Telemetry

Scout publishes per-stream quality metrics through four optional backends. All telemetry backends require a Standard or higher license, with the exception of OTLP and Kafka which require Integration or higher.

Prometheus

Scout exposes a Prometheus-compatible metrics endpoint with per-stream quality scores, bitrate, and event counters including a VMAF score histogram.

Configuration

<Property>
  <Name>cmsdMqa.telemetry.prometheus.enabled</Name>
  <Value>true</Value>
  <Type>Boolean</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.prometheus.port</Name>
  <Value>9090</Value>
  <Type>Integer</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.prometheus.path</Name>
  <Value>/metrics</Value>
  <Type>String</Type>
</Property>

Accessing the metrics

Metrics are served at:

http://<your-server>:9090/metrics

The response uses the Prometheus text exposition format (text/plain; version=0.0.4).

Metrics reference

All per-stream metrics carry stream and rendition labels. The rendition value comes from the rendition= query parameter on segment requests; requests without it use the label value default.

Gauge metrics

Metric	Description
`cmsd_mqa_vmaf_score{stream="<name>",rendition="<id>"}`	Most recent VMAF score (0 – 100). Absent until a score is received.
`cmsd_mqa_psnr_score{stream="<name>",rendition="<id>"}`	Most recent PSNR score (dB). Absent until a score is received.
`cmsd_mqa_ssim_score{stream="<name>",rendition="<id>"}`	Most recent SSIM score (0 – 1). Absent until a score is received.
`cmsd_mqa_bitrate_bps{stream="<name>",rendition="<id>"}`	Most recently observed bitrate in bits per second.
`cmsd_mqa_keyframe_interval_ms{stream="<name>",rendition="<id>"}`	Keyframe interval in milliseconds from the most recent SEI message.

Counter metrics

Metric	Description
`cmsd_mqa_sei_messages_parsed_total{stream="<name>"}`	Running count of SVTA2128 SEI messages successfully parsed since module start.
`cmsd_mqa_headers_injected_total{stream="<name>"}`	Running count of `CMSD-Static` (and `CMSD-Dynamic`) headers injected since module start.
`cmsd_mqa_alerts_fired_total{stream="<name>"}`	Running count of quality alerts fired since module start (Enterprise only; always zero on Standard and Integration licenses).
`cmsd_mqa_frame_drops_total{stream="<name>"}`	Running count of SEI frames dropped due to parse errors or short payloads.

Histogram

Metric	Description
`cmsd_mqa_vmaf_histogram_bucket{stream="<name>",rendition="<id>",le="<bound>"}`	VMAF score distribution. Bucket boundaries: `50`, `70`, `85`, `95`, `+Inf`.
`cmsd_mqa_vmaf_histogram_count{stream="<name>",rendition="<id>"}`	Total number of VMAF score observations recorded.
`cmsd_mqa_vmaf_histogram_sum{stream="<name>",rendition="<id>"}`	Sum of all VMAF score observations.

Score sources

Prometheus metrics reflect the contents of the per-stream metrics store. Scores enter the store from two sources:

SEI ingest — SVTA2128 scores extracted from the H.264 bitstream (requires cmsdMqa.input.seiParsing=true, the default). See Media Quality Assessment (MQA).
REST ingest — scores pushed by an external tool via POST /mqa/{streamName} (requires cmsdMqa.input.restApi=true). See Media Quality Assessment (MQA).

When both sources contribute a score for the same stream, rendition, and metric, the most recently updated value is used.

Webhook

Scout can periodically push all active stream metrics as a JSON payload to a configurable HTTP endpoint.

Requires Standard or higher license.

Webhook configuration

<Property>
  <Name>cmsdMqa.telemetry.webhook.enabled</Name>
  <Value>true</Value>
  <Type>Boolean</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.webhook.url</Name>
  <Value>https://your-endpoint/metrics</Value>
  <Type>String</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.webhook.intervalMs</Name>
  <Value>5000</Value>
  <Type>Integer</Type>
</Property>

Payload format

Each push is a single HTTP POST with Content-Type: application/json:

{
  "timestamp": 1716812345678,
  "streams": [
    {
      "stream_name": "myStream",
      "rendition": "720p",
      "last_updated": 1716812344500,
      "vmaf": 87.3,
      "psnr": 42.1,
      "ssim": 0.975,
      "counters": {
        "sei_messages_parsed": 312,
        "headers_injected": 1024,
        "alerts_fired": 0
      }
    }
  ]
}

Fields present only when a score is available for that stream and rendition. Streams with no scores in the current metrics store window are omitted from the payload.

OpenTelemetry (OTLP)

Scout can export metrics to an OpenTelemetry Collector via OTLP.

Requires Integration or higher license.

OTLP configuration

<Property>
  <Name>cmsdMqa.telemetry.otlp.enabled</Name>
  <Value>true</Value>
  <Type>Boolean</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.otlp.endpoint</Name>
  <Value>http://otel-collector:4317</Value>
  <Type>String</Type>
</Property>

The transport protocol is determined automatically from the endpoint port:

Port 4317 — gRPC (OTLP/gRPC)
Port 4318 — HTTP/protobuf (OTLP/HTTP)

Metrics are exported on a 15-second interval using the OpenTelemetry SDK.

Instruments

Instrument name	Type	Description
`cmsd_mqa.vmaf_score`	Gauge	Most recent VMAF score (0 – 100).
`cmsd_mqa.psnr_score`	Gauge	Most recent PSNR score (dB).
`cmsd_mqa.ssim_score`	Gauge	Most recent SSIM score (0 – 1).
`cmsd_mqa.bitrate_bps`	Gauge	Most recently observed bitrate (bits per second).
`cmsd_mqa.sei_messages_parsed`	Counter	Cumulative SEI messages parsed.
`cmsd_mqa.headers_injected`	Counter	Cumulative CMSD headers injected.
`cmsd_mqa.alerts_fired`	Counter	Cumulative quality alerts fired (Enterprise only).

All instruments carry stream and rendition attributes.

Kafka

Scout can publish per-stream metrics to a Kafka topic.

Requires Integration or higher license.

Kafka configuration

<Property>
  <Name>cmsdMqa.telemetry.kafka.enabled</Name>
  <Value>true</Value>
  <Type>Boolean</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.kafka.brokers</Name>
  <Value>broker1:9092,broker2:9092</Value>
  <Type>String</Type>
</Property>
<Property>
  <Name>cmsdMqa.telemetry.kafka.topic</Name>
  <Value>cmsd-mqa-metrics</Value>
  <Type>String</Type>
</Property>

Message format

Messages are published every 15 seconds. Each message is a JSON object in the same format as the webhook payload (see Webhook above), with one message per publish cycle containing all active streams.

The Kafka producer uses the stream name as the message key so that all metrics for a given stream land on the same partition.

Metrics store TTL

The metrics store evicts entries that have not been updated for cmsdMqa.store.scoreTtlSeconds seconds (default: 60). This prevents the store — and therefore the Prometheus endpoint and telemetry payloads — from accumulating stale data for streams that have ended.

<Property>
  <Name>cmsdMqa.store.scoreTtlSeconds</Name>
  <Value>60</Value>
  <Type>Integer</Type>
</Property>