我在Android（Jelly Bean）中使用媒体编解码器类将PCM格式编码为AAC。该文件已编码，但没有音乐播放器能够播放该文件。我无法在网上找到任何有效的代码或适当的文档。
这是我的代码：
public void doConvert()
{
new AsyncTask<Void, Void, Void>()
{
@Override
protected Void doInBackground(Void... params)
{
try
{
int codecCount = MediaCodecList.getCodecCount();
for ( int i=0; i < codecCount; i++)
{
MediaCodecInfo info = MediaCodecList.getCodecInfoAt(i);
Logger.getLogger(MainActivity.class.getSimpleName()).log(Level.INFO, info.getName());
for ( String type : info.getSupportedTypes() )
{
Logger.getLogger(MainActivity.class.getSimpleName()).log(Level.INFO, type);
}
}
File inputFile = new File( Environment.getExternalStorageDirectory().getAbsolutePath()+"/Download/Ghajini27_Mono_8Khz.wav");
//File inputFile = new File( sampleFD.get);
Log.e("File", String.valueOf(inputFile.length()));
FileInputStream fis = new FileInputStream(inputFile);
fis.skip(44);//remove wav header
File outputFile = new File( Environment.getExternalStorageDirectory().getAbsolutePath()+"/Download/out.m4a");
if ( outputFile.exists()) outputFile.delete();
FileOutputStream fos = new FileOutputStream(outputFile);
//BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(outputFile));
MediaCodec codec = MediaCodec.createEncoderByType("audio/mp4a-latm");
MediaFormat outputFormat = MediaFormat.createAudioFormat("audio/mp4a-latm", 22050, 1);
outputFormat.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC);
// outputFormat.setInteger(MediaFormat.KEY_CHANNEL_MASK, AudioFormat.CHANNEL_CONFIGURATION_MONO);
outputFormat.setInteger(MediaFormat.KEY_BIT_RATE, 22050 );
outputFormat.setInteger(MediaFormat.KEY_CHANNEL_COUNT, 1);
//outputFormat.setLong(MediaFormat.KEY_MAX_INPUT_SIZE, inputFile.length());
double durationInMs = (inputFile.length()/16000)*1000;
Log.e("duration",String.valueOf((long)durationInMs));
outputFormat.setLong(MediaFormat.KEY_DURATION, (long)durationInMs );
codec.configure(outputFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE );
codec.start();
ByteBuffer[] inputBuffers = codec.getInputBuffers();
ByteBuffer[] outputBuffer = codec.getOutputBuffers();
boolean hasMoreData = true;
MediaCodec.BufferInfo outBuffInfo = new BufferInfo();
byte readBuffer[] = new byte[48000];
byte writeBuffer[] = new byte[48000];
do
{
int nextBuffer = codec.dequeueInputBuffer(5000);
Log.e("NextBuffer","nextInputBuffer = "+nextBuffer);
if ( nextBuffer >= 0 )
{
ByteBuffer inBuf = inputBuffers[nextBuffer];
inBuf.clear();
int bytesRead = fis.read( readBuffer,0, inBuf.capacity() );
Log.e("bytesread","Read = "+bytesRead);
if ( bytesRead < inBuf.capacity() )
{
hasMoreData = false;
}
inBuf.put(readBuffer, 0, bytesRead);
codec.queueInputBuffer(nextBuffer, 0, bytesRead, 0, hasMoreData?0:MediaCodec.BUFFER_FLAG_END_OF_STREAM);
}
int outputBufferIndex = codec.dequeueOutputBuffer( outBuffInfo, 3000);
/* logger.log(Level.INFO,"nextOutputBuffer = "+outputBufferIndex);
logger.log(Level.INFO,"outBuffInfo offset = "+outBuffInfo.offset);
logger.log(Level.INFO,"outBuffInfo size = "+outBuffInfo.size);
logger.log(Level.INFO,"outBuffInfo flags = "+outBuffInfo.flags);*/
//while ( outputBufferIndex > -1 )
//{
outputBuffer[outputBufferIndex].position(outBuffInfo.offset);
outputBuffer[outputBufferIndex].get(writeBuffer,0,outBuffInfo.size);
fos.write(writeBuffer,0, outBuffInfo.size);
// logger.log(Level.INFO,"Writing = "+outBuffInfo.size+" bytes");
outputBuffer[outputBufferIndex].clear();
codec.releaseOutputBuffer(outputBufferIndex, false);
if ( outBuffInfo.flags == MediaCodec.BUFFER_FLAG_END_OF_STREAM )
{
codec.flush();
codec.stop();
codec.release();
break;
}
//outputBufferIndex = codec.dequeueOutputBuffer( outBuffInfo, 1000 );
//logger.log(Level.INFO,"nextOutputBuffer = "+outputBufferIndex);
//}
} while (outBuffInfo.flags != MediaCodec.BUFFER_FLAG_END_OF_STREAM);
fis.close();
fos.flush();
fos.close();
}
catch ( Exception e)
{
//Logger.getLogger(MainActivity.class.getSimpleName()).log(Level.INFO, "Codec Error",e);
}
//logger.log(Level.INFO,"Done");
return null;
}
}.execute();
}
答案 0 :(得分：9)
您需要为它选择一个容器。我更喜欢adts。
将有效负载数据复制到足够容纳您容器的aray中，只需添加您的位。因此，在搜索了我的解决方案之后，我将一些片段放到了适当位置
方法'fillInADTSHeader'
profile =( configParams[0]>>3 )&0x1f;
frequency_index = (this.configParams[0]&0x7) <<1 | (this.configParams[1]>>7) &0x1;
channel_config = (this.configParams[1]>>3) &0xf;
int finallength = encoded_length + 7;
ENCodedByteArray[0] = (byte) 0xff;
ENCodedByteArray[1] = (byte) 0xf1;
ENCodedByteArray[2] = (byte) ( ((profile - 1) << 6) + (frequency_index << 2) +(channel_config >> 2));
ENCodedByteArray[3] = (byte) (((channel_config & 0x3) << 6) + (finallength >> 11));
ENCodedByteArray[4] = (byte)( (finallength & 0x7ff) >> 3);
ENCodedByteArray[5] = (byte) (((finallength & 7) << 5) + 0x1f) ;
ENCodedByteArray[6] = (byte) 0xfc;
使用类似
的内容 byte chunkADTS[]=new byte[info.size + 7];
fillInADTSHeader(chunkADTS,info.size);
outputBuffers[bR].get(chunkADTS,7,info.size);
buffer.pushData(chunkADTS);
应该播放shoutcast等...
答案 1 :(得分：3)
有一个Android AAC库 https://github.com/timsu/android-aac-enc
尝试通过此库传递缓冲区。这可能有所帮助。
答案 2 :(得分：0)
你需要一个容器。将 MediaCodec 的编码输出发送到 MediaMuxer。使用 mp4 作为容器类型。无需使用@Andy--S 发布的神秘代码。
只需确保为最终文件提供扩展名 .m4a 而不是 mp4。 MP4 扩展名用于视频。
有关 MediaMuxer 的详细信息，请参阅： https://developer.android.com/reference/android/media/MediaMuxer#writeSampleData(int,%20java.nio.ByteBuffer,%20android.media.MediaCodec.BufferInfo)