Module device_profile 

Device-profile policy: turning what a device reports about its audio output into the constraints we send Jellyfin.

The platform layer reports raw facts (what MediaCodecList enumerates, how many channels the current audio route accepts); deciding what those facts mean for a DeviceProfile is domain logic and lives here, on the Rust side of the boundary, where it is testable without a device.

Constants

EXTERNAL_SUBTITLE_FORMATS 🔒

Subtitle formats we can render ourselves, delivered as an external sidecar track rather than painted into the video.

FALLBACK_AUDIO_CHANNELS 🔒

Channel count assumed when the platform cannot tell us — every audio route can voice stereo, so it is the only safe floor.

FALLBACK_AUDIO_CODEC 🔒

The codec claimed when a device reports nothing we can use. Every renderer decodes AAC, and claiming something is what makes the server transcode to it rather than give up.

MAX_SUPPORTED_AUDIO_CHANNELS 🔒

Upper bound we are willing to claim. Jellyfin profiles top out at 7.1, and a nonsense reading from a driver should not become a nonsense profile.

NO_SUBTITLE_STREAM

Jellyfin’s sentinel for “negotiate no subtitle stream at all”.

SUBTITLE_QUERY_KEYS 🔒

Query keys through which a stream URL can carry a subtitle decision.

WEBVIEW_AUDIO_CODECS 🔒

Audio codecs the webview’s <video> element can decode.

Functions

audio_forces_transcode

Decide whether we must transcode regardless of what the server negotiated, given the source’s audio streams as (codec, is_default) in source order.

clamp_max_audio_channels

Decide the MaxAudioChannels to advertise, given what the current audio route reported.

max_audio_channels

The channel cap for this device, reading the platform’s report where one exists.

playback_subtitle_stream_index

The SubtitleStreamIndex to negotiate with: always “none”.

served_audio_codec

The codec of the audio track the server will actually serve, given the source’s audio streams as (codec, is_default) in source order: the default, or the first when none is marked.

subtitle_forces_burn_in

Whether asking the server to serve this subtitle codec forces it to burn the subtitle into the picture.

subtitle_profiles

The SubtitleProfile entries to advertise, as (format, method).

subtitle_supports_external_delivery

Whether a subtitle in this format can reach the app as a sidecar it draws itself — the same verdict as subtitle_forces_burn_in, from the reader’s side, and the one a subtitle picker needs.

video_audio_codecs

Narrow a detected audio-codec list to what the renderer that will actually play the video can decode.

webview_can_decode_audio

Whether the webview <video> element can decode this audio codec.

without_server_chosen_subtitle

Rewrite a stream URL so it asks for no subtitle, whoever built it.