【OC】预置音效

1. 创建handle

音效初始化过程内部进行一些buffer的申请。

SAMICore_BinaryContextCreateParameter *create_param = [[SAMICore_BinaryContextCreateParameter alloc] init];
create_param.sampleRate = sample_rate;
create_param.numChannel = num_channels;
create_param.maxBlockSize = block_size;
create_param.type = SAMICore_BinaryType::SAMICore_BinaryTypeFile;
create_param.data = (void*)res_path.c_str();
int ret = 0;
SAMICore *sami_core_handle = [[SAMICore alloc] initWithIdentify:SAMICore_Identify_Processor_ContextWithBinaryRes  param:create_param result:&ret];
if(ret != SAMI_OK) {
    std::cerr << "create handler failed: " << ret;
    exit(-1);
}

2.初始化buffer

//初始化处理buffer
SAMICore_AudioBuffer *in_audio_buffer = [[SAMICore_AudioBuffer alloc] init];
in_audio_buffer.numberChannels = num_channels;
in_audio_buffer.numberSamples = block_size;
in_audio_buffer.data = new float*[num_channels];
in_audio_buffer.isInterleave = 0;

SAMICore_AudioBuffer *out_audio_buffer = [[SAMICore_AudioBuffer alloc] init];
out_audio_buffer.numberChannels = num_channels;
out_audio_buffer.numberSamples = block_size;
out_audio_buffer.data = new float*[num_channels];
out_audio_buffer.isInterleave = 0;

for(int c = 0; c < int(num_channels); ++c) {
    ((float**)in_audio_buffer.data)[c] = new float[block_size];
    ((float**)out_audio_buffer.data)[c] = new float[block_size];
}

SAMICore_AudioBlock *in_block = [[SAMICore_AudioBlock alloc] init];
in_block.dataType = SAMICore_DataType_AudioBuffer;
in_block.numberAudioData = 1;
in_block.audioData = in_audio_buffer;

SAMICore_AudioBlock *out_block = [[SAMICore_AudioBlock alloc] init];
out_block.dataType = SAMICore_DataType_AudioBuffer;
out_block.numberAudioData = 1;
out_block.audioData = out_audio_buffer;

3.处理数据

for(; inx + block_size < (int)num_frames;) {
    for(auto c = 0u; c < num_channels; ++c) {
        std::copy_n(in_samples[c].data() + inx, block_size, ((float**)in_audio_buffer.data)[c]);
    }

    ret = [sami_core_handle processWithInBlock:in_block outBlock:out_block];
    if(ret != SAMI_OK) { std::cerr << "ret: " << ret << std::endl; }
    inx += block_size;
}

4.动态更新配置

预置音效的使用场景一般是在k歌场景，需要实时更新配置，sdk提供了动态更新的接口，接口保证了线程安全，可在不同于process的线程更新，并且内部做了平滑处理。

SAMICore_BinaryContextUpdateParameter *updateParameter = [[SAMICore_BinaryContextUpdateParameter alloc] init];
updateParameter.type = SAMICore_BinaryTypeFile;
updateParameter.data = (void*)another_res_path.c_str();

SAMICore_Property* update_property = [[SAMICore_Property alloc] init];
update_property.data = updateParameter;
update_property.type = SAMICore_DataType_ResourceParameter;

ret = [sami_core_handle setProperty:update_property withId:SAMICore_PropertyId_Processor_ContextUpdateFromBinaryFile];
if(ret != SAMI_OK) {
    cout << "sami_core update data error:" << ret << endl;
    return 0;
}
changed_effect = true;

5.释放handle

sami_core_handle = nil;