ZLMediaKit/src/Extension/G711.cpp

73 lines
2.0 KiB
C++

/*
* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
*
* This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
*
* Use of this source code is governed by MIT license that can be found in the
* LICENSE file in the root of the source tree. All contributing project authors
* may be found in the AUTHORS file in the root of the source tree.
*/
#include "G711.h"
using namespace std;
using namespace toolkit;
namespace mediakit{
/**
* G711类型SDP
*/
class G711Sdp : public Sdp {
public:
/**
* G711采样率固定为8000
* @param codecId G711A G711U
* @param payload_type rtp payload type
* @param sample_rate 音频采样率
* @param channels 通道数
* @param bitrate 比特率
*/
G711Sdp(CodecId codecId, int payload_type, int sample_rate, int channels, int bitrate)
: Sdp(sample_rate, payload_type) {
_printer << "m=audio 0 RTP/AVP " << payload_type << "\r\n";
if (bitrate) {
_printer << "b=AS:" << bitrate << "\r\n";
}
_printer << "a=rtpmap:" << payload_type << " " << getCodecName(codecId) << "/" << sample_rate << "/" << channels << "\r\n";
}
string getSdp() const override {
return _printer;
}
private:
_StrPrinter _printer;
};
Track::Ptr G711Track::clone() const {
return std::make_shared<G711Track>(*this);
}
Sdp::Ptr G711Track::getSdp(uint8_t payload_type) const {
if (!ready()) {
WarnL << getCodecName() << " Track未准备好";
return nullptr;
}
const auto codec = getCodecId();
const auto sample_rate = getAudioSampleRate();
const auto audio_channel = getAudioChannel();
const auto bitrate = getBitRate() >> 10;
if (sample_rate == 8000 && audio_channel == 1) {
// https://datatracker.ietf.org/doc/html/rfc3551#section-6
payload_type = (codec == CodecG711U) ? Rtsp::PT_PCMU : Rtsp::PT_PCMA;
}
return std::make_shared<G711Sdp>(codec, payload_type, sample_rate, audio_channel, bitrate);
}
}//namespace mediakit