mirror of
https://github.com/ZLMediaKit/ZLMediaKit.git
synced 2024-11-24 19:50:38 +08:00
127 lines
4.1 KiB
C++
127 lines
4.1 KiB
C++
/*
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* Copyright (c) 2016-present The ZLMediaKit project authors. All Rights Reserved.
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*
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* This file is part of ZLMediaKit(https://github.com/ZLMediaKit/ZLMediaKit).
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*
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* Use of this source code is governed by MIT-like license that can be found in the
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* LICENSE file in the root of the source tree. All contributing project authors
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* may be found in the AUTHORS file in the root of the source tree.
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*/
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#include "AACRtp.h"
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namespace mediakit{
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bool AACRtpEncoder::inputFrame(const Frame::Ptr &frame) {
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auto ptr = (char *)frame->data() + frame->prefixSize();
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auto size = frame->size() - frame->prefixSize();
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auto remain_size = size;
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auto max_size = getRtpInfo().getMaxSize() - 4;
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while (remain_size > 0) {
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if (remain_size <= max_size) {
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outputRtp(ptr, remain_size, size, true, frame->dts());
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break;
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}
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outputRtp(ptr, max_size, size, false, frame->dts());
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ptr += max_size;
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remain_size -= max_size;
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}
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return true;
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}
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void AACRtpEncoder::outputRtp(const char *data, size_t len, size_t total_len, bool mark, uint64_t stamp) {
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auto rtp = getRtpInfo().makeRtp(TrackAudio, nullptr, len + 4, mark, stamp);
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auto payload = rtp->data() + RtpPacket::kRtpTcpHeaderSize + RtpPacket::kRtpHeaderSize;
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payload[0] = 0;
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payload[1] = 16;
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payload[2] = ((total_len) >> 5) & 0xFF;
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payload[3] = ((total_len & 0x1F) << 3) & 0xFF;
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memcpy(payload + 4, data, len);
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RtpCodec::inputRtp(std::move(rtp), false);
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}
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/////////////////////////////////////////////////////////////////////////////////////
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AACRtpDecoder::AACRtpDecoder() {
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obtainFrame();
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}
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void AACRtpDecoder::obtainFrame() {
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//从缓存池重新申请对象，防止覆盖已经写入环形缓存的对象
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_frame = FrameImp::create();
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_frame->_codec_id = CodecAAC;
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}
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bool AACRtpDecoder::inputRtp(const RtpPacket::Ptr &rtp, bool key_pos) {
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auto payload_size = rtp->getPayloadSize();
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if (payload_size <= 0) {
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// 无实际负载
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return false;
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}
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auto stamp = rtp->getStampMS();
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// rtp数据开始部分
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auto ptr = rtp->getPayload();
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// rtp数据末尾
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auto end = ptr + payload_size;
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// 首2字节表示Au-Header的个数，单位bit，所以除以16得到Au-Header个数
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auto au_header_count = ((ptr[0] << 8) | ptr[1]) >> 4;
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if (!au_header_count) {
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// 问题issue: https://github.com/ZLMediaKit/ZLMediaKit/issues/1869
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WarnL << "invalid aac rtp au_header_count";
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return false;
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}
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// 记录au_header起始指针
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auto au_header_ptr = ptr + 2;
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ptr = au_header_ptr + au_header_count * 2;
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if (end < ptr) {
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// 数据不够
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return false;
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}
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if (!_last_dts) {
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// 记录第一个时间戳
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_last_dts = stamp;
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}
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// 每个audio unit时间戳增量
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auto dts_inc = static_cast<int64_t>(stamp - _last_dts) / au_header_count;
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if (dts_inc < 0 || dts_inc > 100) {
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// 时间戳增量异常，忽略
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dts_inc = 0;
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}
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for (auto i = 0u; i < (size_t)au_header_count; ++i) {
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// 之后的2字节是AU_HEADER,其中高13位表示一帧AAC负载的字节长度，低3位无用
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auto size = ((au_header_ptr[0] << 8) | au_header_ptr[1]) >> 3;
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auto len = std::min<int>(size, end - ptr);
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if (len <= 0) {
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break;
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}
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_frame->_buffer.append((char *)ptr, len);
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ptr += len;
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au_header_ptr += 2;
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if (_frame->size() >= (size_t)size) {
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// 设置当前audio unit时间戳
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_frame->_dts = _last_dts + i * dts_inc;
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flushData();
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}
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}
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// 记录上次时间戳
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_last_dts = stamp;
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return false;
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}
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void AACRtpDecoder::flushData() {
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auto ptr = reinterpret_cast<const uint8_t *>(_frame->data());
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if ((ptr[0] == 0xFF && (ptr[1] & 0xF0) == 0xF0) && _frame->size() > ADTS_HEADER_LEN) {
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// adts头打入了rtp包，不符合规范，兼容EasyPusher的bug
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_frame->_prefix_size = ADTS_HEADER_LEN;
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}
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RtpCodec::inputFrame(_frame);
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obtainFrame();
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}
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}//namespace mediakit
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