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Feature #3400

closed

mobile: implement GAPK based audio capture / playback (via ALSA)

Added by fixeria over 5 years ago. Updated over 1 year ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
OsmocomBB mobile (host)
Start date:
07/17/2018
Due date:
% Done:

100%

Resolution:
Spec Reference:

Description

There is an initial implementation of GAPK based audio back-end in fixeria/audio.

The current implementation is limited, so TODO/FIXME:

  • init both I/O processing chains when CHANNEL MODE MODIFY is received,
  • deinit both I/O chains when a call is finished,
  • take care about PHY specific frame formats (e.g. TI),
  • optimize the application loop in order to improve performance,
  • support other than GSM FR codecs (currently FR is hardcoded),
  • compose codec support in Classmark depending on PHY capabilities and GAPK codec support.

Some points require a possibility to know the PHY features, such as:

  • TCH frame forwarding capability,
  • preferred TCH frame format,
  • full rate / half rate channel support,
  • AMR codec over FR / HR channel support.

Checklist

  • Init both I/O processing chains when CHANNEL MODE MODIFY is received
  • Support other than GSM FR codecs (currently FR is hardcoded)
  • Deinit both I/O chains when a call is finished
  • Take care about PHY specific frame formats (e.g. TI)
  • Optimize the application loop in order to improve performance
  • Investigate the problem with unpleasant audio effects
  • Get patches from fixeria/audio merged to master
  • libosmo-gapk should be optional dependency

Related issues

Related to OsmocomBB - Feature #4422: implement audio loop-back in mobileResolvedneels02/27/2020

Actions
Related to OsmocomBB - Feature #5812: mobile: missing AMR supportNew12/06/2022

Actions
Related to OsmocomBB - Feature #5815: mobile: compose Bearer Capability IE depending on PHY capabilities and GAPK codec supportNew12/06/2022

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