1 files changed, 93 insertions, 0 deletions
diff --git a/app/src/main/java/invalid/lena/scrcpy/AudioStream.java b/app/src/main/java/invalid/lena/scrcpy/AudioStream.java
new file mode 100644
index 0000000..39b184d
--- /dev/null
+++ b/app/src/main/java/invalid/lena/scrcpy/AudioStream.java
@@ -0,0 +1,93 @@
+package invalid.lena.scrcpy;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+// Reads the scrcpy audio socket and drives an AudioFrames sink.
+//
+// Wire format (big-endian, scrcpy 3.x/4.x):
+//   1) Stream meta:    uint32 fourcc
+//                      special values 0 = disabled, 1 = error
+//   2) Loop: 12-byte frame header (uint64 ptsAndFlags | uint32 size)
+//      followed by `size` bytes of payload.
+//
+// We honour FLAG_CONFIG on the per-frame header: for opus the first
+// frame is the OpusHead (sent with FLAG_CONFIG set), subsequent are
+// opus packets. For raw PCM the server never sets FLAG_CONFIG.
+//
+// Takes a plain InputStream; caller owns stream lifecycle.
+public final class AudioStream {
+
+    private static final long FLAG_CONFIG = 1L << 62;
+
+    // Generous upper bound for one audio packet (a raw PCM block or an
+    // opus packet is a few KB). A corrupt or hostile length field must
+    // not drive the allocation below.
+    private static final int MAX_FRAME_SIZE = 1024 * 1024;
+
+    private final InputStream  source;
+    private final AudioFrames  sink;
+    private Thread             thread;
+    private volatile boolean   stop;
+
+    public AudioStream(InputStream source, AudioFrames sink) {
+        this.source = source;
+        this.sink = sink;
+    }
+
+    public void start() {
+        thread = new Thread(this::run, "audio-reader");
+        thread.start();
+    }
+
+    public void stop() {
+        stop = true;
+        if (thread != null) thread.interrupt();
+    }
+
+    public void run() {
+        try {
+            byte[] four = new byte[4];
+            Wire.readFully(source, four);
+            int fourcc = Wire.readBe32(four, 0);
+            if (fourcc == 0) {
+                Log.w("audio: server reports stream disabled (target cannot capture)");
+                return;
+            }
+            if (fourcc == 1) {
+                Log.e("audio: server reports configuration error");
+                return;
+            }
+            if (fourcc != Wire.CODEC_RAW && fourcc != Wire.CODEC_OPUS) {
+                Log.w("audio: unexpected codec %s - keeping silent",
+                        Wire.fourccName(fourcc));
+                return;
+            }
+            Log.i("audio meta codec=%s", Wire.fourccName(fourcc));
+            sink.start(fourcc);
+
+            byte[] hdr = new byte[12];
+            byte[] payload = new byte[16 * 1024];
+            long frames = 0;
+            while (!stop) {
+                Wire.readFully(source, hdr);
+                long ptsAndFlags = Wire.readBe64(hdr, 0);
+                int  size = Wire.readBe32(hdr, 8);
+                boolean cfg = (ptsAndFlags & FLAG_CONFIG) != 0;
+                if (size <= 0 || size > MAX_FRAME_SIZE) {
+                    throw new IOException("audio frame size out of range: " + size);
+                }
+                if (size > payload.length) payload = new byte[size];
+                Wire.readFully(source, payload, 0, size);
+                sink.feed(payload, 0, size, cfg);
+                if (++frames == 1) Log.i("audio frame n=1 size=%d cfg=%s", size, cfg);
+            }
+        } catch (IOException e) {
+            if (!stop) Log.e(e, "audio reader");
+        } catch (Exception e) {
+            Log.e(e, "audio reader unexpected");
+        } finally {
+            Log.i("audio reader: end");
+        }
+    }
+}