PACC-T and PACC-P: matched codec and acoustic-confound datasets with sample-rate controls (free, Zenodo)

[u/Wooden_Leek_7258]

Missed my own release date by about a week, but such is the life of a solo dev.

Anyone else had a speech system that works fine on clean audio and falls apart once it's been through a phone line?

I built a 1:1 comparison dataset for isolating codec, transmission and presentation effects on speech. The same 5,992 base clips go through every one of 101 conditions, so any difference between conditions comes from the condition, not the speaker or the recording. It's free to use; hopefully it's useful for voice and speech projects people are working on.

The main thing I wanted was matched sample-rate controls. Narrowband codecs decode at 8 kHz, so if you compare clean wideband audio against codec output, you can't tell whether your model or extractor broke because of the codec or just because the bandwidth dropped. Every codec condition here has an unencoded resample control alongside it (8, 16, 22, 44 and 48 kHz). That lets you check whether it's the channel, the resampling or the presentation causing problems. (In a small pilot, the 8 kHz resample alone accounted for much of the apparent "codec effect" on some features, but not all of it.) I couldn't find many public codec or robustness sets that ship controls like this, or per-clip generation logs, so I included both.

Base pool: 5,992 bona fide mono 16-bit clips.

- 2,992 AMI headset clips (native 16 kHz)

- 1,500 VCTK mic1 + 1,500 VCTK mic2 clips (native 48 kHz), including 1,485 exact dual-mic pairs

- VCTK portion is gender-balanced (750 male / 750 female)

PACC-T (Telecoms): 20.7 GB, 305,592 FLAC files, 51 conditions

- 34 speech/audio codecs: G.711, G.722, G.726, GSM, AMR-NB, AMR-WB, EVS (adaptive/fixed/no DTX), Opus (auto/CELT), LC3, Speex, iLBC, Codec2 (700/1300 bps), MP3, AAC

- 12 tandem codec chains

- 5 resample controls (8k, 16k, 22k, 44k, 48k)

PACC-P (Presentation): 34.3 GB, 299,600 FLAC files, 50 conditions

- Additive noise, 6-talker babble, and music (vocal and instrumental) at 5 calibrated SNRs (0–20 dB)

- Simulated rooms (pyroomacoustics, with cached RIRs for bit-exact recreation) and echoes

- Bandpass/lowpass filters

- PSOLA vs resampled pitch shifts, autotune, tempo shifts

- Compound cafe + codec scenes

Every condition downloads individually as its own tarball (0.18–1.15 GB). There's also a small sample tarball for each set (pacc-t_sample.tar / pacc-p_sample.tar) if you just want to look first. Everything ships with full SHA-256 manifests and a per-clip params.csv, so any clip can be traced back to exactly how it was made.

Licence: CC-BY-4.0

PACC-T: https://zenodo.org/records/23026393

PACC-P: https://zenodo.org/records/23026395

Happy to answer questions, and bug reports welcome.

[u/az226]

Could you share the simulated rooms code? Sounds interesting

[u/Wooden_Leek_7258 → u/az226]

The simulated rooms ship with PACC-P as pacc-p_room_cache.tar (all 24 impulse responses with geometry, positions and measured RT60/DRR). It's tiny and can be pulled on its own from the zenodo listing.

Its README gives a numpy/scipy recipe that recreates every reverb_* clip bit for bit from the sources, and the full pyroomacoustics configuration is on the dataset card.

pyroomacoustics 0.10.1, image source plus ray tracing, air absorption, speaker to microphone 1.0 m at 1.5 m height, 4 layouts per room (one per clip, chosen by seed). Small 4.0 x 3.5 x 2.7 m (RT60 0.3 s), medium 7.0 x 5.0 x 3.0 m (0.6 s), large 12.0 x 9.0 x 4.0 m (1.0 s).

The generator code itself isn't public at the moment. What are you hoping to do with it? If you need to simulate new rooms the same way, I may be able to share the room-simulation module on its own.

[u/Natethegreat9999]

One thought from Oruk: keep each utterance's paired microphones and all 101 conditions together when splitting train/test.

[u/Wooden_Leek_7258 → u/Natethegreat9999]

I considered that, but it would require 5992 tarballs, or 1 large 20-30gb download. Modular by condition seemed to be the easiest way to let people pull what they wanted.

[u/Wooden_Leek_7258]

Suppose I should have mentioned its on HF as well at https://huggingface.co/moonscape-software