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Interlaced output

media.transcode.interlace

Sapsan encodes interlaced H.264 for broadcast receivers that need 1080i or 576i. This output track uses source frames before deinterlacing.

Configuration

Apply the stream configuration through central. This example creates an interlaced H.264 video track at 1080 lines and preserves the source audio track. The source must have a suitable frame rate.

streams:
  - name: tv1
    inputs:
    - udp: {host: 239.0.0.1, port: 5000}
    transcoder:
      hardware: cpu
      output:
      - source: !content video
        codec: !set h264
        bitrate: 6000000
        params: !video
          interlace: true
          resize: !fit
            height: 1080
      - source: !content audio
        codec: same

In the central console, open the Transcoder tab, click More on the rendition, and enable Interlaced output.

Behavior and constraints

  • Field order — Interlaced input retains its field order. Progressive input without field order is encoded bottom-field-first.
  • Field processing — Resizing and color conversion process each field separately. For a 4:2:0 source whose height is not divisible by 4, fields cannot split equally: the whole frame is processed with the warning interlaced source cannot be split into fields.
  • Mixed ladder — The interlaced track receives frames before filtering; progressive tracks receive them afterward. transcoder.decoder.deinterlace affects only progressive outputs.

Only H.264 on CPU is supported. Output height must be divisible by 4. Without resizing, source height is used and checked at startup. Interlaced uncompressed input is not yet supported for this encoding.

Verification

After applying the configuration, check that the transcoder is running and the output track has the required height and interlaced format. Check field order and smooth motion on the target receiver. Configuration errors appear when saving; startup errors appear in transcoder status.