feat: add per-input volume control and fader level to audiomixer (#396)

[Ulrond]

Summary

Adds two mechanisms for per-input audio level control on the AudioMixer, addressing gaps identified from the dsAudio.h gap analysis (raised by @BatthalaH).

Per-input volume methods (IAudioMixerController)

• setInputVolume(int inputIndex, int volume) — set volume (0-100) for a specific mixer input
• getInputVolume(int inputIndex) — query current volume for an input

Covers: TTS attenuation, system sound levels, audio description level adjustment.

Fader property (Property.aidl)

• Property.FADER_LEVEL = 5 — main/associated audio balance (0=main only, 50=equal, 100=assoc only)

Platform-dependent — must be declared in hfp-audiomixer.yaml. Reference HFP updated for mixer instance 0.

Files changed

• IAudioMixerController.aidl — added setInputVolume() and getInputVolume() methods
• Property.aidl — added FADER_LEVEL property
• hfp-audiomixer.yaml — added FADER_LEVEL to mixer 0 supported properties

Closes #396

See also: discussion #398 (output port lifecycle rationale)

[rdkcmf-jenkins]

b'## Copyright scan failure
Commit: 39de011
Report detail: https://gist.github.com/rdkcmf-jenkins/272d0c42a9f472af17e76bac1982e698'

[Copilot]

Pull request overview

Adds missing per-input audio level controls to the AudioMixer HAL AIDL surface (per dsAudio.h gap analysis), plus a new mixer-level fader property intended for main/associated balance (e.g., audio description).

Changes:

• Added setInputVolume() / getInputVolume() to IAudioMixerController for per-input volume (0–100).
• Added Property.FADER_LEVEL (0–100) to represent main vs associated balance.
• Updated hfp-audiomixer.yaml reference profile to declare FADER_LEVEL support for mixer resource id: 0.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
audiomixer/current/com/rdk/hal/audiomixer/IAudioMixerController.aidl	Adds per-input volume setter/getter methods with AIDL doc/comments.
audiomixer/current/com/rdk/hal/audiomixer/Property.aidl	Introduces new FADER_LEVEL mixer property with documentation.
audiomixer/current/hfp-audiomixer.yaml	Declares FADER_LEVEL in mixer 0 supported properties list.

[Copilot]

The doc says “Middleware must query capabilities before using this property”, but IAudioMixer.getCapabilities() returns Capabilities which currently doesn’t include any field that advertises supported mixer-level Property keys. This makes the guidance ambiguous/misleading for API consumers. Please clarify the wording (e.g., refer explicitly to the HFP supportedProperties list) or expose supported mixer properties via the AIDL capabilities so clients can actually query them at runtime.

Suggested change

	* in the HAL Feature Profile (hfp-audiomixer.yaml). Middleware must
	* query capabilities before using this property.
	* in the HAL Feature Profile (hfp-audiomixer.yaml), for example via the
	* HFP supportedProperties list. Middleware must verify that this property
	* is declared there before using it, as mixer property support is not
	* currently advertised through the AIDL Capabilities object.

[Copilot]

New documentation adds an @details tag. Per the project’s AIDL/Doxygen conventions, @details should be avoided (detailed text should follow @brief without a tag). Please remove @details here and keep the detailed description as plain comment text under @brief.

[Copilot]

For boolean-returning methods, other comments in this file use @returns + @retval entries to document each outcome (e.g., setInputRouting). Consider switching this block to that pattern so the success/failure semantics are unambiguous and consistent.

Suggested change

	* @returns true if the volume was set, false if the input index is invalid.
	* @returns Success status.
	* @retval true The volume was successfully set for the specified input.
	* @retval false The input index is invalid.

[rdkcmf-jenkins]

b'## WARNING: A Copyright scan failure has been waived

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• Commit: 39de011
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