Generic telemetry

src/README.md

@@ -262,7 +262,7 @@ Startup order is:
 
 If DeckLink discovery or output setup fails, the app logs a warning and continues running without starting the output scheduler or scheduled playback. This keeps render cadence, runtime shader testing, HTTP state, and logging available on machines without DeckLink hardware or drivers.
 
-`/api/state` reports the output status in `videoIO.statusMessage`.
+`/api/state` reports backend-neutral output status in `videoOutput`. Portable fields live at `videoOutput.enabled`, `videoOutput.backend`, and `videoOutput.scheduleFailures`; backend-specific counters such as DeckLink buffered depth and schedule lead live under `videoOutput.backendMetrics`. The older `videoIO` and `decklink` status objects are retained for compatibility while clients migrate.
 
 ## Optional DeckLink Input
 

src/control/RuntimeStateJson.h

@@ -27,7 +27,7 @@ struct RuntimeStateJsonInput
 inline void WriteVideoIoStatusJson(JsonWriter& writer, const RuntimeStateJsonInput& input)
 {
 	writer.BeginObject();
-	writer.KeyString("backend", "decklink");
+	writer.KeyString("backend", input.config.videoOutputBackend);
 	writer.KeyNull("modelName");
 	writer.KeyBool("supportsInternalKeying", false);
 	writer.KeyBool("supportsExternalKeying", false);
@@ -38,6 +38,47 @@ inline void WriteVideoIoStatusJson(JsonWriter& writer, const RuntimeStateJsonInp
 	writer.EndObject();
 }
 
+inline void WriteVideoOutputBackendMetricsJson(JsonWriter& writer, const RuntimeStateJsonInput& input)
+{
+	writer.BeginObject();
+	if (input.config.videoOutputBackend == "decklink")
+	{
+		writer.KeyBool("bufferedAvailable", input.telemetry.deckLinkBufferedAvailable);
+		writer.Key("buffered");
+		if (input.telemetry.deckLinkBufferedAvailable)
+			writer.UInt(input.telemetry.deckLinkBuffered);
+		else
+			writer.Null();
+		writer.KeyDouble("scheduleCallMs", input.telemetry.deckLinkScheduleCallMilliseconds);
+		writer.KeyBool("scheduleLeadAvailable", input.telemetry.deckLinkScheduleLeadAvailable);
+		writer.Key("scheduleLeadFrames");
+		if (input.telemetry.deckLinkScheduleLeadAvailable)
+			writer.Int(input.telemetry.deckLinkScheduleLeadFrames);
+		else
+			writer.Null();
+		writer.KeyUInt("playbackFrameIndex", input.telemetry.deckLinkPlaybackFrameIndex);
+		writer.KeyUInt("nextScheduleFrameIndex", input.telemetry.deckLinkNextScheduleFrameIndex);
+		writer.KeyInt("playbackStreamTime", input.telemetry.deckLinkPlaybackStreamTime);
+		writer.KeyUInt("scheduleRealignments", input.telemetry.deckLinkScheduleRealignments);
+	}
+	writer.EndObject();
+}
+
+inline void WriteVideoOutputTelemetryJson(JsonWriter& writer, const RuntimeStateJsonInput& input)
+{
+	writer.BeginObject();
+	writer.KeyBool("enabled", input.videoOutputEnabled);
+	writer.KeyString("backend", input.config.videoOutputBackend);
+	writer.KeyString("statusMessage", input.videoOutputStatus);
+	writer.KeyUInt("scheduleFailures", input.telemetry.scheduleFailures);
+	writer.KeyUInt("completions", input.telemetry.completions);
+	writer.KeyUInt("late", input.telemetry.displayedLate);
+	writer.KeyUInt("dropped", input.telemetry.dropped);
+	writer.Key("backendMetrics");
+	WriteVideoOutputBackendMetricsJson(writer, input);
+	writer.EndObject();
+}
+
 inline void OutputDimensions(const RuntimeStateJsonInput& input, unsigned& width, unsigned& height)
 {
 	VideoFormatDimensions(input.config.outputVideoFormat, width, height);
@@ -277,6 +318,8 @@ inline std::string RuntimeStateToJson(const RuntimeStateJsonInput& input)
 	writer.KeyString("modeName", input.config.outputVideoFormat + " output-only");
 	writer.EndObject();
 
+	writer.Key("videoOutput");
+	WriteVideoOutputTelemetryJson(writer, input);
 	writer.Key("decklink");
 	WriteVideoIoStatusJson(writer, input);
 	writer.Key("videoIO");