Summary of 3GPP Technical Document S4-260176

Document Information

• CR Number: 0013
• Specification: TS 26.117 v18.4.0
• Category: F (Correction)
• Release: Rel-18
• Work Item: IVAS_Codec

Purpose and Rationale

This Change Request addresses the incomplete referencing of IVAS codec levels defined in TS 26.250. The document removes placeholder text stating "IVAS codec level setting is TBD" and replaces it with proper IVAS level-specific capabilities to prevent implementer confusion regarding required encoder/decoder capabilities for given services.

Technical Contributions

1. Decoding Capabilities (Clause 5.2)

Additions:
- Introduced three distinct IVAS decoding capability levels:
- IVAS-L1: All decoding and rendering requirements for level 1 of the IVAS codec
- IVAS-L2: All decoding and rendering requirements for level 2 of the IVAS codec
- Both reference the complete suite of IVAS specifications (TS 26.250-26.258)

Clarifications:
- Maintained existing IVAS capability definition (all levels)
- Maintained IVAS-SR (split rendering) capability definition
- Retained note that IVAS decoder supports EVS decoding, meaning IVAS/IVAS-L1/IVAS-L2 capabilities imply EVS capability support

2. Encoding Capabilities (Clause 5.3)

Additions:
- Introduced two distinct IVAS encoding capability levels:
- IVAS-L1: All encoding requirements for level 1 of the IVAS codec
- IVAS-L2: All encoding requirements for level 2 of the IVAS codec
- Both reference TS 26.250, 26.252, 26.253, 26.251 (fixed-point), and 26.258 (floating-point)

Clarifications:
- Maintained existing IVAS encoding capability definition (all levels)
- Retained note that IVAS encoder supports EVS encoding, meaning IVAS capability implies EVS capability support

3. IVAS Operation Point - Bitstream Encoding Requirements (Clause 6.3.5.1)

Removals:
- Deleted placeholder note: "IVAS codec level setting is TBD"

No changes to:
- Input audio format requirements (mono, stereo, binaural, multi-channel, scene-based, MASA, object-based, OSBA, OMASA)
- Sampling frequency requirements (8 kHz, 16 kHz, 32 kHz, 48 kHz)
- Bitstream encoding specifications

4. IVAS Operation Point - Receiver Requirements (Clause 6.3.5.2)

Modifications:
- Updated to reference specific IVAS capability levels: "respective IVAS, IVAS-L1, IVAS-L2 or IVAS-SR media decoding capability"
- Added explicit reference to "supported IVAS codec level 1, 2 or 3 or the IVAS split rendering feature"

Removals:
- Deleted placeholder note: "IVAS codec level setting is TBD"

Retained:
- Note regarding EVS decoding support implication

5. IVAS Operation Point - Sender Requirements (Clause 6.3.5.3)

Modifications:
- Updated to reference specific encoding capabilities: "respective IVAS, IVAS-L1 or IVAS-L2-Enc media encoding capability"
- Added explicit reference to "supported IVAS codec level 1, 2 or 3"

Removals:
- Deleted placeholder note: "IVAS codec level setting is TBD"

No changes to:
- Audio format support requirements
- Sampling frequency requirements

6. Content Generation Requirements (Clause 7.5.2.5)

Modifications:
- Updated first bullet to reference all three encoding capabilities: "IVAS, IVAS-L1 or IVS-L2"
- Updated second bullet to reference all three sender requirements: "IVAS, IVAS-L1 or IVAS-L2"

No changes to:
- CMAF Track generation requirements
- CMAF Media Profile 'civs' conformance
- ABR distribution and CMAF Switching Set requirements

Impact

This CR provides clarity on IVAS codec level capabilities, enabling proper implementation guidance for:
- Decoder implementations supporting different IVAS levels
- Encoder implementations supporting different IVAS levels
- Service providers selecting appropriate codec levels for their use cases
- Interoperability between different IVAS capability levels