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---
license: cc-by-4.0
pretty_name: Lombard GRID Cross-Modal Utterance Retrieval
task_categories:
- any-to-any
tags:
- mteb
- moeb
- audio-video-retrieval
- cross-view-retrieval
- speech-retrieval
dataset_info:
- config_name: condition_pairs
  features:
  - name: plain_recording_id
    dtype: string
  - name: lombard_recording_id
    dtype: string
  splits:
  - name: test
    num_bytes: 23760
    num_examples: 540
  download_size: 13102
  dataset_size: 23760
- config_name: matching_utterances
  features:
  - name: audio_id
    dtype: string
  - name: front_video_id
    dtype: string
  - name: profile_video_id
    dtype: string
  splits:
  - name: test
    num_bytes: 36720
    num_examples: 540
  download_size: 19393
  dataset_size: 36720
- config_name: media
  features:
  - name: recording_id
    dtype: string
  - name: audio_id
    dtype: string
  - name: front_video_id
    dtype: string
  - name: profile_video_id
    dtype: string
  - name: front_video
    dtype: video
  - name: profile_video
    dtype: video
  - name: audio
    dtype: audio
  splits:
  - name: test
    num_bytes: 538091712
    num_examples: 1080
  download_size: 498569082
  dataset_size: 538091712
configs:
- config_name: condition_pairs
  data_files:
  - split: test
    path: condition_pairs/test-*
- config_name: matching_utterances
  data_files:
  - split: test
    path: matching_utterances/test-*
- config_name: media
  data_files:
  - split: test
    path: media/test-*
---

# Lombard GRID Cross-Modal Utterance Retrieval

Four MTEB/MOEB utterance-retrieval tasks derived from the
[Lombard GRID corpus](https://zenodo.org/records/3736465): audio-to-video, video-to-audio,
frontal-to-profile video, and plain-to-Lombard video+audio. Relevance always
requires the same utterance recording or the same speaker-and-sentence pair;
speaker identity alone is never relevant.

The source paper introduced the corpus but did not define these retrieval tasks.
Relevance is derived from native recording, speaker, sentence-code, condition,
and camera-view labels.

## Frozen evaluation protocol

- Speakers: 54 (`s2` through `s55`; `s1` was excluded by the source)
- Selected sentence codes: 540 (10 per speaker)
- Published media recordings: 1080
- Matching-task recordings: 540 (5 plain and 5 Lombard per speaker)
- Selection seed: `mteb-lombard-grid-retrieval-v2`

For every speaker, eligible sentence codes present in both conditions and all
three media streams are ordered by SHA-256 over the fixed seed, speaker, and
sentence code. The first ten valid pairs are retained. Five plain and five
Lombard recordings per speaker are then selected deterministically for the three
same-recording tasks. Opaque IDs are published; speaker, condition, sentence
code, transcription, and other text are not encodable dataset features.

| Task | Queries | Corpus | Qrels | Positives/query |
|---|---:|---:|---:|---:|
| Audio to frontal/profile video | 540 | 1,080 | 1,080 | 2 |
| Frontal/profile video to audio | 1,080 | 540 | 1,080 | 1 |
| Frontal video to profile video | 540 | 540 | 540 | 1 |
| Plain frontal video+audio to Lombard frontal video+audio | 540 | 540 | 540 | 1 |

## Source audit and release discrepancies

The official JSON archive contains 5,340 rows, while each
media archive contains 5,390 files. All three
media archives have exactly the same recording filenames. The media restore 50
`s31` recordings absent from JSON. `s51` has only 40 plain and 50 Lombard files,
rather than the advertised 50 of each. `s14` has 51 plain and 49 Lombard rows,
including a duplicate `prwr3a` recording key. The JSON metadata labels 69
recordings as `WRONG`. Media filenames mark 70: the additional one is among the
50 media-only `s31` recordings. All 70, plus the one legacy-named duplicate, are
excluded from selection. Four frontal MOV files lack a `moov` atom and are corrupt:
`s32_l_pwip9p`, `s32_p_bwwj2n`, `s33_l_pwajza`, and `s33_p_sgwq2s`.

The deterministic selection required 0 fallback(s). The selected
protocol remains exactly balanced after exclusions.

## Media processing and validation

The released MOV files are already H.264/yuv420p visual-only clips, so
2,160 selected videos are copied without
transcoding. 0 video(s) required a lossless video-stream remux to
remove embedded audio. Separate source WAV files are copied without transcoding.

All 1080 frontal videos,
1080 profile videos, and
1080 audio files were decoded
completely with TorchCodec during construction. Matching source filename stems
establish audiovisual correspondence. Selected video/audio duration differences
were checked and paired decoding succeeded. The source paper reports
correlation-based audiovisual alignment before utterance extraction; this
construction did **not** independently verify signal-level synchronization.

The shared configs avoid storing the same media repeatedly across four tasks:

- `media/test`: opaque recording and modality IDs, frontal video, profile video, audio
- `matching_utterances/test`: opaque audio, frontal-video, and profile-video IDs
- `condition_pairs/test`: opaque plain- and Lombard-recording IDs

The MTEB task loaders project these configs into the standard query, corpus, and
qrel structures without exposing source labels to embedding models.

## Evaluation

The primary metric for all four tasks is nDCG@10. Other standard MTEB retrieval
metrics are reported as secondary results. These protocols are newly derived, so
there is no source-paper retrieval score to reproduce.

## License and attribution

The source corpus is released under the
[Creative Commons Attribution 4.0 International license](https://creativecommons.org/licenses/by/4.0/).
Please attribute the original authors and cite the paper below. The MTEB task
metadata and this card both use `cc-by-4.0`.

## Responsible use

The source contains identifiable faces and voices. Although these tasks evaluate
utterance correspondence rather than biometric identification, the representations
may still encode identity and demographic attributes. Users should consider
participant consent, privacy, applicable biometric-data law, subgroup behavior,
and downstream misuse before training or deploying related systems.

## Citation

```bibtex
@article{alghamdi2018corpus,
  author = {Alghamdi, Najwa and Maddock, Steve and Marxer, Ricard and Barker, Jon and Brown, Guy J.},
  title = {A corpus of audio-visual Lombard speech with frontal and profile views},
  journal = {The Journal of the Acoustical Society of America},
  volume = {143},
  number = {6},
  pages = {EL523--EL529},
  year = {2018},
  doi = {10.1121/1.5042758},
}
```