->separate_colour_plane_flag) {
+    DLOG(INFO) << "Interlaced streams not supported";
+    return kUnsupportedStream;
+    //read_bits_or_return(2, &shdr->colour_plane_id);
+    //true_or_return(shdr->colour_plane_id < 3);
+  }
+
+  read_bits_or_return(sps->log2_max_frame_num_minus4 + 4,
+                      &shdr->frame_num);
+  if (!sps->frame_mbs_only_flag) {
+    read_bits_or_return(1, &shdr->field_pic_flag);
+    if (shdr->field_pic_flag) {
+      DLOG(INFO) << "Interlaced streams not supported";
+      return kUnsupportedStream;
+      //read_bits_or_return(1, &shdr->bottom_field_flag);
+    }
+  }
+
+  if (shdr->idr_pic_flag)
+    read_ue_or_return(&shdr->idr_pic_id);
+
+  if (sps->pic_order_cnt_type == 0) {
+    read_bits_or_return(sps->log2_max_pic_order_cnt_lsb_minus4 + 4,
+                        &shdr->pic_order_cnt_lsb);
+    if (pps->bottom_field_pic_order_in_frame_present_flag &&
+        !shdr->field_pic_flag)
+      read_se_or_return(&shdr->delta_pic_order_cnt_bottom);
+  }
+
+  if (sps->pic_order_cnt_type == 1 && !sps->delta_pic_order_always_zero_flag) {
+    read_se_or_return(&shdr->delta_pic_order_cnt[0]);
+    if (pps->bottom_field_pic_order_in_frame_present_flag &&
+        !shdr->field_pic_flag)
+      read_se_or_return(&shdr->delta_pic_order_cnt[1]);
+  }
+
+  if (pps->redundant_pic_cnt_present_flag) {
+    read_ue_or_return(&shdr->redundant_pic_cnt);
+    true_or_return(shdr->redundant_pic_cnt < 128);
+  }
+
+  if (IsH264BSlice(shdr))
+    read_bits_or_return(1, &shdr->direct_spatial_mv_pred_flag);
+
+  if (IsH264PSlice(shdr) || IsH264SPSlice(shdr) || IsH264BSlice(shdr)) {
+    read_bits_or_return(1, &shdr->num_ref_idx_active_override_flag);
+    if (shdr->num_ref_idx_active_override_flag) {
+      read_ue_or_return(&shdr->num_ref_idx_l0_active_minus1);
+      if (IsH264BSlice(shdr))
+        read_ue_or_return(&shdr->num_ref_idx_l1_active_minus1);
+    } else {
+      shdr->num_ref_idx_l0_active_minus1 =
+            pps->num_ref_idx_l0_default_active_minus1;
+      shdr->num_ref_idx_l1_active_minus1 =
+            pps->num_ref_idx_l1_default_active_minus1;
+    }
+  }
+  if (shdr->field_pic_flag) {
+    true_or_return(shdr->num_ref_idx_l0_active_minus1 < 32);
+    true_or_return(shdr->num_ref_idx_l1_active_minus1 < 32);
+  } else {
+    true_or_return(shdr->num_ref_idx_l0_active_minus1 < 16);
+    true_or_return(shdr->num_ref_idx_l1_active_minus1 < 16);
+  }
+
+  if (nalu->nal_unit_type == 20) {
+    return kUnsupportedStream;
+  } else {
+    res = RefPicListModification(shdr);
+    if (res != kOk)
+      return res;
+  }
+
+  if ((pps->weighted_pred_flag && (IsH264PSlice(shdr) || IsH264SPSlice(shdr)))
+      || (pps->weighted_bipred_idc == 1 && IsH264BSlice(shdr))) {
+    res = ParsePredWeightTable(shdr, sps);
+    if (res != kOk)
+      return res;
+  }
+
+  if (nalu->nal_ref_idc != 0) {
+    res = ParseDecRefPicMarking(shdr);
+    if (res != kOk)
+      return res;
+  }
+
+  if (pps->entropy_coding_mode_flag &&
+      !IsH264ISlice(shdr) && !IsH264SISlice(shdr)) {
+    read_ue_or_return(&shdr->cabac_init_idc);
+    true_or_return(shdr->cabac_init_idc < 3);
+  }
+
+  read_se_or_return(&shdr->slice_qp_delta);
+
+  if (IsH264SPSlice(shdr) || IsH264SISlice(shdr)) {
+    if (IsH264SPSlice(shdr))
+        read_bits_or_return(1, &shdr->sp_for_switch_flag);
+    read_se_or_return(&shdr->slice_qs_delta);
+  }
+
+  if (pps->deblocking_filter_control_present_flag) {
+    read_ue_or_return(&shdr->disable_deblocking_filter_idc);
+    true_or_return(shdr->disable_deblocking_filter_idc < 3);
+
+    if (shdr->disable_deblocking_filter_idc != 1) {
+      read_se_or_return(&shdr->slice_alpha_c0_offset_div2);
+      range_in_or_return(shdr->slice_alpha_c0_offset_div2, -6, 6);
+
+      read_se_or_return(&shdr->slice_beta_offset_div2);
+      range_in_or_return(shdr->slice_beta_offset_div2, -6, 6);
+    }
+  }
+
+  if (pps->num_slice_groups_minus1 > 0) {
+    // TODO slice groups
+    DLOG(INFO) << "Slice groups not supported";
+    return kUnsupportedStream;
+  }
+
+  shdr->header_bit_size = shdr->nalu_size * 8 - br_.NumBitsLeft();
+
+  return kOk;
+}
+
+H264Parser::Result H264Parser::ParseSEI(H264SEIMessage* sei_msg) {
+  int8 byte;
+
+  memset(sei_msg, 0, sizeof(*sei_msg));
+
+  read_bits_or_return(8, &byte);
+  while (byte == 0xff) {
+    sei_msg->type += 255;
+    read_bits_or_return(8, &byte);
+  }
+  sei_msg->type += byte;
+
+  while (byte == 0xff) {
+    sei_msg->payload_size += 255;
+    read_bits_or_return(8, &byte);
+  }
+  sei_msg->payload_size += byte;
+
+  DVLOG(4) << "Found SEI message type: " << sei_msg->type
+           << " payload size: " << sei_msg->payload_size;
+
+  switch (sei_msg->type) {
+    case kH264SEIRecoveryPoint:
+      read_ue_or_return(&sei_msg->recovery_point.recovery_frame_cnt);
+      read_bits_or_return(1, &sei_msg->recovery_point.exact_match_flag);
+      read_bits_or_return(1, &sei_msg->recovery_point.broken_link_flag);
+      read_bits_or_return(2,
+          &sei_msg->recovery_point.changing_slice_group_idc);
+      break;
+
+    default:
+      DVLOG(4) << "Unsupported SEI message";
+      break;
+  }
+
+  return kOk;
+}
+