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// 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.
#include "media/mp4/avc.h"
#include <algorithm>
#include <vector>
#include "media/mp4/box_definitions.h"
#include "media/mp4/box_reader.h"
namespace media {
namespace mp4 {
static const uint8 kAnnexBStartCode[] = {0, 0, 0, 1};
static const int kAnnexBStartCodeSize = 4;
static bool ConvertAVCToAnnexBInPlaceForLengthSize4(std::vector<uint8>* buf) {
const int kLengthSize = 4;
size_t pos = 0;
while (pos + kLengthSize < buf->size()) {
int nal_size = (*buf)[pos];
nal_size = (nal_size << 8) + (*buf)[pos+1];
nal_size = (nal_size << 8) + (*buf)[pos+2];
nal_size = (nal_size << 8) + (*buf)[pos+3];
std::copy(kAnnexBStartCode, kAnnexBStartCode + kAnnexBStartCodeSize,
buf->begin() + pos);
pos += kLengthSize + nal_size;
}
return pos == buf->size();
}
// static
bool AVC::ConvertFrameToAnnexB(int length_size, std::vector<uint8>* buffer) {
RCHECK(length_size == 1 || length_size == 2 || length_size == 4);
if (length_size == 4)
return ConvertAVCToAnnexBInPlaceForLengthSize4(buffer);
std::vector<uint8> temp;
temp.swap(*buffer);
buffer->reserve(temp.size() + 32);
size_t pos = 0;
while (pos + length_size < temp.size()) {
int nal_size = temp[pos];
if (length_size == 2) nal_size = (nal_size << 8) + temp[pos+1];
pos += length_size;
RCHECK(pos + nal_size <= temp.size());
buffer->insert(buffer->end(), kAnnexBStartCode,
kAnnexBStartCode + kAnnexBStartCodeSize);
buffer->insert(buffer->end(), temp.begin() + pos,
temp.begin() + pos + nal_size);
pos += nal_size;
}
return pos == temp.size();
}
// static
bool AVC::ConvertConfigToAnnexB(
const AVCDecoderConfigurationRecord& avc_config,
std::vector<uint8>* buffer) {
DCHECK(buffer->empty());
buffer->clear();
int total_size = 0;
for (size_t i = 0; i < avc_config.sps_list.size(); i++)
total_size += avc_config.sps_list[i].size() + kAnnexBStartCodeSize;
for (size_t i = 0; i < avc_config.pps_list.size(); i++)
total_size += avc_config.pps_list[i].size() + kAnnexBStartCodeSize;
buffer->reserve(total_size);
for (size_t i = 0; i < avc_config.sps_list.size(); i++) {
buffer->insert(buffer->end(), kAnnexBStartCode,
kAnnexBStartCode + kAnnexBStartCodeSize);
buffer->insert(buffer->end(), avc_config.sps_list[i].begin(),
avc_config.sps_list[i].end());
}
for (size_t i = 0; i < avc_config.pps_list.size(); i++) {
buffer->insert(buffer->end(), kAnnexBStartCode,
kAnnexBStartCode + kAnnexBStartCodeSize);
buffer->insert(buffer->end(), avc_config.pps_list[i].begin(),
avc_config.pps_list[i].end());
}
return true;
}
} // namespace mp4
} // namespace media
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