用xugler实现java音频转换
我正在尝试用Java中的Xuggler将aac/wav/wma音频文件转换为mp3
不幸的是,我的质量损失很大。我的输入文件大小约为7MB,输出文件大小仅为1,5MB
采样率设置为44100 Hz,是否有其他参数需要设置
谢谢你的回答
if (args.length <= 1)
throw new IllegalArgumentException("must pass an input filename and output filename as argument");
IMediaWriter writer = ToolFactory.makeWriter(args[1]);
String filename = args[0];
// Create a Xuggler container object
IContainer container = IContainer.make();
// Open up the container
if (container.open(filename, IContainer.Type.READ, null) < 0)
throw new IllegalArgumentException("could not open file: " + filename);
// query how many streams the call to open found
int numStreams = container.getNumStreams();
// and iterate through the streams to find the first audio stream
int audioStreamId = -1;
IStreamCoder audioCoder = null;
for(int i = 0; i < numStreams; i++)
{
// Find the stream object
IStream stream = container.getStream(i);
// Get the pre-configured decoder that can decode this stream;
IStreamCoder coder = stream.getStreamCoder();
if (coder.getCodecType() == ICodec.Type.CODEC_TYPE_AUDIO)
{
audioStreamId = i;
audioCoder = coder;
audioCoder.setBitRate(container.getBitRate());
break;
}
}
if (audioStreamId == -1)
throw new RuntimeException("could not find audio stream in container: "+filename);
/* We read only AAC file for the moment */
if(audioCoder.getCodecID() != ICodec.ID.CODEC_ID_AAC
&& audioCoder.getCodecID() != ICodec.ID.CODEC_ID_WAVPACK
&& audioCoder.getCodecID() != ICodec.ID.CODEC_ID_WMAV1
&& audioCoder.getCodecID() != ICodec.ID.CODEC_ID_WMAV2
&& audioCoder.getCodecID() != ICodec.ID.CODEC_ID_WMAPRO
&& audioCoder.getCodecID() != ICodec.ID.CODEC_ID_WMAVOICE)
{
System.out.println("Read only AAC, WAV or WMA files");
System.exit(1);
}
audioCoder.setSampleFormat(IAudioSamples.Format.FMT_S16);
/*
* Now we have found the audio stream in this file. Let's open up our decoder so it can
* do work.
*/
if (audioCoder.open() < 0)
throw new RuntimeException("could not open audio decoder for container: "+filename);
int streamIndex = writer.addAudioStream(0, 0, audioCoder.getChannels(), audioCoder.getSampleRate());
System.out.println("audio Frame size : "+audioCoder.getAudioFrameSize());
/*
* Now, we start walking through the container looking at each packet.
*/
IPacket packet = IPacket.make();
while(container.readNextPacket(packet) >= 0)
{
/*
* Now we have a packet, let's see if it belongs to our audio stream
*/
if (packet.getStreamIndex() == audioStreamId)
{
/*
* We allocate a set of samples with the same number of channels as the
* coder tells us is in this buffer.
*
* We also pass in a buffer size (1024 in our example), although Xuggler
* will probably allocate more space than just the 1024 (it's not important why).
*/
IAudioSamples samples = IAudioSamples.make(512, audioCoder.getChannels(),IAudioSamples.Format.FMT_S16 );
/*
* A packet can actually contain multiple sets of samples (or frames of samples
* in audio-decoding speak). So, we may need to call decode audio multiple
* times at different offsets in the packet's data. We capture that here.
*/
int offset = 0;
/*
* Keep going until we've processed all data
*/
while(offset < packet.getSize())
{
int bytesDecoded = audioCoder.decodeAudio(samples, packet, offset);
if (bytesDecoded < 0)
throw new RuntimeException("got error decoding audio in: " + filename);
offset += bytesDecoded;
/*
* Some decoder will consume data in a packet, but will not be able to construct
* a full set of samples yet. Therefore you should always check if you
* got a complete set of samples from the decoder
*/
if (samples.isComplete())
{
writer.encodeAudio(streamIndex, samples);
}
}
}
else
{
/*
* This packet isn't part of our audio stream, so we just silently drop it.
*/
do {} while(false);
}
}
# 1 楼答案
当心当你有一个带封面的mp3(png)时,你可能会因为试图将视频png流发送到音频流而出错。。通过使用ISamples并通过if(packet.getStreamIndex()==audioStreamId){}读取数据包,可以更好地控制所使用的流。 检查我的完整代码:
# 2 楼答案
我会这样做:
输入是要转换的文件(aac/wav/wma),输出是新文件。mp3文件(Xugler通过扩展名计算转换)
您可以提高质量,增加kbps(即,对于320 kbps,您需要通过320000)
希望有帮助:-)
仅供参考:对于Java项目,如果尚未导入,则需要导入以下内容:
# 3 楼答案
我不确定具体的选项和它们的作用,但看看javadoc for IStreamCoder。你可能还想玩其他各种选择。如果想要完全控制,甚至可以使用
setFlags()
方法直接在ffmpeg上设置标志(Xugler在下面使用)