Add raw audio recorder

Add an alternative AudioRecorder to stream raw packets without encoding.

PR #3757 <Genymobile/scrcpy#3757>

Author: rom1v

server/src/main/java/com/genymobile/scrcpy/AudioCodec.java

@@ -3,6 +3,7 @@
 import android.media.MediaFormat;
 
 public enum AudioCodec implements Codec {
+    RAW(0x00_72_61_77, "raw", MediaFormat.MIMETYPE_AUDIO_RAW),
     OPUS(0x6f_70_75_73, "opus", MediaFormat.MIMETYPE_AUDIO_OPUS),
     AAC(0x00_61_61_63, "aac", MediaFormat.MIMETYPE_AUDIO_AAC);
 

server/src/main/java/com/genymobile/scrcpy/AudioRawRecorder.java

@@ -0,0 +1,75 @@
+package com.genymobile.scrcpy;
+
+import android.media.MediaCodec;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+public final class AudioRawRecorder implements AudioRecorder {
+
+    private final Streamer streamer;
+
+    private Thread thread;
+
+    private static final int READ_MS = 5; // milliseconds
+    private static final int READ_SIZE = AudioCapture.millisToBytes(READ_MS);
+
+    public AudioRawRecorder(Streamer streamer) {
+        this.streamer = streamer;
+    }
+
+    private void record() throws IOException, AudioCaptureForegroundException {
+        final ByteBuffer buffer = ByteBuffer.allocateDirect(READ_SIZE);
+        final MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
+
+        AudioCapture capture = new AudioCapture();
+        try {
+            capture.start();
+
+            streamer.writeHeader();
+            while (!Thread.currentThread().isInterrupted()) {
+                buffer.position(0);
+                int r = capture.read(buffer, READ_SIZE, bufferInfo);
+                if (r < 0) {
+                    throw new IOException("Could not read audio: " + r);
+                }
+                buffer.limit(r);
+
+                streamer.writePacket(buffer, bufferInfo);
+            }
+        } catch (Throwable e) {
+            // Notify the client that the audio could not be captured
+            streamer.writeDisableStream(false);
+            throw e;
+        } finally {
+            capture.stop();
+        }
+    }
+
+    public void start() {
+        thread = new Thread(() -> {
+            try {
+                record();
+            } catch (AudioCaptureForegroundException e) {
+                // Do not print stack trace, a user-friendly error-message has already been logged
+            } catch (IOException e) {
+                Ln.e("Audio recording error", e);
+            } finally {
+                Ln.d("Audio recorder stopped");
+            }
+        });
+        thread.start();
+    }
+
+    public void stop() {
+        if (thread != null) {
+            thread.interrupt();
+        }
+    }
+
+    public void join() throws InterruptedException {
+        if (thread != null) {
+            thread.join();
+        }
+    }
+}

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -109,9 +109,14 @@ private static void scrcpy(Options options) throws IOException, ConfigurationExc
             }
 
             if (audio) {
-                Streamer audioStreamer = new Streamer(connection.getAudioFd(), options.getAudioCodec(), options.getSendCodecId(),
-                        options.getSendFrameMeta());
-                audioRecorder = new AudioEncoder(audioStreamer, options.getAudioBitRate(), options.getAudioCodecOptions(), options.getAudioEncoder());
+                AudioCodec audioCodec = options.getAudioCodec();
+                Streamer audioStreamer = new Streamer(connection.getAudioFd(), audioCodec, options.getSendCodecId(), options.getSendFrameMeta());
+                if (audioCodec == AudioCodec.RAW) {
+                    audioRecorder = new AudioRawRecorder(audioStreamer);
+                } else {
+                    audioRecorder = new AudioEncoder(audioStreamer, options.getAudioBitRate(), options.getAudioCodecOptions(),
+                            options.getAudioEncoder());
+                }
                 audioRecorder.start();
             }