Generated background music: music: %{elevenlabs: "prompt"} composes a
track with the ElevenLabs Music API
and the result then goes through the normal music pipeline (loop/trim,
fades, ducking; see PhxDemo.Render).
use PhxDemo.Case,
music: %{elevenlabs: "calm lo-fi piano, soft drums", length_ms: 30_000}Or pick a preset (see presets/0):
use PhxDemo.Case, music: %{elevenlabs: :lofi}Keys (atom or string):
:elevenlabs: a prompt string, or a preset name such as:lofi(required). A string that equals a preset name is the preset, so presets survive the round trip throughtimeline.json.:length_ms: track length, 3_000 to 600_000 (default 30_000). A track shorter than the video loops, so a short one is fine.:instrumental: no vocals (defaulttrue):model_id: e.g."music_v1"(default: the API's default):output_format: an MP3 format, default"mp3_44100_128"
The API key comes from the ELEVENLABS_API_KEY environment variable, or
config :phx_demo, :elevenlabs_api_key, "...". It is never put in the
settings, so it never reaches timeline.json.
The track is cached under <output_dir>/.tts_cache, keyed on the prompt and
options, so re-recording an unchanged demo makes no API call.
Summary
Functions
Cache key for a normalized spec.
Pre-flight for generated music. Returns :ok when music isn't generated,
otherwise validates the setting and checks that an API key is available.
settings is a map with atom or string keys. Option :api_key overrides
the lookup (for testing).
Like check/2, raising PhxDemo.Env.Error.
Generates the track into cache_dir (or reuses the cached one). Returns
{:ok, path} or {:error, message}. Options: :api_key, :base_url,
:http (a 3-arity fun like PhxDemo.HTTP.post_json/3, for tests).
Whether a music: value asks for generated music.
The full prompt for a preset, or nil when name (atom or string) isn't one.
The built-in presets: name to prompt. Each prompt also gets a shared suffix
asking for steady, vocal-free background music (see preset_prompt/1).
The JSON request body for a normalized spec.
Normalizes a generated music: value into a map with atom keys and
defaults filled in. Returns {:ok, spec} or {:error, message}.
Functions
Cache key for a normalized spec.
Pre-flight for generated music. Returns :ok when music isn't generated,
otherwise validates the setting and checks that an API key is available.
settings is a map with atom or string keys. Option :api_key overrides
the lookup (for testing).
Like check/2, raising PhxDemo.Env.Error.
Generates the track into cache_dir (or reuses the cached one). Returns
{:ok, path} or {:error, message}. Options: :api_key, :base_url,
:http (a 3-arity fun like PhxDemo.HTTP.post_json/3, for tests).
Whether a music: value asks for generated music.
iex> PhxDemo.MusicGen.generated?(%{elevenlabs: "lo-fi"})
true
iex> PhxDemo.MusicGen.generated?(%{"elevenlabs" => "lo-fi"})
true
iex> PhxDemo.MusicGen.generated?("song.mp3")
falseThe full prompt for a preset, or nil when name (atom or string) isn't one.
iex> PhxDemo.MusicGen.preset_prompt(:lofi) =~ "lo-fi hip hop"
true
iex> PhxDemo.MusicGen.preset_prompt("lofi") == PhxDemo.MusicGen.preset_prompt(:lofi)
true
iex> PhxDemo.MusicGen.preset_prompt("calm piano")
nilThe built-in presets: name to prompt. Each prompt also gets a shared suffix
asking for steady, vocal-free background music (see preset_prompt/1).
The JSON request body for a normalized spec.
Normalizes a generated music: value into a map with atom keys and
defaults filled in. Returns {:ok, spec} or {:error, message}.