Audio and video content provenance

A signed C2PA manifest sits inside WAV, MP3, MP4, MOV and other audio and video files, in a part players skip. It shows who published the file and whether a frame or a sound changed since.

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In an MP4, MOV, HEIC or AVIF file, the label sits in its own box beside the boxes that hold the picture and sound. — ISO BMFF files keep the label in its own box.
BMFF
File container
Manifest store

Formats: 7 audio and 9 video formats.
Where it sits: In its own part of the file. Players skip it.
AI voice and video: The label can say the media was made with AI.
Live streams: Signed piece by piece as they air.

Where the label sits in each audio and video format

Each format is built from parts, and the label gets one of its own. That is a chunk in WAV and AVI, a tag frame in MP3, and a box in ISO BMFF files like MP4.

Where the signed label sits in 10 audio and video formats.
Format	Where the label sits	Made for
WAV	In its own chunk, next to the chunk that holds the sound	Music masters, Broadcast audio, Podcast masters
MP3	In the tag block at the start of the file, where the title and artist live	Podcasts, Music, Audio news
M4A	In its own box, one of the labelled parts the file is built from	Music stores, Podcast hosting, High-quality streaming
AAC	In its own box, one of the labelled parts the file is built from	Streaming, Phone audio, Broadcast
FLAC	In a tag block at the start of the file, as in an MP3	Lossless music, Audio archives, Hi-fi streaming
MPA	In the tag block at the start of the file, the same place as in an MP3	Broadcast audio, Older media systems
MP4	In its own box, one of the labelled parts the file is built from	Web video, Streaming, Social video
MOV	In its own box, one of the labelled parts the file is built from	Video production, Film and TV, Editing workflows
M4V	In its own box, one of the labelled parts the file is built from	Apple TV video, iTunes video, Apple device playback
AVI	In its own chunk, next to the chunks that hold the picture and sound	Video archives, Security footage, Industrial video

Prove the real footage instead of guessing at fakes

A deepfake detector guesses from patterns. Provenance answers a different question: did this footage come from this newsroom, and is it unchanged? If one frame changed, the check says so.

A signed text mark gives a yes or no anyone can check, valid or changed; a statistical pattern runs through a model and gives a probability, such as 72 percent likely AI. — A cryptographic mark gives a checkable answer. A statistical pattern gives a probability.
Cryptographic watermarking
Statistical watermarking
Digital signature

Provenance vs. detection

Live streams, signed as they air

A live stream is cut into short pieces. Each piece gets its own label, linked to the one before, so an edit shows where the chain breaks.

A live stream is cut into short pieces, each with its own label tied to the label before it; one swapped piece breaks the thread, so the check shows exactly where. — Each piece of a live stream carries a label linked to the one before. A swapped piece breaks the chain where it happens.
Live stream provenance
C2PA manifest
BMFF

How live signing works

For engineers

Show the technical detail

Embedding per container

RIFF (WAV, AVI): JUMBF manifest store in a C2PA chunk.
ID3 (MP3): JUMBF manifest store in an ID3v2 GEOB frame tagged with the C2PA media type.
ISO BMFF (MP4, MOV, M4V, M4A, AAC): JUMBF manifest store in a C2PA uuid box. Tools that do not know the box skip it.
FLAC: JUMBF manifest store in a leading ID3v2 GEOB frame, as in MP3. Legacy FLAC APPLICATION blocks are still read.

C2PA embedding location by audio and video format.
Format	MIME type	Embedding
WAV	audio/wav	JUMBF manifest store in a C2PA chunk of the RIFF container
MP3	audio/mpeg	JUMBF manifest store in an ID3v2 GEOB (general encapsulated object) frame
M4A	audio/mp4	JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure
AAC	audio/aac	JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure (AAC audio carried in an MP4 container)
FLAC	audio/flac	JUMBF manifest store in a leading ID3v2 GEOB frame (MIME application/c2pa); legacy FLAC APPLICATION blocks (app id c2pa) remain readable
MPA	audio/mpa	Read as MPEG audio (audio/mpa is an accepted alias of audio/mpeg): JUMBF manifest store in an ID3v2 GEOB frame
MP4	video/mp4	JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure
MOV	video/quicktime	JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure (QuickTime uuid atom)
M4V	video/x-m4v	JUMBF manifest store in a C2PA uuid box in the ISO BMFF structure
AVI	video/x-msvideo	JUMBF manifest store in a C2PA chunk of the RIFF container

POST /api/v1/sign/media also takes optional spread-spectrum audio and video watermarks (Enterprise), which carry an identifier that can lead back to the record if the manifest is stripped.

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