Optimize ParseRbsp method in H264 bitstream parser.

webrtc/common_video/h264/h264_bitstream_parser.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "webrtc/common_video/h264/h264_bitstream_parser.h"
 
 #include <memory>
 #include <vector>
 
 #include "webrtc/base/bitbuffer.h"
-#include "webrtc/base/bytebuffer.h"
 #include "webrtc/base/checks.h"
 
 #include "webrtc/common_video/h264/h264_common.h"
 #include "webrtc/base/logging.h"
 
 namespace {
 const int kMaxAbsQpDeltaValue = 51;
 const int kMinQpValue = 0;
 const int kMaxQpValue = 51;
 }
@@ skipping 12 matching lines @@
 H264BitstreamParser::~H264BitstreamParser() {}
 
 H264BitstreamParser::Result H264BitstreamParser::ParseNonParameterSetNalu(
     const uint8_t* source,
     size_t source_length,
     uint8_t nalu_type) {
   if (!sps_ || !pps_)
     return kInvalidStream;
 
   last_slice_qp_delta_ = rtc::Optional<int32_t>();
-  std::unique_ptr<rtc::Buffer> slice_rbsp(
-      H264::ParseRbsp(source, source_length));
-  if (slice_rbsp->size() < H264::kNaluTypeSize)
+  const std::vector<uint8_t> slice_rbsp =
+      H264::ParseRbsp(source, source_length);
+  if (slice_rbsp.size() < H264::kNaluTypeSize)
     return kInvalidStream;
 
-  rtc::BitBuffer slice_reader(slice_rbsp->data() + H264::kNaluTypeSize,
-                              slice_rbsp->size() - H264::kNaluTypeSize);
+  rtc::BitBuffer slice_reader(slice_rbsp.data() + H264::kNaluTypeSize,
+                              slice_rbsp.size() - H264::kNaluTypeSize);
   // Check to see if this is an IDR slice, which has an extra field to parse
   // out.
   bool is_idr = (source[0] & 0x0F) == H264::NaluType::kIdr;
   uint8_t nal_ref_idc = (source[0] & 0x60) >> 5;
   uint32_t golomb_tmp;
   uint32_t bits_tmp;
 
   // first_mb_in_slice: ue(v)
   RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
   // slice_type: ue(v)
@@ skipping 240 matching lines @@
   const int parsed_qp = 26 + pps_->pic_init_qp_minus26 + *last_slice_qp_delta_;
   if (parsed_qp < kMinQpValue || parsed_qp > kMaxQpValue) {
     LOG(LS_ERROR) << "Parsed invalid QP from bitstream.";
     return false;
   }
   *qp = parsed_qp;
   return true;
 }
 
 }  // namespace webrtc