ZLMediaKit/tests/Audio/SDLAudioMixer/SDLAudioDevice.cpp

#include "SDLAudioDevice.h"

#include "Util/logger.h"
using namespace std;
using namespace toolkit;

SDLAudioDevice& SDLAudioDevice::Instance() {
    static SDLAudioDevice *instance(new SDLAudioDevice);
	return *instance;
}

SDLAudioDevice::SDLAudioDevice() {
	SDL_AudioSpec wanted_spec;
	wanted_spec.freq = DEFAULT_SAMPLERATE;
	wanted_spec.format = DEFAULT_SAMPLEBIT == 16 ? AUDIO_S16 : AUDIO_S8;
	wanted_spec.channels = DEFAULT_CHANNEL;
	wanted_spec.silence = 0;
	wanted_spec.samples = DEFAULT_PCMSIZE / (DEFAULT_CHANNEL * DEFAULT_SAMPLEBIT / 8) ;
	wanted_spec.size = DEFAULT_PCMSIZE;
	wanted_spec.callback = SDLAudioDevice::onReqPCM;
	wanted_spec.userdata = this;
	if (SDL_OpenAudio(&wanted_spec, &_audioConfig)<0) {
//		throw std::runtime_error("SDL_OpenAudio failed");
        InfoL << "SDL_OpenAudio failed";
    }else{
        InfoL << "actual audioSpec: " << "freq=" << _audioConfig.freq
                                      << ",format=" << hex<<_audioConfig.format<<dec
                                      << ",channels=" << _audioConfig.channels
                                      << ",samples=" << _audioConfig.samples
                                      << ",size=" << _audioConfig.size;

    }

	_pcmBuf.reset(new char[_audioConfig.size * 10],[](char *ptr){
		delete [] ptr;
	});
}

SDLAudioDevice::~SDLAudioDevice() {
}

void SDLAudioDevice::addChannel(AudioSRC* chn) {
	lock_guard<recursive_mutex> lck(_mutexChannel);
	if(_channelSet.empty()){
        SDL_PauseAudio(0);
	}
	chn->setOutputAudioConfig(_audioConfig);
	_channelSet.emplace(chn);
}

void SDLAudioDevice::delChannel(AudioSRC* chn) {
	lock_guard<recursive_mutex> lck(_mutexChannel);
	_channelSet.erase(chn);
	if(_channelSet.empty()){
		SDL_PauseAudio(true);
	}
}

void SDLAudioDevice::onReqPCM(void* userdata, Uint8* stream, int len) {
	SDLAudioDevice *_this = (SDLAudioDevice *)userdata;
	_this->onReqPCM((char *)stream,len);
}

void SDLAudioDevice::onReqPCM(char* stream, int len) {
	lock_guard<recursive_mutex> lck(_mutexChannel);
	int size;
	int channel = 0;
	for(auto &chn : _channelSet){
		if(channel ==0 ){
			size = chn->getPCMData(_pcmBuf.get(),len);
			if(size){
                //InfoL << len << " " << size;
				memcpy(stream,_pcmBuf.get(),size);
			}
		}else{
			size = chn->getPCMData(_pcmBuf.get(),len);
			if(size){
                //InfoL << len << " " << size;
				SDL_MixAudio((Uint8*)stream,(Uint8*)_pcmBuf.get(),size,SDL_MIX_MAXVOLUME);
			}
		}
		if(size){
			channel++;
		}
	}

	if(!channel){
		memset(stream,0,len);
	}
}