如何在两个音频文件在机器人彼此的顶部相结合 [英] How to combine two audio files on top of each other in android
问题描述
我有2个音频文件。第一是背景音乐和第二个是一个讲话。 (他们每个人都在约4分钟长度)
I have 2 audio files. the first is background music and the second is a speech. (Each of them is about 4 minutes in length)
现在我想将它们混合并获得4分钟的演讲用的背景音乐。
Now I want to mix them and receive a 4 minute speech with a background music.
推荐答案
您不需要FFmpeg中,可以使用现有的标准codeCS在android系统。
You don't need FFMPEG, you can use the standard codecs available in android.
public void playFile(String fileToPlay)
{
// see where we find a suitable autiotrack
MediaExtractor extractor = new MediaExtractor();
try
{
extractor.setDataSource(fileToPlay);
}
catch (IOException e)
{
out.release();
return;
}
extractor.selectTrack(0);
String fileType=typeForFile(fileToPlay);
if (fileType==null)
{
out.release();
extractor.release();
return;
}
MediaCodec codec = MediaCodec.createDecoderByType(fileType);
MediaFormat wantedFormat=extractor.getTrackFormat(0);
codec.configure(wantedFormat,null,null,0);
codec.start();
ByteBuffer[] inputBuffers = codec.getInputBuffers();
ByteBuffer[] outputBuffers = codec.getOutputBuffers();
// Allocate our own buffer
int maximumBufferSizeBytes = 0;
for(ByteBuffer bb:outputBuffers)
{
int c=bb.capacity();
if (c>maximumBufferSizeBytes) maximumBufferSizeBytes=c;
}
setupBufferSizes(maximumBufferSizeBytes/4);
final MediaCodec.BufferInfo bufferInfo=new MediaCodec.BufferInfo();
MediaFormat format=null;
while(true)
{
long timeoutUs=1000000;
int inputBufferIndex = codec.dequeueInputBuffer(timeoutUs);
if (inputBufferIndex >= 0)
{
ByteBuffer targetBuffer = inputBuffers[inputBufferIndex];
int read = extractor.readSampleData(targetBuffer, 0);
int flags=extractor.getSampleFlags();
if (read>0)
codec.queueInputBuffer(inputBufferIndex, 0,read, 0, flags);
else
codec.queueInputBuffer(inputBufferIndex, 0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
extractor.advance();
}
int outputBufferIndex = codec.dequeueOutputBuffer(bufferInfo,timeoutUs);
if (outputBufferIndex >= 0)
{
final boolean last = bufferInfo.flags == MediaCodec.BUFFER_FLAG_END_OF_STREAM;
int s=bufferInfo.size/4;
ByteBuffer bytes=outputBuffers[outputBufferIndex];
((ByteBuffer)bytes.position(bufferInfo.offset)).asShortBuffer().get(shorts,0,s*2);
process(shorts,0,s*2);
codec.releaseOutputBuffer(outputBufferIndex, false);
if (last)
break;
}
else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED)
{
outputBuffers = codec.getOutputBuffers();
}
else if (outputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED)
{
format = codec.getOutputFormat();
}
}
extractor.release();
codec.stop();
codec.release();
1文件看完上面的code交易。的进程例程(其尚未定义)接收采样的交错阵列(左/右/左/右/左/右)。所有你现在需要做的就是添加这些渠道的目标缓冲区。例如
The above code deals with the reading of 1 file. The 'process' routine (which isn't defined yet) receives an interleaved array of samples (left/right/left/right/left/right). All you need to do now is add these channels to a target buffer. E.g
short[] target=new short[LENGTH OF 4 MINUTES];
int idx=0;
process(short[] audio, int l)
{
for(int i=0;i<l;i++)
target[idx++]+=audio[i]/2;
}
然后将得到的目标阵列包含您的覆盖样本。
The resulting target array contains then your overlaid samples.
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