Observe actual silent device intervals when adapting playback history

src/stream/stream_playback_audio.cpp

@@ -212,6 +212,17 @@ int64_t stream_playback_audio_pending_gain(struct stream_playback_audio* a, uint
 
 uint64_t stream_playback_audio_written(const struct stream_playback_audio* a) { return a ? a->written : 0; }
 
+int stream_playback_audio_starved(const struct stream_playback_audio* a, uint64_t played) {
+    if (!a || a->finished) return 0;
+    if (played >= a->written || !a->outputCount) return 1;
+    for (unsigned i = 0; i < a->outputCount; i++) {
+        const auto& span = a->output[(a->outputHead + i) % mapCapacity];
+        if (span.last <= played) continue;
+        return span.ptsLast == span.ptsFirst;
+    }
+    return 1;
+}
+
 void stream_playback_audio_finish(struct stream_playback_audio* a) {
     if (!a || a->finished) return;
     a->finished = true; a->stretch.flush();

src/stream/stream_playback_audio.h

@@ -26,6 +26,7 @@ int stream_playback_audio_pull(struct stream_playback_audio *audio, int16_t *pcm
 void stream_playback_audio_silence(struct stream_playback_audio *audio, unsigned frames);
 int64_t stream_playback_audio_position(struct stream_playback_audio *audio, uint64_t played_frames);
 int64_t stream_playback_audio_pending_gain(struct stream_playback_audio *audio, uint64_t played_frames);
+int stream_playback_audio_starved(const struct stream_playback_audio *audio, uint64_t played_frames);
 uint64_t stream_playback_audio_written(const struct stream_playback_audio *audio);
 void stream_playback_audio_finish(struct stream_playback_audio *audio);
 int stream_playback_audio_empty(const struct stream_playback_audio *audio);