Synthetic source¶

The syntetic input is a built-in test signal generator: SMPTE bars with a running clock and a tone. It needs no external data and serves install verification, debugging, and load testing.

Configuration¶

The generator emits uncompressed frames (raw YUV and PCM). This is deliberate: the raw signal can be sent losslessly straight to SDI. To serve the stream over network protocols (and get the codec/quality variants you need), pair the generator with a transcoder:

streams:
  syn:
    inputs:
    - syntetic: {}
    transcoder:
      output:
      - source: !content video
        codec: !set h264
      - source: !content audio
        codec: !set aac
    segments: 6

Without a transcoder section the stream carries raw frames: a regular player cannot play it, but this is exactly the stream you need for SDI output.

Generator parameters (all optional, syntetic: {} gives a demo signal):

    - syntetic:
        video: !video
          rate:
            numerator: 30000     # fractional frame rates (NTSC) are supported
            denominator: 1001
        audio: !audio
          sample_rate: 48000
          channels: 2

Timecode in the picture¶

Each frame's PTS is drawn into the luma band of the image and can be machine-read back. This makes it possible to measure end-to-end latency and find lost frames from the picture itself — handy when debugging the transcoder and protocols.

Next steps¶

• Transcoding
• Channel from a file