Fix freeze YouTube al cambio punteggio: PNG atomica e relay stabile

rsvg scrive su .tmp poi rename; il feeder ignora PNG parziali.
YouTube relay: no doppio avvio, reconnect RTMP; overlay restart solo dopo 3 miss.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/services/streams/overlay/refresh.rb

@@ -37,10 +37,12 @@ module Streams
       end
 
       def render_png!(svg_path, png_path)
-        unless system("rsvg-convert", "-w", "1280", "-h", "720", "-o", png_path.to_s, svg_path.to_s, out: File::NULL, err: File::NULL)
+        tmp = "#{png_path}.tmp"
+        unless system("rsvg-convert", "-w", "1280", "-h", "720", "-o", tmp, svg_path.to_s, out: File::NULL, err: File::NULL)
           raise Error, "rsvg-convert fallito per session #{@session.id}"
         end
 
+        File.rename(tmp, png_path)
         FileUtils.touch(png_path)
       end
     end

backend/app/services/streams/overlay_relay.rb

@@ -86,8 +86,15 @@ module Streams
         end
 
         if running?(session.id)
-          Rails.logger.warn("[OverlayRelay] _air non attivo, restart session=#{session.id}")
+          misses = redis.incr(overlay_air_miss_key(session.id)).to_i
+          redis.expire(overlay_air_miss_key(session.id), 120)
+          return if misses < 3
+
+          redis.del(overlay_air_miss_key(session.id))
+          Rails.logger.warn("[OverlayRelay] _air non attivo dopo #{misses} tentativi, restart session=#{session.id}")
           stop(session)
+        else
+          redis.del(overlay_air_miss_key(session.id))
         end
 
         start(session)
@@ -181,6 +188,10 @@ module Streams
         redis.get(format(REDIS_KEY, session_id))
       end
 
+      def overlay_air_miss_key(session_id)
+        format("overlay_relay:air_miss:%s", session_id)
+      end
+
       def process_alive?(pid)
         Process.kill(0, pid.to_i)
         true

backend/app/services/streams/youtube_relay.rb

@@ -12,6 +12,8 @@ module Streams
         return if session.stream_key.blank?
         return if session.terminal?
 
+        return pid_for(session.id).to_i if running?(session.id)
+
         stop(session) if pid_for(session.id).present?
 
         log_path = log_file(session)
@@ -80,6 +82,7 @@ module Streams
           "-fflags", "+genpts+discardcorrupt", "-use_wallclock_as_timestamps", "1",
           "-analyzeduration", "10000000", "-probesize", "10000000",
           "-rw_timeout", "15000000",
+          "-reconnect", "1", "-reconnect_at_eof", "1", "-reconnect_streamed", "1", "-reconnect_delay_max", "5",
           "-i", intake,
           "-f", "lavfi", "-i", "anullsrc=channel_layout=mono:sample_rate=48000",
           "-map", "0:v:0", "-map", "1:a:0",

backend/bin/overlay_png_feeder.rb

@@ -16,13 +16,24 @@ trap("TERM") { stop = true }
 trap("INT") { stop = true }
 
 # image2pipe richiede frame continui: inviamo la PNG a ritmo fisso ( anche se invariata ).
+last_bytes = nil
 File.open(pipe_path, "wb") do |pipe|
   loop do
     break if stop
 
     if File.exist?(png_path)
-      pipe.write(File.binread(png_path))
+      bytes = File.binread(png_path)
+      # Evita frame corrotti durante rsvg-convert (file parziale prima del rename atomico).
+      next if bytes.bytesize < 512
+
+      if bytes != last_bytes
+        pipe.write(bytes)
         pipe.flush
+        last_bytes = bytes
+      elsif last_bytes
+        pipe.write(last_bytes)
+        pipe.flush
+      end
     end
 
     sleep poll_sec