open-standards/wai/live-conformance/audio-mark/README.md

live-conformance/audio-mark — the audio watermark scheme wai-mark:band64

The corpus of the registered audio scheme of the second marking layer, extensions/synthesis.md §7.10, of its measurement (§7.10.7), and of its robustness records (extensions/robustness-evidence.md §10).

Provenance. Every signal here is generated: wai_audio_mark_vectors gen writes the voice and the music from fixed seeds (audio_mark::voice, a source-filter model, and audio_mark::music, a few synthesised instruments), integer throughout. No recording is stored. The recorded speech the measured records name (robustness/measured/speech*.json) is the test-clean set of the LibriSpeech corpus of read English speech (Panayotov, Chen, Povey and Khudanpur, ICASSP 2015), licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), fetched from openslr.org/12 as test-clean.tar.gz with SHA-256 39fde525e59672dc6d1551919b1478f724438a95aa55f874b576be21967e6c23. It is named here only by the SHA-256 of each item's samples, read as 16 kHz mono and cut to its first 20 s (or 10 s); its samples are not in this repository.

Files

• scheme-band64.json: the scheme's definition, the bytes whose SHA-256 is the scheme's digest (§7.10.1).
• audio/<SHA-256>.pcm: the unmarked audio the vectors name, raw S16LE, channels interleaved, each file named by the SHA-256 of its bytes: a voice of 7 s at 8 kHz, one channel, and music of 6 s at 12 kHz, two channels.
• vectors.json:
  • scheme: the term, the digest, the cosine tables' digest, the shuffle's first and last 16 entries, the first 16 signs, the mask, and the false-positive bound of §7.10.6;
  • lg and shift: values of the integer logarithm and of the gain's shift S(a) (§7.10.2, §7.10.4);
  • embeds: each stored audio (audio), its rate and channels, a payload, the marked samples' digest (marked), the cells that carried a bit, and each cell's last gain (two bytes each, big-endian, in cell order);
  • detects: each audio a source names, its size and digest, and what the detector reads: the payload, the offset, the phase and the errors corrected, or null;
  • battery_sample: every pinned attack of §7.10.7 applied to the stored voice, marked and unmarked, at the attack's seed, with the result's digest and what the detector reads;
  • cases: cases of §11.1. Their decoded and unmarked samples are each named by a source: stored audio (audio, with its rate and channels), optionally marked under a payload (marked), then optionally transformed (derive: a transform of robustness-evidence §4.1, its parameters and seed), then optionally with one sample's lowest bit flipped (flip). Each case states what a verifier gives it, as live-conformance/synthesis/ states its vectors'.
• battery-band64.json: the measurement of §7.10.7's pinned attacks over the generated sets, voice (16 voices of 20 s at 16 kHz, one channel) and music (8 pieces of 15 s at 24 kHz, two channels). It holds each item's SNR and segmental SNR, each attack's tallies per set, the unmarked items' readings, the statistics of the words the detector reads from unmarked items (§7.10.6), the bound, and the attacks every item survived.
• robustness/: the scheme's robustness records (robustness-evidence §10).
  • corpus/: the corpus documents.
  • records/: the conformance record over the two stored sounds, reproduced end to end; the records over the generated sets; and their claim.
  • measured/: the records of the whole battery, its measured transforms among it, over the generated voices and over the recorded speech, with their claim, the measurements they come from, the recorded speech's corpus documents, and the unmarked detections over the whole recorded set and over generated music (negatives*.json).

The encoder of the measured transforms

The measured records (robustness-evidence §4.2) were run on an arm64 host by wai_audio_mark_vectors measure and measure-dir, through FFmpeg 9.0.2 with libopus 1.6.1 (wai-attack:opus, application voip), LAME 4.0 (wai-attack:mp3), and FFmpeg's own AAC, G.722, G.726 and G.723.1 encoders. Each codec's result depends on its encoder's build, so the records are stated. The same command on the same builds writes the same bytes.

Running

cd ../../wai-rs
cargo run --release --no-default-features --features robustness --bin wai_audio_mark_vectors -- verify ../live-conformance/audio-mark
cargo run --release --no-default-features --features robustness --bin wai_audio_mark_vectors -- gen ../live-conformance/audio-mark   # regenerate
cd ..
python3 -I live-conformance/audio_mark_verify.py live-conformance/audio-mark

Re-measuring needs an FFmpeg-compatible encoder: wai_audio_mark_vectors measure <corpus-dir> <ffmpeg>, and for a directory of recordings measure-dir <corpus-dir> <ffmpeg> <name> <audio-dir> <seconds> <count>.

Pass is byte equality, and every case reaching the outcome it states. A difference is a conformance failure of the file or the implementation. Report it as a failure, never as close enough.