92 lines
2.9 KiB
C++
92 lines
2.9 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "media/mp4/avc.h"
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#include <algorithm>
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#include <vector>
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#include "media/mp4/box_definitions.h"
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#include "media/mp4/box_reader.h"
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namespace media {
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namespace mp4 {
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static const uint8 kAnnexBStartCode[] = {0, 0, 0, 1};
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static const int kAnnexBStartCodeSize = 4;
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static bool ConvertAVCToAnnexBInPlaceForLengthSize4(std::vector<uint8>* buf) {
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const int kLengthSize = 4;
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size_t pos = 0;
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while (pos + kLengthSize < buf->size()) {
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int nal_size = (*buf)[pos];
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nal_size = (nal_size << 8) + (*buf)[pos+1];
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nal_size = (nal_size << 8) + (*buf)[pos+2];
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nal_size = (nal_size << 8) + (*buf)[pos+3];
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std::copy(kAnnexBStartCode, kAnnexBStartCode + kAnnexBStartCodeSize,
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buf->begin() + pos);
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pos += kLengthSize + nal_size;
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}
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return pos == buf->size();
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}
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// static
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bool AVC::ConvertFrameToAnnexB(int length_size, std::vector<uint8>* buffer) {
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RCHECK(length_size == 1 || length_size == 2 || length_size == 4);
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if (length_size == 4)
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return ConvertAVCToAnnexBInPlaceForLengthSize4(buffer);
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std::vector<uint8> temp;
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temp.swap(*buffer);
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buffer->reserve(temp.size() + 32);
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size_t pos = 0;
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while (pos + length_size < temp.size()) {
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int nal_size = temp[pos];
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if (length_size == 2) nal_size = (nal_size << 8) + temp[pos+1];
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pos += length_size;
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RCHECK(pos + nal_size <= temp.size());
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buffer->insert(buffer->end(), kAnnexBStartCode,
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kAnnexBStartCode + kAnnexBStartCodeSize);
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buffer->insert(buffer->end(), temp.begin() + pos,
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temp.begin() + pos + nal_size);
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pos += nal_size;
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}
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return pos == temp.size();
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}
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// static
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bool AVC::ConvertConfigToAnnexB(
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const AVCDecoderConfigurationRecord& avc_config,
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std::vector<uint8>* buffer) {
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DCHECK(buffer->empty());
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buffer->clear();
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int total_size = 0;
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for (size_t i = 0; i < avc_config.sps_list.size(); i++)
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total_size += avc_config.sps_list[i].size() + kAnnexBStartCodeSize;
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for (size_t i = 0; i < avc_config.pps_list.size(); i++)
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total_size += avc_config.pps_list[i].size() + kAnnexBStartCodeSize;
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buffer->reserve(total_size);
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for (size_t i = 0; i < avc_config.sps_list.size(); i++) {
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buffer->insert(buffer->end(), kAnnexBStartCode,
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kAnnexBStartCode + kAnnexBStartCodeSize);
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buffer->insert(buffer->end(), avc_config.sps_list[i].begin(),
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avc_config.sps_list[i].end());
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}
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for (size_t i = 0; i < avc_config.pps_list.size(); i++) {
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buffer->insert(buffer->end(), kAnnexBStartCode,
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kAnnexBStartCode + kAnnexBStartCodeSize);
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buffer->insert(buffer->end(), avc_config.pps_list[i].begin(),
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avc_config.pps_list[i].end());
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}
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return true;
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}
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} // namespace mp4
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} // namespace media
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