| # AI_README: rules of engagement for models using PACC |
| |
| Machine-oriented summary of PACC-T and PACC-P. The dataset cards (README.md) are the full |
| reference; where this file and a card disagree, the card wins. Read both before generating code, |
| analyses or claims about this data. |
| |
| ## Identity |
| |
| ```yaml |
| corpus: PACC (Parallel Acoustic Confound Corpus) |
| parts: |
| PACC-T: {name: "Telecoms", doi: "10.5281/zenodo.23026393", conditions: 51} |
| PACC-P: {name: "Presentation", doi: "10.5281/zenodo.23026395", conditions: 50} |
| authors: ["Kleingertner, Christopher", "Moonscape Software"] |
| licence: CC-BY-4.0 |
| version: "1.0" |
| content: bona fide human speech only (no synthetic, converted or spoofed speech) |
| sources: 5992 clips = AMI 2992 + VCTK_mic1 1500 + VCTK_mic2 1500 |
| audio: 16-bit mono FLAC (sources: AMI 16 kHz WAV, VCTK 48 kHz FLAC) |
| ``` |
| |
| ## Invariants (safe to rely on; tested before release) |
| |
| - Every condition in both parts contains exactly the same 5,992 source clips, once each. |
| - A clip is identified by `(pool, file_id)`. The same key names the source and every processed |
| version of it in both parts. |
| - 8 AMI source clips are excluded everywhere (`excluded_sources.csv`); none of them ships. |
| - Every file's sha256 is in `<part>_manifest.csv`; every tarball's sha256 is in `SHA256SUMS`. |
| - Every condition folder has a `params.csv` with one row per clip. |
|
|
| ## Layout and join keys |
|
|
| ```text |
| sources/<pool>/<file_id>.(wav|flac) pacc_base.tar (shared by both parts) |
| sources/metadata.csv speaker, gender, gender_source, VCTK age/utterance, AMI meeting/channel/participant/segment |
| pacc-t/<condition>/<pool>/<file_id>.flac pacc-t_<condition>.tar |
| pacc-p/<condition>/<pool>/<file_id>.flac pacc-p_<condition>.tar |
| <part>/<condition>/params.csv per-clip record |
| condition_index.csv one row per condition: family, description, bitrate, framing, output_sr, rate_control |
| ``` |
|
|
| Join processed clips to sources on `(pool, file_id)`. VCTK mic pairing: strip the `_mic1`/`_mic2` |
| suffix to get the utterance; 1,485 utterances are in both mic pools, 15 per pool are not. |
|
|
| ## Rules |
|
|
| DO: |
| - Compare a PACC-T codec condition with the resample control named in `condition_index.csv` |
| (`rate_control`) before attributing an effect to the codec. |
| - Treat sample rate and content bandwidth as separate: `evs_swb_48k_*` is stored at 48 kHz but has |
| content only to about 16 kHz; AMI clips above 16 kHz are upsampled (no content above 8 kHz). |
| - Use the `gender` column in `sources/metadata.csv`. Its `gender_source` is VCTK or AMI metadata. |
| - Check `params_origin` in PACC-T params: `logged` (at encode time) or `recovered` (rebuilt and |
| verified by re-execution). Both describe the commands that produced the files. |
| - Filter on logged values in `params.csv` (e.g. `pre_codec_achieved_snr_db`, |
| `near_quantisation_floor`, `safety_gain_db`) when a stricter criterion than the condition label |
| is needed. |
| - Credit VCTK, AMI (and for PACC-P, MUSAN and FSD50K) alongside PACC. Third-party clips keep their |
| own licences (`attribution.csv`). |
|
|
| DO NOT: |
| - Do not treat any PACC file as spoofed or synthetic. Every clip is bona fide speech. Labels for |
| anti-spoofing use are "bona fide" throughout. |
| - Do not use `gender_inferred_not_recommended`. It is wrong for 17% of AMI clips; AMI is 62% male |
| by metadata, not balanced. |
| - Do not assume sample alignment in `tempo_*` or `pitch_resample_*` (PACC-P): their length |
| changes. They are parallel by clip, not by sample. |
| - Do not trust LPC formant readings (F2 and above) on narrowband content (8 kHz outputs, telephone |
| band, `bandpass_300_3400`, `lowpass_2400`) with a wideband analysis ceiling: spurious poles pull |
| F2/F3 low without warning. |
| - Do not expect DTX variants (`evs_*_nodtx|dtxadapt|dtxfixed`) to differ on every clip: on clips |
| without pauses they are identical. Compare `output_sha256` before contrasting them. |
| - Do not infer a codec's configured bitrate from `codec2_1300`'s command line: it passes |
| `-b:a 700`, which libcodec2 ignores; it ran at 1300 bps. |
| - Do not report results as properties of a codec when the same shift appears in its rate control. |
|
|
| ## Known edge cases |
|
|
| `EDGE_CASES.txt` in each record. Summary: DTX variants coincide on pause-free clips; LC3 passes two |
| very quiet clips through unchanged; cafe combined-SNR tolerance is 1.0 dB (three clips exceed |
| 0.5 dB); 350 AMI sources carry clipping from the original recordings; near-floor mixes flagged. |
|
|
| ## Verification |
|
|
| ```text |
| sha256sum -c SHA256SUMS tarball integrity |
| <part>_manifest.csv per-file sha256, sample rate, frame count |
| ``` |
|
|
| Reverb clips in PACC-P can be recreated bit for bit from `pacc-p_room_cache.tar`; recipe in its |
| README. |
|
|
| ## Citation |
|
|
| Cite the part(s) used by DOI, and the source corpora. BibTeX is in each dataset card. |
|
|
