--- license: cc-by-4.0 pretty_name: "PACC-T: Parallel Acoustic Confound Corpus, Telecoms" language: - en size_categories: - 100K/`), identical in PACC-T and PACC-P | | `pacc-t_.tar` | one condition: `pacc-t///.flac`, `params.csv`, `README.txt` | | `pacc-t_sample.tar` | 14 fixed sources (5 VCTK utterances on both mics, 4 AMI clips) through every condition | All audio is 16-bit mono FLAC. Extracting any set of tarballs builds one tree. `SHA256SUMS` and `TARBALL_INDEX.csv` list every tarball; `pacc-t_manifest.csv` lists every file with its sha256. Tarballs are deterministic: the same inputs rebuild byte-identical files. ## Per-clip records and verification Each condition's `params.csv` has one row per clip: input file and sha256, output sha256, sample rate, frame count, and the full command sequence, with paths as placeholders. - **Logged** (6 conditions: the EVS DTX-fixed conditions and their tandems): written at encode time, including the EVS encoder's own DTX status line. - **Recovered** (45 conditions, encoded before per-clip logging existed): each recorded command was re-executed on 60 clips per condition (20 per pool) and reproduced the stored audio bit for bit, 2,700 of 2,700. Rows were then filled from the files. The column `params_origin` says which applies. Before packaging, contract tests confirmed: every condition holds exactly the 5,992 base sources once each; no excluded source ships; manifest, params and file hashes agree. ## Tools and versions - ffmpeg 8.1 (full_build, www.gyan.dev, Windows static), with libopencore-amrnb, libvo-amrwbenc, libgsm, libilbc, libspeex, libopus, libmp3lame (LAME 3.100), liblc3 and libcodec2. The static build does not expose the other libraries' version strings. - EVS: 3GPP TS 26.443 floating-point reference C code, banner "Version 12.7.0 / 13.3.0", mirror github.com/wanglihe/3gpp-evs at commit 519236cc07ca209cb3aa2cc32de6ca686269839b. - Decoders: only `ilbc` pins its decoder (`-c:a libilbc`); all others use ffmpeg's default decoder for the stream, as recorded in the params. A start-burst scan of every file (first 40 ms peak against the rest of the clip) flagged none. ## Known edge cases See `EDGE_CASES.txt`. In short: EVS DTX variants coincide on clips without pauses; LC3 passes two very quiet clips through unchanged; `codec2_1300` runs at 1300 bps despite a 700 bps argument; 350 AMI sources carry clipping from the original recordings. ## Motivation The design of this corpus was motivated by Delgado et al. (ICASSP 2026), who argue that deepfake detection must account for how audio is presented through real communication channels, and by Lee et al. (ICASSP 2026), whose noise-aware multi-LoRA framework highlights real-world conditions. Neither group was involved in producing this dataset. - H. Delgado, G. Ramondetti, E. Dalmasso, G. Karvitsky, D. Colibro, H. Talib. "On Deepfake Voice Detection - It's All in the Presentation." ICASSP 2026. arXiv:2509.26471. - W. Lee, H. Dinh-Xuan, T.-P. Doan, S. Jung. "Dynamic Noise-Aware Multi LoRA Framework Towards Real-World Audio Deepfake Detection." ICASSP 2026. ## Licence and credits PACC-T is released under **CC BY 4.0** by Christopher Kleingertner (Moonscape Software). It is derived from: - **CSTR VCTK Corpus 0.92.** J. Yamagishi, C. Veaux, K. MacDonald. University of Edinburgh, CSTR, 2019. doi:10.7488/ds/2645. CC BY 4.0. - **AMI Meeting Corpus.** University of Edinburgh et al. https://groups.inf.ed.ac.uk/ami/corpus/. CC BY 4.0. J. Carletta (2006), "Announcing the AMI Meeting Corpus", ELRA Newsletter 11(1). Please credit these sources alongside PACC-T. ## Citation ```bibtex @dataset{moonscape_pacc_t_2026, author = {Kleingertner, Christopher and {Moonscape Software}}, title = {{PACC-T: Parallel Acoustic Confound Corpus, Telecoms}}, year = {2026}, version = {1.0}, publisher = {Zenodo}, doi = {10.5281/zenodo.23026393} } ```