media/mp4/avc.cc

   1 // Copyright (c) 2012 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/mp4/avc.h"
   6
   7 #include <algorithm>
   8 #include <vector>
   9
  10 #include "media/mp4/box_definitions.h"
  11 #include "media/mp4/box_reader.h"
  12
  13 namespace media {
  14 namespace mp4 {
  15
  16 static const uint8 kAnnexBStartCode[] = {0, 0, 0, 1};
  17 static const int kAnnexBStartCodeSize = 4;
  18
  19 static 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
  35 bool 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
  62 bool 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