Terminate on controller error

This is particularly important to react to server socket disconnection
since video and audio may be disabled.

PR #4868 <https://github.com/Genymobile/scrcpy/pull/4868>

app/src/audio_player.c

@@ -66,6 +66,8 @@ static void SDLCALL
 sc_audio_player_sdl_callback(void *userdata, uint8_t *stream, int len_int) {
     struct sc_audio_player *ap = userdata;
 
+    // This callback is called with the lock used by SDL_LockAudioDevice()
+
     assert(len_int > 0);
     size_t len = len_int;
     uint32_t count = TO_SAMPLES(len);
@@ -179,19 +181,29 @@ sc_audio_player_frame_sink_push(struct sc_frame_sink *sink,
     if (written < samples) {
         uint32_t remaining = samples - written;
 
-        assert(remaining <= cap);
-        skipped_samples = sc_audiobuf_truncate(&ap->buf, cap - remaining);
+        // All samples that could be written without locking have been written,
+        // now we need to lock to drop/consume old samples
+        SDL_LockAudioDevice(ap->device);
 
-        LOGW("Audio buffer full, %" PRIu32 " samples dropped", skipped_samples);
+        // Retry with the lock
+        written += sc_audiobuf_write(&ap->buf,
+                                     swr_buf + TO_BYTES(written),
+                                     remaining);
+        if (written < samples) {
+            remaining = samples - written;
+            // Still insufficient, drop old samples to make space
+            skipped_samples = sc_audiobuf_read(&ap->buf, NULL, remaining);
+            assert(skipped_samples == remaining);
 
-        // Now there is enough space
-        uint32_t w = sc_audiobuf_write(&ap->buf,
-                                       swr_buf + TO_BYTES(written),
-                                       remaining);
-        assert(w == remaining);
-        (void) w;
+            // Now there is enough space
+            uint32_t w = sc_audiobuf_write(&ap->buf,
+                                           swr_buf + TO_BYTES(written),
+                                           remaining);
+            assert(w == remaining);
+            (void) w;
+        }
 
-        written = samples;
+        SDL_UnlockAudioDevice(ap->device);
     }
 
     uint32_t underflow = 0;
@@ -213,22 +225,30 @@ sc_audio_player_frame_sink_push(struct sc_frame_sink *sink,
 
     uint32_t can_read = sc_audiobuf_can_read(&ap->buf);
     if (can_read > max_buffered_samples) {
-        uint32_t skipped = sc_audiobuf_truncate(&ap->buf, max_buffered_samples);
-        assert(skipped);
-
-        if (played) {
-            LOGD("[Audio] Buffering threshold exceeded, skipping %" PRIu32
-                 " samples", skipped);
-#ifndef SC_AUDIO_PLAYER_NDEBUG
-        } else {
-            LOGD("[Audio] Playback not started, skipping %" PRIu32 " samples",
-                 skipped);
-#endif
-        }
-
-        skipped_samples += skipped;
+        uint32_t skip_samples = 0;
 
+        SDL_LockAudioDevice(ap->device);
         can_read = sc_audiobuf_can_read(&ap->buf);
+        if (can_read > max_buffered_samples) {
+            skip_samples = can_read - max_buffered_samples;
+            uint32_t r = sc_audiobuf_read(&ap->buf, NULL, skip_samples);
+            assert(r == skip_samples);
+            (void) r;
+            skipped_samples += skip_samples;
+        }
+        SDL_UnlockAudioDevice(ap->device);
+
+        if (skip_samples) {
+            if (played) {
+                LOGD("[Audio] Buffering threshold exceeded, skipping %" PRIu32
+                     " samples", skip_samples);
+#ifndef SC_AUDIO_PLAYER_NDEBUG
+            } else {
+                LOGD("[Audio] Playback not started, skipping %" PRIu32
+                     " samples", skip_samples);
+#endif
+            }
+        }
     }
 
     atomic_store_explicit(&ap->received, true, memory_order_relaxed);
@@ -388,7 +408,7 @@ sc_audio_player_frame_sink_open(struct sc_frame_sink *sink,
     // Use a ring-buffer of the target buffering size plus 1 second between the
     // producer and the consumer. It's too big on purpose, to guarantee that
     // the producer and the consumer will be able to access it in parallel
-    // without dropping samples.
+    // without locking.
     uint32_t audiobuf_samples = ap->target_buffering + ap->sample_rate;
 
     size_t sample_size = ap->nb_channels * ap->out_bytes_per_sample;

app/src/cli.c

@@ -2738,11 +2738,6 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
     }
 
     if (opts->record_filename) {
-        if (!opts->video && !opts->audio) {
-            LOGE("Video and audio disabled, nothing to record");
-            return false;
-        }
-
         if (!opts->record_format) {
             opts->record_format = guess_record_format(opts->record_filename);
             if (!opts->record_format) {

app/src/util/audiobuf.c

@@ -37,10 +37,10 @@ sc_audiobuf_read(struct sc_audiobuf *buf, void *to_, uint32_t samples_count) {
     assert(samples_count);
 
     uint8_t *to = to_;
-    assert(to);
 
-    // The tail cursor may be updated by the writer thread to drop samples
-    uint32_t tail = atomic_load_explicit(&buf->tail, memory_order_acquire);
+    // Only the reader thread can write tail without synchronization, so
+    // memory_order_relaxed is sufficient
+    uint32_t tail = atomic_load_explicit(&buf->tail, memory_order_relaxed);
 
     // The head cursor is updated after the data is written to the array
     uint32_t head = atomic_load_explicit(&buf->head, memory_order_acquire);
@@ -50,19 +50,21 @@ sc_audiobuf_read(struct sc_audiobuf *buf, void *to_, uint32_t samples_count) {
         samples_count = can_read;
     }
 
-    uint32_t right_count = buf->alloc_size - tail;
-    if (right_count > samples_count) {
-        right_count = samples_count;
-    }
-    memcpy(to,
-           buf->data + (tail * buf->sample_size),
-           right_count * buf->sample_size);
+    if (to) {
+        uint32_t right_count = buf->alloc_size - tail;
+        if (right_count > samples_count) {
+            right_count = samples_count;
+        }
+        memcpy(to,
+               buf->data + (tail * buf->sample_size),
+               right_count * buf->sample_size);
 
-    if (samples_count > right_count) {
-        uint32_t left_count = samples_count - right_count;
-        memcpy(to + (right_count * buf->sample_size),
-               buf->data,
-               left_count * buf->sample_size);
+        if (samples_count > right_count) {
+            uint32_t left_count = samples_count - right_count;
+            memcpy(to + (right_count * buf->sample_size),
+                   buf->data,
+                   left_count * buf->sample_size);
+        }
     }
 
     uint32_t new_tail = (tail + samples_count) % buf->alloc_size;
@@ -108,27 +110,3 @@ sc_audiobuf_write(struct sc_audiobuf *buf, const void *from_,
 
     return samples_count;
 }
-
-uint32_t
-sc_audiobuf_truncate(struct sc_audiobuf *buf, uint32_t samples_limit) {
-    for (;;) {
-        // Only the writer thread can write head, so memory_order_relaxed is
-        // sufficient
-        uint32_t head = atomic_load_explicit(&buf->head, memory_order_relaxed);
-
-        // The tail cursor is updated after the data is consumed by the reader
-        uint32_t tail = atomic_load_explicit(&buf->tail, memory_order_acquire);
-
-        uint32_t can_read = (buf->alloc_size + head - tail) % buf->alloc_size;
-        if (can_read <= samples_limit) {
-            // Nothing to truncate
-            return 0;
-        }
-
-        uint32_t skip = can_read - samples_limit;
-        uint32_t new_tail = (tail + skip) % buf->alloc_size;
-        if (atomic_compare_exchange_weak(&buf->tail, &tail, new_tail)) {
-            return skip;
-        }
-    }
-}

app/src/util/audiobuf.h

@@ -49,16 +49,6 @@ uint32_t
 sc_audiobuf_write(struct sc_audiobuf *buf, const void *from,
                   uint32_t samples_count);
 
-/**
- * Drop old samples to keep at most sample_limit samples
- *
- * Must be called by the writer thread.
- *
- * \return the number of samples dropped
- */
-uint32_t
-sc_audiobuf_truncate(struct sc_audiobuf *buf, uint32_t samples_limit);
-
 static inline uint32_t
 sc_audiobuf_capacity(struct sc_audiobuf *buf) {
     assert(buf->alloc_size);

doc/control.md

@@ -33,12 +33,6 @@ scrcpy --no-video --no-audio --keyboard=uhid
 scrcpy --no-video --no-audio -K  # short version
 ```
 
-To use AOA instead (over USB only):
-
-```bash
-scrcpy --no-video --no-audio --keyboard=aoa --mouse=aoa
-```
-
 
 ## Copy-paste
 

doc/otg.md

@@ -39,7 +39,7 @@ It only works if the device is connected over USB.
 See [FAQ](/FAQ.md#otg-issues-on-windows).
 
 
-## Control only
+## Control-only
 
 Note that the purpose of OTG is to control the device without USB debugging
 (adb).

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

@@ -48,7 +48,7 @@ public class SurfaceEncoder implements AsyncProcessor {
         this.downsizeOnError = downsizeOnError;
     }
 
-    private void streamCapture() throws IOException, ConfigurationException {
+    private void streamScreen() throws IOException, ConfigurationException {
         Codec codec = streamer.getCodec();
         MediaCodec mediaCodec = createMediaCodec(codec, encoderName);
         MediaFormat format = createFormat(codec.getMimeType(), videoBitRate, maxFps, codecOptions);
@@ -254,7 +254,7 @@ public class SurfaceEncoder implements AsyncProcessor {
             Looper.prepare();
 
             try {
-                streamCapture();
+                streamScreen();
             } catch (ConfigurationException e) {
                 // Do not print stack trace, a user-friendly error-message has already been logged
             } catch (IOException e) {