MP4RA specification reference

SAV1 ; Static Acoustic Verified X

SAVX is the specification family name. SAV1 is the MP4 brand code for the first SAVX profile. The profile identifies an ISOBMFF file containing static-to-eye visual content and a timed parametric acoustic verification track.

This page is a technical specification reference for MP4RA codepoint registration. It intentionally lists the identifiers and required ISOBMFF behavior first.

1. Registered identifiers

Identifier

Registry type

Description

SAV1

Brand

ISOBMFF brand for Static Acoustic Verified X version 1 profile.

savp

Sample entry

Parametric acoustic verification sample entry.

savC

Box

SAVX configuration box for the parametric acoustic verification track.

vatt

Track reference type

Viewport-attested track reference linking the verification track to the visual track.

2. Purpose

A SAV1 file carries static-to-eye visual content and timed acoustic verification metadata in the same ISOBMFF container. A SAVX-aware player may synthesize the verification signal and bind it to the rendered viewport using a cryptographic viewport commitment.

3. File structure

The ftyp box contains SAV1 as the major brand or a compatible brand.
The file contains a visual presentation track for the static-to-eye visual content.
The file contains a timed verification track using sample entry savp.
The savp sample entry contains or references a savC configuration box.
The verification track references the visual track using vatt, or an equivalent track reference until vatt registration is complete.

ftyp
  major_brand: SAV1
  compatible_brands: isom, iso6, SAV1

moov
  trak ; visual presentation track
  trak ; timed verification track
    stsd
      savp
        savC
  tref
    vatt ; verification track references the visual track

mdat
  visual samples and verification samples

4. Visual track

The visual track represents content that is static-to-eye for the intended presentation duration. A baseline implementation may use an intra-coded raster still or a 1 fps all-intra video track. Other static visual or deterministic layout representations are permitted by the SAVX specification.

5. Verification track

The savp track carries timed parametric acoustic verification data. The verification data is configured by savC and is intended to be synthesized by a compliant player as an acoustic verification signal. The acoustic profile may be ultrasonic, psychoacoustically masked audible, or another profile defined by the implementation.

6. savC configuration

The savC box defines immutable renderer and framing parameters, including:

synthesis sample rate;
slot, macro-frame, and super-frame duration;
lane plan and center frequencies;
atom types and envelope definitions;
maximum atoms per slot;
viewport commitment size;
forward error correction scheme.

7. Viewport attestation

The vatt track reference associates the verification track with the visual track. For each timed window, a compliant player may compute a cryptographic commitment of the rendered viewport and associate that commitment with the corresponding verification samples.

8. Receipts and privacy

A compliant application may emit signed receipts containing verification metadata such as viewport commitment, timing, verification metrics, and device attestation. The receipt model does not require transmission of the underlying visual content or consumer audio/video.

9. Compatibility

Legacy ISOBMFF readers that do not understand savp, savC, or vatt may ignore those identifiers and still process supported visual tracks. SAVX-aware readers use the verification identifiers to synthesize and verify the acoustic authentication layer.