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Overview
Since build 5.2.795 it it is possible to extract raw audio data from published stream in PCM 16 bit format with a following processing on server side. For example, stream siound sound can be recorded to a file.
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To intercept raw audio data, a Java class implementing IDecodedPcmInterceptor implementing IDecodedPcmInterceptor interface should be developed. The method method pcmDecoded() of of this class will receive decoded audio packets in PCM format, as byte array. Let's take a look to class implemenr=tation implementation example to record raw audio from a stream into a WAV file:
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// Package name should be strictly defined as com.flashphoner.sdk.media package com.flashphoner.sdk.mediapcmInterceptor; // Import Flashphoner SDK packages as needed import com.flashphoner.media.rtp.recorder.OutputFileType; import com.flashphoner.media.utils.FileNameUtils; import com.flashphoner.media.utils.WaveUtil; import com.flashphoner.sdk.settingmedia.SettingsIDecodedPcmInterceptor; import com.flashphoner.mediasdk.utilssetting.FileNameUtilsSettings; import org.slf4j.Logger; import org.slf4j.LoggerFactory; // Import standard Java packages as needed import java.io.IOException; import java.io.RandomAccessFile; import java.util.Timer; import java.util.TimerTask; /** * Custom decoded audio interceptor implementation example * The example records first 10 seconds of audio track from a stream published to WAV file */ public class DecodedPcmInterceptorTest implements IDecodedPcmInterceptor{ // Will log errors to server log. private static final Logger log = LoggerFactory.getLogger("DecodedPcmInterceptorTest"); // File object to write data protected RandomAccessFile incomingRecorder; // Last audio packet timestamp private volatile long lastTs; // Sampling rate to write to a file header private int samplingRate; // Number of cahnnels to write to a file header private int numChannels; // Timer to stop recording private Timer cancelTimer; // Stream name to form file name private String streamName; public DecodedPcmInterceptorTest() { } /** * Method to handle decoded audio * @param streamName - stream name * @param pcm - decoded audio data from packet as byte array * @param samplingRate - audio track sampling rate * @param numChannels - audio track number of channels * @param timestamp - audio packet timestamp */ @Override public void pcmDecoded(String streamName, byte[] pcm, int samplingRate, int numChannels, long timestamp) { // Remember data to write to the file header updateSr(samplingRate); updateNumChannels(numChannels); // Remember the stream name and create the file to write updateStreamName(streamName); // Start timeout to stop recording startCloseTimer(); try { // Write audio data to the file recordIncoming(pcm, timestamp); } catch (IOException e) { e.printStackTrace(); } } /** * Method to start timer task which should stop recording after 10 seconds */ public void startCloseTimer() { if (cancelTimer == null) { cancelTimer = new Timer(); cancelTimer.schedule(new TimerTask() { @Override public void run() { try { close(); } catch (IOException e) { e.printStackTrace(); } } }, 10000); } } /** * Method to store audio sampling rate to write it to the file header */ public void updateSr(int samplingRate) { if (this.samplingRate == 0) { this.samplingRate = samplingRate; } } /** * Method to store audio channels number to write it to the file header */ public void updateNumChannels(int numChannels) { if (this.numChannels == 0) { this.numChannels = numChannels; } } /** * Method to store the stream name and create the file to write */ public void updateStreamName(String streamName) { if (this.streamName == null || this.streamName.isEmpty()) { // Create the file name this.streamName = FileNameUtils.adaptRecordName(streamName+".wav"); try { // Create the file and reserve header space incomingRecorder = new RandomAccessFile(Settings.RECORD.getValue()+"/"+this.streamName, "rw"); incomingRecorder.write(new byte[OutputFileType.WAV_HEADER_OFFSET]); } catch (IOException e) { log.error("Can't create DecodedPcmInterceptorTest, " + e.getMessage()); } log.info("Create DecodedPcmInterceptorTest"); } } /** * Method to write audio data to the file */ public void recordIncoming(byte[] data, long ts) throws IOException { incomingRecorder.write(data); lastTs = ts; } /** * Method to close file */ private void close() throws IOException { // Write header to the file writeHeader(); try { // Close the file incomingRecorder.close(); } catch (IOException e) { e.printStackTrace(); } log.info("Close DecodedPcmInterceptorTest"); } /** * Method to write header to the beginning of the file */ protected void writeHeader() throws IOException { // Get the file size int size = (int) incomingRecorder.length(); // Form the header byte[] header = WaveUtil.getPcmWaveHeader((size - OutputFileType.WAV_HEADER_OFFSET), samplingRate, numChannels); // Write the header to the beginning of the file incomingRecorder.seek(0); incomingRecorder.write(header); } } |
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mkdir -p com/flashphoner/sdk/mediapcmInterceptor |
and execute the command
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javac -cp /usr/local/FlashphonerWebCallServer/lib/wcs-core.jar:/usr/local/FlashphonerWebCallServer/lib/slf4j-api-1.6.4.jar ./com/flashphoner/sdk/mediapcmInterceptor/DecodedPcmInterceptorTest.java |
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jar -cf testPcmInterceptor.jar ./com/flashphoner/sdkpcmInterceptor/media/*.class |
and copy this file to WCS libraries folder
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decoded_pcm_interceptor=com.flashphoner.sdk.mediapcmInterceptor.DecodedPcmInterceptorTest record=/usr/local/FlashphonerWebCallServer/records |
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cp testlayouttestPcmInterceptor.jar /usr/local/FlashphonerWebCallServer/lib/custom |
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1. Publish a test stream in Two Way Streaming example https://test1.flashphoner.com:8444/client2/examples/demo/streaming/two_way_streaming/two_way_streaming.html, where test1.flashphoner.com is WCS server address
2. Check if WAV file existst exists in /usr/local/FlashphonerWebCallServer/records/ folder
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