avc.cc revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "media/formats/mp4/avc.h"
6
7#include <algorithm>
8#include <vector>
9
10#include "media/formats/mp4/box_definitions.h"
11#include "media/formats/mp4/box_reader.h"
12
13namespace media {
14namespace mp4 {
15
16static const uint8 kAnnexBStartCode[] = {0, 0, 0, 1};
17static const int kAnnexBStartCodeSize = 4;
18
19static bool ConvertAVCToAnnexBInPlaceForLengthSize4(std::vector<uint8>* buf) {
20  const int kLengthSize = 4;
21  size_t pos = 0;
22  while (pos + kLengthSize < buf->size()) {
23    int nal_size = (*buf)[pos];
24    nal_size = (nal_size << 8) + (*buf)[pos+1];
25    nal_size = (nal_size << 8) + (*buf)[pos+2];
26    nal_size = (nal_size << 8) + (*buf)[pos+3];
27    std::copy(kAnnexBStartCode, kAnnexBStartCode + kAnnexBStartCodeSize,
28              buf->begin() + pos);
29    pos += kLengthSize + nal_size;
30  }
31  return pos == buf->size();
32}
33
34// static
35bool AVC::ConvertFrameToAnnexB(int length_size, std::vector<uint8>* buffer) {
36  RCHECK(length_size == 1 || length_size == 2 || length_size == 4);
37
38  if (length_size == 4)
39    return ConvertAVCToAnnexBInPlaceForLengthSize4(buffer);
40
41  std::vector<uint8> temp;
42  temp.swap(*buffer);
43  buffer->reserve(temp.size() + 32);
44
45  size_t pos = 0;
46  while (pos + length_size < temp.size()) {
47    int nal_size = temp[pos];
48    if (length_size == 2) nal_size = (nal_size << 8) + temp[pos+1];
49    pos += length_size;
50
51    RCHECK(pos + nal_size <= temp.size());
52    buffer->insert(buffer->end(), kAnnexBStartCode,
53                   kAnnexBStartCode + kAnnexBStartCodeSize);
54    buffer->insert(buffer->end(), temp.begin() + pos,
55                   temp.begin() + pos + nal_size);
56    pos += nal_size;
57  }
58  return pos == temp.size();
59}
60
61// static
62bool AVC::ConvertConfigToAnnexB(
63    const AVCDecoderConfigurationRecord& avc_config,
64    std::vector<uint8>* buffer) {
65  DCHECK(buffer->empty());
66  buffer->clear();
67  int total_size = 0;
68  for (size_t i = 0; i < avc_config.sps_list.size(); i++)
69    total_size += avc_config.sps_list[i].size() + kAnnexBStartCodeSize;
70  for (size_t i = 0; i < avc_config.pps_list.size(); i++)
71    total_size += avc_config.pps_list[i].size() + kAnnexBStartCodeSize;
72  buffer->reserve(total_size);
73
74  for (size_t i = 0; i < avc_config.sps_list.size(); i++) {
75    buffer->insert(buffer->end(), kAnnexBStartCode,
76                kAnnexBStartCode + kAnnexBStartCodeSize);
77    buffer->insert(buffer->end(), avc_config.sps_list[i].begin(),
78                avc_config.sps_list[i].end());
79  }
80
81  for (size_t i = 0; i < avc_config.pps_list.size(); i++) {
82    buffer->insert(buffer->end(), kAnnexBStartCode,
83                   kAnnexBStartCode + kAnnexBStartCodeSize);
84    buffer->insert(buffer->end(), avc_config.pps_list[i].begin(),
85                   avc_config.pps_list[i].end());
86  }
87  return true;
88}
89
90}  // namespace mp4
91}  // namespace media
92