Optimize ParseRbsp method in H264 bitstream parser.

webrtc/common_video/h264/sps_vui_rewriter.cc

 /*
  *  Copyright (c) 2016 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/sps_vui_rewriter.h"
 
 #include <algorithm>
 #include <memory>
+#include <vector>
 
 #include "webrtc/base/bitbuffer.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/logging.h"
 
 #include "webrtc/common_video/h264/h264_common.h"
 #include "webrtc/common_video/h264/sps_parser.h"
 
 namespace webrtc {
 
@@ skipping 41 matching lines @@
 bool CopyRemainingBits(rtc::BitBuffer* source,
                        rtc::BitBufferWriter* destination);
 
 SpsVuiRewriter::ParseResult SpsVuiRewriter::ParseAndRewriteSps(
     const uint8_t* buffer,
     size_t length,
     rtc::Optional<SpsParser::SpsState>* sps,
     rtc::Buffer* destination) {
   // Create temporary RBSP decoded buffer of the payload (exlcuding the
   // leading nalu type header byte (the SpsParser uses only the payload).
-  std::unique_ptr<rtc::Buffer> rbsp_buffer = H264::ParseRbsp(buffer, length);
-  rtc::BitBuffer source_buffer(rbsp_buffer->data(), rbsp_buffer->size());
+  std::vector<uint8_t> rbsp_buffer = H264::ParseRbsp(buffer, length);
+  rtc::BitBuffer source_buffer(rbsp_buffer.data(), rbsp_buffer.size());
   rtc::Optional<SpsParser::SpsState> sps_state =
       SpsParser::ParseSpsUpToVui(&source_buffer);
   if (!sps_state)
     return ParseResult::kFailure;
 
   *sps = sps_state;
 
   if (sps_state->pic_order_cnt_type >= 2) {
     // No need to rewrite VUI in this case.
     return ParseResult::kPocOk;
   }
 
   // We're going to completely muck up alignment, so we need a BitBuffer to
   // write with.
   rtc::Buffer out_buffer(length + kMaxVuiSpsIncrease);
   rtc::BitBufferWriter sps_writer(out_buffer.data(), out_buffer.size());
 
   // Check how far the SpsParser has read, and copy that data in bulk.
   size_t byte_offset;
   size_t bit_offset;
   source_buffer.GetCurrentOffset(&byte_offset, &bit_offset);
-  memcpy(out_buffer.data(), rbsp_buffer->data(),
+  memcpy(out_buffer.data(), rbsp_buffer.data(),
          byte_offset + (bit_offset > 0 ? 1 : 0));  // OK to copy the last bits.
 
   // SpsParser will have read the vui_params_present flag, which we want to
   // modify, so back off a bit;
   if (bit_offset == 0) {
     --byte_offset;
     bit_offset = 7;
   } else {
     --bit_offset;
   }
@@ skipping 242 matching lines @@
     size_t count = std::min(static_cast<size_t>(32u),
                             static_cast<size_t>(source->RemainingBitCount()));
     COPY_BITS(source, destination, bits_tmp, count);
   }
   // TODO(noahric): The last byte could be all zeroes now, which we should just
   // strip.
   return true;
 }
 
 }  // namespace webrtc