Stream

The stream command is the per-viewer half of the proxy pipeline: it runs once for every connected TV, reads the local segments produced by the shared segmenter (or playout) process, and sends the result to that viewer. That's why its input is a local file path, not the upstream URL — the upstream is handled by the segmenter.

Because it runs per viewer, this is the place for cheap per-viewer processing. The default just repackages the video without re-encoding; transcoding here would run once per TV, so heavy work belongs in the segmenter or playout command instead.

Contract

• Input: {{ .Stream.PlaylistPath }} — path to the local HLS playlist written by the segmenter/playout process.
• Output: video stream data on stdout. stderr is printed to the debug logs. If the command exits with empty stdout, an upstream error is triggered.

YAML Structure

proxy:
  stream:
    command: []
    template_variables: []
    env_variables: []

Fields

Field	Type	Required	Description
command	Command	No	Stream command. See Command.
template_variables	[]NameValue	No	User variables available in the command. See Command.
env_variables	[]NameValue	No	Environment variables for the command.

The stream command receives the reserved variable {{ .Stream.PlaylistPath }} (the local HLS playlist) — see Command → Reserved Variables.

Default Template Variables

These variables are used by the default command and can be overridden:

Variable	Default	Description
ffmpeg_log_level	fatal	ffmpeg -v log level

Examples

Basic FFmpeg Remuxing

Repackage the local segments without re-encoding (the default behavior):

proxy:
  stream:
    command:
      [ffmpeg, -v, error, -i, "{{ .Stream.PlaylistPath }}", -c, copy, -f, mpegts, "pipe:1"]

Transcoding with Custom Preset

Re-encode per viewer (heavier — prefer transcoding in the segmenter instead):

proxy:
  stream:
    command:
      [ffmpeg, -v, "{{ .ffmpeg_log_level }}", -i, "{{ .Stream.PlaylistPath }}",
       -c:v, libx264, -preset, ultrafast, -c:a, aac, -f, mpegts, "pipe:1"]
    template_variables:
      - { name: ffmpeg_log_level, value: error }

With Environment Variables

Pass configuration to a wrapper script via the environment:

proxy:
  stream:
    command: [/opt/scripts/stream.sh, "{{ .Stream.PlaylistPath }}"]
    env_variables:
      - { name: STREAM_QUALITY, value: high }
      - { name: LOG_DIR, value: /var/log/streams }