| --- |
| pretty_name: Lambda Audio Corpus |
| annotations_creators: |
| - machine-generated |
| language_creators: |
| - found |
| language: |
| - ja |
| multilinguality: |
| - monolingual |
| source_datasets: |
| - KeisukeMiyamoto/nhk-archive-audio-30s |
| - KeisukeMiyamoto/nhk-radio-news-audio-30s |
| - reazon-research/reazonspeech |
| - KeisukeMiyamoto/tech-podcast-audio-30s |
| task_categories: |
| - automatic-speech-recognition |
| tags: |
| - audio |
| - speech |
| - japanese |
| - asr |
| - broadcast |
| - news |
| - podcast |
| - reazonspeech |
| - flac |
| size_categories: |
| - 1M<n<10M |
| license: other |
| dataset_info: |
| - config_name: default |
| features: |
| - name: id |
| dtype: string |
| - name: audio |
| dtype: |
| audio: |
| sampling_rate: 16000 |
| - name: text |
| dtype: string |
| - name: raw_text |
| dtype: string |
| - name: speech_segments |
| list: |
| - name: start |
| dtype: float64 |
| - name: end |
| dtype: float64 |
| - name: has_speech |
| dtype: bool |
| - name: duration |
| dtype: float64 |
| - name: prev_id |
| dtype: string |
| - name: prev_text |
| dtype: string |
| - name: origin |
| dtype: string |
| splits: |
| - name: train |
| num_examples: 2330321 |
| - name: test |
| num_examples: 11776 |
| - name: validation |
| num_examples: 11776 |
| configs: |
| - config_name: default |
| data_files: |
| - split: train |
| path: train/*.parquet |
| - split: test |
| path: test/*.parquet |
| - split: validation |
| path: validation/*.parquet |
| --- |
| |
| # Lambda Audio Corpus |
|
|
| This is a combined Japanese automatic speech recognition corpus containing 2,353,873 clips (8,592.83 hours). It combines archive, podcast, and ReazonSpeech data in a common schema. Audio is embedded as 16 kHz mono FLAC, and stored durations range from 0.46 to 30 seconds. |
|
|
| ## Sources |
|
|
| | `origin` | Included clips | Duration | Source | |
| | --- | ---: | ---: | --- | |
| | `nhk-archive-audio-30s` | 137,106 | 1,067.26 hours | [NHK Archives Audio 30s](https://huggingface.co/datasets/KeisukeMiyamoto/nhk-archive-audio-30s) | |
| | `reazon-speech-v2` | 1,023,030 | 1,821.55 hours | [ReazonSpeech v2](https://huggingface.co/datasets/reazon-research/reazonspeech) | |
| | `tech-podcast-audio-30s` | 1,127,635 | 5,509.03 hours | [Tech Podcast Audio 30s](https://huggingface.co/datasets/KeisukeMiyamoto/tech-podcast-audio-30s) | |
|
|
| The table describes the records included here and does not imply that every upstream dataset is included in full. |
|
|
| ## Splits |
|
|
| | Split | Clips | Duration | Ratio by rows | |
| | --- | ---: | ---: | ---: | |
| | train | 2,330,321 | 8,506.72 hours | 99.00% | |
| | test | 11,776 | 43.35 hours | 0.50% | |
| | validation | 11,776 | 42.76 hours | 0.50% | |
|
|
| Complete Parquet files were assigned to splits to approximate the target row ratios. The input rows were shuffled with seed 42 before files were assigned. The splits are not speaker-, program-, episode-, or source-disjoint. |
|
|
| ## Columns |
|
|
| | Column | Description | |
| | --- | --- | |
| | `id` | Unique segment ID. | |
| | `audio` | Embedded 16 kHz mono FLAC audio. | |
| | `text` | Transcript used as the ASR target. Its provenance and correction process depend on `origin`. | |
| | `raw_text` | Transcript before correction, when supplied by the source dataset. It is null for `reazon-speech-v2`. | |
| | `speech_segments` | Speech intervals in seconds relative to the stored clip. | |
| | `has_speech` | Whether speech is present; true for all included records. | |
| | `duration` | Stored clip duration in seconds. | |
| | `prev_id` | Previous related segment ID, when available. | |
| | `prev_text` | Transcript of the previous related segment, when available. | |
| | `origin` | Source dataset identifier shown in the Sources table. | |
|
|
| For the NHK and podcast sources, `raw_text` was generated with Whisper large-v3-turbo and `text` contains LLM-assisted corrections. For `reazon-speech-v2`, `text` is derived from the supplied ReazonSpeech transcription and `raw_text` is unavailable. A record referenced by `prev_id` may be in another split or may have been removed during filtering or deduplication; `prev_text` can therefore cause contextual leakage. |
|
|
| ## Usage |
|
|
| ```python |
| from datasets import load_dataset |
| |
| dataset = load_dataset( |
| "KeisukeMiyamoto/lambda-audio-courpus", |
| split="train", |
| streaming=True, |
| ) |
| |
| record = next(iter(dataset)) |
| print(record["id"], record["origin"], record["duration"], record["text"]) |
| ``` |
|
|
| Streaming is recommended because the Parquet files occupy approximately 575.0 GiB. |
|
|
| ## Source Terms and License |
|
|
| This combined dataset uses `license: other` because rights and conditions differ by source. Copyright in the original recordings remains with the respective creators and rights holders. |
|
|
| - NHK-derived data remains subject to the applicable NHK terms, including the [NHK Creative Library usage rules](https://www.nhk.or.jp/archives/creative/rule.html). |
| - ReazonSpeech is distributed under CDLA-Sharing-1.0 and its dataset card additionally restricts use to the purpose permitted by Article 30-4 of the Japanese Copyright Act. Review and accept the [ReazonSpeech terms](https://huggingface.co/datasets/reazon-research/reazonspeech) before use. |
| - Podcast recordings remain the property of their creators and publishers; users must verify that their intended use is permitted. |
|
|
| Users are responsible for reviewing every upstream dataset card and ensuring compliance with all applicable licenses, terms, copyright restrictions, privacy requirements, and laws. |
|
|
