Report from Audio SWG Teleconference on DaCAS (9 December 2025)

Meeting Overview

The Audio SWG held a teleconference on DaCAS (Diverse audio CApturing system for Smartphone devices) with 19 participants for 1 hour. Three input documents were discussed, all focused on defining the evaluation approach, specification methodology, and deliverables for DaCAS example solutions.

Main Technical Contributions

S4aA250140: Evaluation Approach for DaCAS Example Solutions (Nokia, Fraunhofer IIS)

Key Proposals:
- Self-evaluation approach for example solutions rather than cross-evaluation
- High-level documentation guidelines for proponents
- Informal assessment against requirements in TS 26.261
- Updated work plan with two timeline options depending on evaluation procedure chosen

Timeline Proposals:
- Table 1: Faster timeline with self-evaluation only
- Table 2: Extended timeline including cross-evaluation
- Key milestones: submission of example solutions in Montreal, specification work following

Discussion Points:
- Mixed support: some agreement on self-evaluation concept, but reservations about completely skipping cross-evaluation
- Questions on deliverable package definition (executable vs source code)
- Concerns about timeline dependencies on deliverable agreements
- Clarification needed on what "informal evaluation" means in practice
- Need to distinguish between demonstrating feasibility vs determining suitability of solutions

Outcome: Document noted; offline discussions encouraged to provide potential revision

S4aA250141: Specification of Suitable DaCAS Example Solutions (Nokia)

Key Proposals:
- Two-tier approach for example solutions:
- All evaluations and documentation included in informative Annex of TS 26.533
- Example solutions additionally meeting requirements from TS 26.261 specified in TS 26.533 (status TBD)

Documentation Requirements:
- Algorithmic description with sufficient detail for implementation
- Optional elements:
- Adaptation considerations for commercial devices
- Support for IVAS PI (Parametric Information) data
- Integration with commercial processing pipelines
- Device limitations and generalization capabilities

Discussion Points:
- Questions on required detail level: pseudocode vs source code
- Clarification that last three bullets are optional/invitational
- Relationship to ATIAS Phase 3 work
- Distinction between two categories:
1. Feasible example solutions (demonstration via self-evaluation)
2. Endorsed solutions meeting TS 26.261 requirements (requiring testing)
- Suggestion to share draft updates via SA4 reflector for broader input

Outcome: Document noted; revision expected with broader consultation

S4aA250142: Example Solution Deliverables (Bytedance, Xiaomi)

Key Proposals for Deliverable Package:

For Neural Network-based Solutions:
- Code package including:
- Training code
- Inference code
- Model checkpoints
- Rationale: enable retraining for different devices beyond target device

For DSP-based Solutions:
- Algorithmic description allowing reimplementation

General Requirements:
- Legal framework submission (depending on solution specifics)
- Sufficient details to convert raw microphone recordings to IVAS formats

Discussion Points:
- Strong concerns about mandating training code and checkpoints:
- Risk of providing false impression of quality transferability
- Training typically tailored to specific devices
- Cannot guarantee similar quality on different devices
- May be unnecessary if solution generalizes without retraining
- Distinction between providing model (equivalent to DSP description) vs full training pipeline
- Legal framework requirements too general and need clarification
- Fundamental difference in reproducibility between DSP descriptions (anyone can reimplement) and NN solutions

Outcome: Document noted; significant concerns raised about mandatory training code requirements

Cross-Cutting Issues and Open Questions

Evaluation Methodology

• Self-evaluation vs cross-evaluation trade-off: timeline efficiency vs validation robustness
• Need to define "informal assessment" against TS 26.261 requirements
• Distinction between feasibility demonstration and suitability determination

Deliverables Definition

• Critical dependency: timeline cannot be finalized without agreed deliverable package
• Balance between sufficient detail for reproducibility and practical constraints
• Different requirements for NN-based vs DSP-based solutions

Specification Approach

• Two-tier system emerging: informative documentation for all vs normative specification for qualified solutions
• No selection procedure planned, but potential endorsement mechanism discussed
• Relationship to requirements verification unclear

Timeline Dependencies

• Agreement on deliverables needed at SA4#135 (India, February 2026) to maintain schedule
• Submission of example solutions potentially at SA4#136 (Montreal)
• Specification work to follow based on submitted packages and evaluation reports

Next Steps

• Offline discussions encouraged on evaluation approach (S4aA250140)
• Revision expected for specification approach with broader consultation via reflector (S4aA250141)
• Further clarification needed on deliverable requirements, particularly for NN-based solutions (S4aA250142)
• Next DaCAS telco scheduled for January 13, 2026, 15:00-16:00 CET
• Repository discussion for material exchange (forge) to be continued offline