linux上的java声音：如何从TargetDataLine中快速捕获到足以跟上？

我正在使用Java声音API和Java 1.7.当我在Linux上运行我的应用程序时,我很难快速地从TargetDataline读取以跟上记录的内容(java版“1.7.0_51”,Java(TM)SE运行时环境(版本1.7.0_51-b13),Java HotSpot(TM)64位服务器VM(构建24.51-b03,混合模式),Red Hat Enterprise linux 5).在我的windows 7笔记本电脑上运行相同的程序时,我没有这个问题.我有点难过.

为了隔离这个问题,我编写了一个程序,它从TargetDataline中捕获一段时间(交互式确定)并记录每次在固定字节数的阻塞读取中花费的时间,然后将它们与平均值一起打印出来读取时间,已用时间和捕获的音频时间.

我的测试程序如下：

import java.io.BufferedReader;import java.io.IOException;import java.io.inputStreamReader;import java.util.ArrayList;import java.util.linkedList;import java.util.List;import javax.sound.sampled.AudioFormat;import javax.sound.sampled.AudioSystem;import javax.sound.sampled.Dataline;import javax.sound.sampled.lineUnavailableException;import javax.sound.sampled.mixer;import javax.sound.sampled.TargetDataline;/** * This is a test of mic capture delay for given buffer and fetch settings. */public class MicCaptureDelayTest {   /**    * the audio format used for capturing and transmitting    */   private static final AudioFormat format =         new AudioFormat(8000,16,1,true,true);   /**    * This is the target data line buffer size to request,in bytes.    */   private static final int MIC_BUFFER_SIZE = 1000;   /**    * This is the number of bytes to try to fetch from the target data line at a    * time.    */   private static final int MIC_FETCH_SIZE = 480;   /**    * Searches for available mixers on the system that have a microphone.    * @return a List of matching mixers    */   private static List

当我在linux环境中运行时,大约10秒钟的录音,输出如下：

Starting.StopPing.read times (ms): 54.00  18.10  36.62  36.32  35.99  18.10  18.25  54.26  18.30  35.56  18.12  35.51  36.74  17.22  36.70  35.29  18.33  35.60  18.23  54.72  19.00  37.99  18.14  18.37  53.91  18.37  35.34  36.00  18.00  36.00  18.00  54.71  17.22  18.12  36.18  36.64  36.08  18.00  54.34  18.26  18.27  35.44  18.30  54.77  18.33  18.24  36.51  35.47  36.52  18.35  17.14  54.96  18.13  36.73  17.21  54.95  18.28  18.37  36.54  36.72  35.56  18.37  17.23  54.46  18.36  35.53  18.08  36.00  36.00  17.99  54.30  18.06  35.22  18.00  18.00  53.93  18.32  35.63  36.64  18.16  35.21  18.30  55.65  18.23  18.35  35.55  36.32  35.60  18.30  36.33  36.21  17.22  36.54  18.32  54.96  17.19  18.36  35.62  36.67  35.25  18.29  18.37  54.63  18.37  36.54  18.35  53.91  18.37  17.23  36.70  36.09  36.01  17.19  18.33  53.91  18.37  36.56  18.36  35.53  36.58  18.16  53.84  18.26  36.03  18.0818.12  54.24  18.08  36.14  36.1918.12  36.08  18.11  53.80  18.2818.37  36.55  18.13  53.99  18.0036.12  35.54  18.28  36.56  17.2053.96  18.00  18.01  36.67  36.5336.71  17.19  18.37  54.37  18.0235.97  18.00  54.00  18.00  18.0036.00  35.99  36.34  18.37  18.3553.93  18.13  36.63  18.33  36.3336.34  18.33  36.55  35.51  36.6618.29  18.06  54.00  17.99  36.0818.25  36.64  36.38  18.37  35.5536.66  18.21  36.73  17.19  54.2718.13  35.55  18.18  36.31  35.5618.34  53.90  18.36  18.09  36.1518.22  53.90  18.32  18.37  53.8918.19  36.04  17.20  53.94  18.3118.37  36.55  36.70  36.61  18.3517.18  53.97  18.32  36.55  19.0118.99  57.00  18.99  38.01  18.9838.00  18.99  36.99  36.35  18.3736.55  36.70  18.04  38.00  19.0038.00  37.99  18.99  37.99  19.0037.06  36.43  36.03  18.00  18.0054.47  18.25  36.70  18.22  18.3753.55  18.33  35.59  36.59  18.2935.36  18.37  54.89  18.24  36.4418.33  18.36  53.52  18.13  36.3635.57  18.20  35.52  18.20  53.7818.18  18.16  35.49  36.67  36.5418.37  36.53  36.67  17.19  36.6518.29  54.87  17.14  18.24  36.6835.49  35.61  18.27  18.36  53.7718.24  35.43  18.35  53.90  18.3718.24  38.00  38.00  37.99  18.9919.01  37.98  19.00  57.00  18.9919.00  38.00  18.99  55.01  18.9835.99  18.00  18.01  54.98  18.0037.00  17.99  36.00  36.00  17.9954.01  18.98  18.00  36.02  18.9853.16  18.34  35.59  36.20  17.9836.00  18.00  54.00  17.99  18.0036.00  35.99  36.01  17.99  18.0054.00  17.98  35.99  18.00  54.28Mean read time (ms): 30.210176811594206Time captured (s): 10.35Time elapsed (s): 10.466399

在我的windows环境中类似大约10秒录制的输出如下所示：

Starting.StopPing.read times (ms):44.96  30.13  29.97  29.97  30.0429.96  29.96  30.00  29.99  30.0029.92  30.01  30.02  30.01  29.9929.85  45.12  30.03  29.92  29.9629.98  30.00  29.98  30.00  0.2444.73  29.94  30.04  29.96  29.8629.96  30.05  29.85  30.17  30.0230.00  29.94  29.99  29.99  30.0429.97  44.99  29.99  30.08  29.8830.05  29.95  29.97  29.87  0.1544.95  29.98  29.91  30.08  29.9830.00  30.01  29.96  29.94  30.0430.01  29.96  29.88  30.00  29.9530.04  44.99  29.99  29.96  30.0330.00  30.07  29.94  30.01  0.2144.77  29.95  30.02  30.01  30.0029.96  29.98  30.00  30.00  29.9429.99  30.04  29.93  29.99  30.0229.98  44.99  29.99  29.96  30.0130.03  29.95  30.00  29.97  0.2144.81  29.88  30.05  29.99  29.9930.01  29.97  29.99  29.99  29.9829.99  30.00  29.97  29.98  29.9730.01  44.95  29.97  30.03  30.0030.00  30.00  29.99  29.97  0.2144.79  29.95  30.00  29.99  29.9529.98  29.93  30.06  29.94  30.0829.97  30.00  29.97  29.99  29.9829.94  45.05  30.04  29.91  30.0029.99  29.97  30.01  29.98  0.2144.79  29.94  29.99  29.89  30.0630.03  29.96  30.04  29.98  29.9030.04  30.00  29.98  30.00  29.9730.07  44.96  29.98  29.93  30.0729.98  29.90  30.00  29.94  0.1344.97  29.98  29.99  29.94  30.0230.00  29.93  29.99  30.02  30.0129.99  29.96  30.02  29.90  29.9330.01  45.04  30.06  29.99  29.9829.94  30.04  30.00  29.92  0.2044.83  29.94  29.99  30.00  30.0130.02  29.87  30.03  29.94  30.0329.99  30.00  30.07  29.90  29.9530.05  44.97  30.01  29.98  29.9730.01  29.99  30.00  29.97  0.2144.77  29.96  30.00  30.03  29.9130.00  30.01  30.03  29.93  29.9829.99  29.99  29.93  30.04  30.0430.01  44.92  30.04  29.97  29.9130.08  29.89  29.97  29.88  0.1545.01  30.09  29.89  30.01  30.0129.97  29.95  29.96  30.05  30.0429.88  30.00  29.99  29.94  30.0529.98  44.99  30.01  30.00  29.9929.95  30.00  29.88  30.11  0.2144.78  30.01  29.96  29.99  29.9829.98  29.99  30.01  29.91  29.8230.10  29.99  30.15  29.96  29.9329.98  45.05  29.97  29.99  30.0229.96  29.98  29.95  30.04  0.2144.74  30.02  29.97  29.97  30.0329.99  29.93  29.94  30.07  29.9929.99  29.94  30.02  29.97  29.9030.01  45.12  29.91  30.03  29.9530.03  29.97  29.87  30.09  0.2044.79  29.98  29.97  29.99  30.0130.01  29.97  29.99  29.99  30.0129.99  29.94  30.01  30.00  29.9829.98  45.02  29.97  29.91  30.0629.99  29.96  30.02  29.98Mean read time (ms): 30.073811959885386Time captured (s): 10.47Time elapsed (s): 10.777957116

linux环境的摘要统计信息,大约30秒的记录：

Mean read time (ms): 30.152922254616133Time captured (s): 30.87Time elapsed (s): 31.135111

windows环境的摘要统计信息,大约30秒记录：

Mean read time (ms): 30.020078674852652Time captured (s): 30.54Time elapsed (s): 30.901762071

我注意到,经过的时间和捕获的时间之间的差异随着linux端记录时间的增加而增加.在linux方面,单个获取时间看起来也不那么规律.

我已经尝试调整缓冲区和获取大小,但我还没有找到一个允许从线路中快速获取的组合.

什么可能导致取得缓慢？如何确定合理的提取和缓冲区大小,以便具有低延迟但快速提取以及时跟上实时？ linux上是否存在可能影响此问题或我应该检查的声音配置问题？

谢谢！

private static final int MIC_FETCH_SIZE = 480; // 0.12 seconds of data 

private static final int MIC_FETCH_SIZE = 32000; // 2 seconds of data