#835:

* auto-tune the av-sync latency based on the sound codec
* expose the values via xpra info

git-svn-id: https://xpra.org/svn/Xpra/trunk@9381 3bb7dfac-3a0b-4e04-842a-767bc560f471

src/xpra/server/source.py

@@ -213,6 +213,7 @@ def __init__(self, protocol, disconnect_cb, idle_add, timeout_add, source_remove
         self.sound_sink = None
         self.av_sync = av_sync
         self.av_sync_delay = 0
+        self.av_sync_delay_total = 0
 
         self.server_core_encodings = core_encodings
         self.server_encodings = encodings
@@ -614,7 +615,7 @@ def parse_batch_int(value, varname):
         self.set_av_sync_delay(int(self.av_sync and av_sync) * c.intget("av-sync.delay.default", 150))
         soundlog("pulseaudio id=%s, server=%s, sound decoders=%s, sound encoders=%s, receive=%s, send=%s",
                  self.pulseaudio_id, self.pulseaudio_server, self.sound_decoders, self.sound_encoders, self.sound_receive, self.sound_send)
-        avsynclog("av-sync: server=%s, client=%s, delay=%s", self.av_sync, av_sync, self.av_sync_delay)
+        avsynclog("av-sync: server=%s, client=%s, total=%s", self.av_sync, av_sync, self.av_sync_delay_total)
 
         log("cursors=%s, bell=%s, notifications=%s", self.send_cursors, self.send_bell, self.send_notifications)
         log("client uuid %s", self.uuid)
@@ -820,6 +821,7 @@ def new_stream(self, sound_source, codec):
                       {"start-of-stream"    : True,
                        "codec"              : sound_source.codec,
                        "sequence"           : sound_source.sequence})
+        self.update_av_sync_delay_total()
 
     def new_sound_buffer(self, sound_source, data, metadata):
         soundlog("new_sound_buffer(%s, %s, %s) suspended=%s",
@@ -955,10 +957,24 @@ def sink_clean():
     def set_av_sync_delay(self, v):
         #update all window sources with the given delay
         assert self.av_sync, "av-sync is not enabled"
-        self.av_sync_delay = min(1000, max(0, int(v) + AV_SYNC_DELTA))
-        avsynclog("av-sync set to %ims (from value=%s and delta=%s)", self.av_sync_delay, v, AV_SYNC_DELTA)
+        self.av_sync_delay = v
+        self.update_av_sync_delay_total()
+
+    def update_av_sync_delay_total(self):
+        encoder_latency = 0
+        ss = self.sound_source
+        if ss:
+            try:
+                from xpra.sound.gstreamer_util import ENCODER_LATENCY
+                encoder_latency = ENCODER_LATENCY.get(ss.codec, 0)
+                avsynclog("encoder_latency(%s)=%s", ss.codec, encoder_latency)
+            except Exception as e:
+                encoder_latency = 0
+                avsynclog("failed to get encoder latency for %s: %s", ss.codec, e)
+        self.av_sync_delay_total = min(1000, max(0, int(self.av_sync_delay) + AV_SYNC_DELTA + encoder_latency))
+        avsynclog("av-sync set to %ims (from client queue latency=%s, encoder latency=%s, env delta=%s)", self.av_sync_delay_total, self.av_sync_delay, encoder_latency, AV_SYNC_DELTA)
         for ws in self.window_sources.values():
-            ws.av_sync_delay = v
+            ws.av_sync_delay = self.av_sync_delay_total
 
 
     def set_screen_sizes(self, screen_sizes):
@@ -1187,7 +1203,9 @@ def up(prefix, d):
         up("encoding",      self.default_encoding_options)
         up("encoding",      self.encoding_options)
         up("connection",    self.protocol.get_info())
-        up("av-sync",       {"delay"        :self.av_sync_delay})
+        up("av-sync",       {"client.delay"         : self.av_sync_delay,
+                             "total"                : self.av_sync_delay_total,
+                             "delta"                : AV_SYNC_DELTA})
         info.update(self.get_sound_info())
         info.update(self.get_features_info())
         info.update(self.get_screen_info())

src/xpra/sound/gstreamer_util.py

@@ -86,9 +86,27 @@ def get_queue_time(default_value=450, prefix=""):
             ]
 CODECS = {}
 
+#these encoders require an "audioconvert" element:
 ENCODER_NEEDS_AUDIOCONVERT = ("flacenc", )
-
-CODEC_ORDER = [MP3, WAVPACK, WAV, FLAC, SPEEX, OPUS]
+#options we use to tune for low latency:
+ENCODER_DEFAULT_OPTIONS = {
+            "lamemp3enc"    : {"encoding-engine-quality": 0},   #"fast"
+            "wavpackenc"    : {"mode" : 1},     #"fast" (0 aka "very fast" is not supported)
+            "flacenc"       : {"quality" : 0},  #"fast"
+            "opusenc"       : {"cbr" : 0,
+                               "complexity" : 0},
+           }
+#based on the encoder options above:
+ENCODER_LATENCY = {
+        MP3         : 250,
+        FLAC        : 150,
+        WAV         : 0,
+        WAVPACK     : 600,
+        OPUS        : 500,
+        SPEEX       : 500,
+       }
+
+CODEC_ORDER = [FLAC, MP3, WAVPACK, WAV] #, SPEEX, OPUS, VORBIS, AAC]
 #CODEC_ORDER = [MP3, FLAC, SPEEX]