Increase default audio buffer for FLAC

FLAC is not low latency: the default encoder produces blocks of 4096
samples, which represent ~85.333ms.

Increase the audio buffer by default so that audio playback works.

app/src/cli.c

@@ -2264,6 +2264,17 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
         opts->require_audio = true;
     }
 
+    if (opts->audio_playback && opts->audio_buffer == -1) {
+        // Use 50 ms audio buffer by default, but use a higher value for FLAC,
+        // which is not low latency (the default encoder produces blocks of
+        // 4096 samples, which represent ~85.333ms).
+        LOGI("FLAC audio: audio buffer increased to 120 ms (use "
+             "--audio-buffer to set a custom value)");
+        opts->audio_buffer = opts->audio_codec == SC_CODEC_FLAC
+                           ? SC_TICK_FROM_MS(120)
+                           : SC_TICK_FROM_MS(50);
+    }
+
 #ifdef HAVE_V4L2
     if (v4l2) {
         if (opts->lock_video_orientation ==

app/src/options.c

@@ -46,7 +46,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .window_height = 0,
     .display_id = 0,
     .display_buffer = 0,
-    .audio_buffer = SC_TICK_FROM_MS(50),
+    .audio_buffer = -1, // depends on the audio format,
     .audio_output_buffer = SC_TICK_FROM_MS(5),
     .time_limit = 0,
 #ifdef HAVE_V4L2