streaming/backend

Install and configure nginx to act as a streaming backend server.

Tasks

Everything is in the tasks/main.yml file.

Available variables

Main variables are:

• debian_version: Codename of the version of Debian used.

• streaming.backend.data_root: nginx data_root.

• streaming.adaptive: configuration of HLS encoding variants

  • video_codec: HLS video codec. Should probably be libx264

  • audio_codec: HLS audio codec. Should probably be aac

  • variants: a description of all the variants. Should be an object; each attribute is another object with the below items. The name of the attribute will be used as the name of the stream.

    • hls_bandwidth: the bandwidth as configured in the HLS manifest

    • video_bitrate: the video bitrate as passed to ffmpeg

    • audio_bitrate: the audio bitrate as passed to ffmpeg

    • extra_settings: any extra settings to pass to ffmpeg for this video stream

    • width: the width of this stream, used for scaling (height is computed)

• streaming.hq_config: configuration of main HLS variant

  • keyframe_period: how much time (in seconds) between key frames for the HLS stream

  • width: width (in pixels) of the source video stream

  • hls_bandwidth: the bandwidth of the “source” video stream as it will be stored in the HLS manifest

  • video_bitrate: the bitrate for the “source” video stream as passed to ffmpeg for transcoding

  • audio_bitrate: the bitrate for the “source” audio stream as passed to ffmpeg for transcoding

• streaming.dash: configuration of DASH encoding variants

  • video_codec: the video codec for streams in the DASH manifest (e.g., libsvtav1 for AV1)

  • audio_codec: the audio codec for streams in the DASH manifest (e.g., ‘libopus’ for Opus)

  • preset: the parameter used for the -preset parameter to ffmpeg (e.g., 8 for AV1 without dropping frames on modern hardware)

  • video_variants: an array of objects. Each object can have the following attributes, all of which are optional (in which case the relevant parameter is not passed to ffmpeg):

    • crf: the value of the -crf parameter passed to ffmpeg for that stream (e.g., 23)

    • scale: the value of the -s parameter passed to ffmpeg for that stream (e.g., 640x360 to scale a 720p video to half resolution)

    • bitrate: the value of the -b parameter passed to ffmpeg for that stream

    • maxrate: the value of the -maxrate parameter passed to ffmpeg for that stream

  • audio_variants: and array of objects. Same system as for video_variants, except that only one object parameter is supported: bitrate, for the audio bit rate for that alternative.

• streaming.backend.server_name: The FQDN of your backend streaming server.

• streaming.rooms: List. The name of the different rooms you are recording in. This will end up in the URL of the stream available.

• streaming.youtube_stream_keys: Optional, a dictionary of room names to youtube streaming keys. The stream will be mirrored to YouTube.

Other variables used are:

• letsencrypt_well_known_dir: Directory where to store the /.well-known/ data for the Let’s Encrypt challenge.

• skip_unit_test: Used internally by the test suite to disable actions that can’t be performed in the gitlab-ci test runner.