What Makes Olewave's Speech Data Cleaning Pipeline Effective and Unique

Research

What Makes Olewave's Speech Data Cleaning Pipeline Effective and Unique

How Olewave's Olign pipeline turns raw audio into production-ready ASR/TTS training data with validated transcripts, word-level timestamps and confidence scores, without human labelers.

What Makes Olewave's Speech Data Cleaning Pipeline Effective and Unique

Olewave's state-of-the-art and highly customizable speech data cleaning pipeline seamlessly integrates with its speech data collection pipeline, together forming the Olewave's speech data curation pipeline. This end-to-end system is meticulously designed to deliver high-quality, consistent, and cost-effective speech datasets at scale, tailored for a wide range of downstream applications. Additionally, we are offering large-scale, cost-effective speech datasets curated through our pipeline, available in multiple languages and covering diverse topics.

The figure below illustrates the streamlined workflow of our speech data cleaning pipeline, showcasing its ability to transform raw, unstructured speech data into polished, actionable datasets.

Workflow of Olewave's speech data cleaning pipeline

Our pipeline offers several advantages.

  • Effective. It produces validated speaker labels and transcriptions, accurate word timestamps and not-overconfident confidence scores compared with Whisper and other open-source tools.
  • Robustness. It handles improvised conversational speech, including scenarios with speaker overlap and transcripts containing ASR errors.
  • Extensible. It leverages optional metadata and can be upgraded to incorporate additional modality for increased label reliability. The pipeline also supports plug-and-play integration of various Olewave's or client's own label tagging models (e.g., emotion, semantics, …).
  • Efficiency. It runs quickly and is cost-effective, as it requires no or little GPU resources.

Additionally, if your goal is to have human annotators refine Automatic Speech Recognition (ASR) results, the output of our pipeline can significantly reduce labeling costs in two ways.

  • Precisely highlighting words with accurate timing information, enabling annotators to quickly locate and review mumbled or unclear segments without repeatedly listening to the entire audio.
  • Guiding annotators to focus on words with mid-range confidence scores, minimizing the need to review every word and streamlining the correction process.

By providing these targeted insights, our pipeline enhances efficiency, reduces manual effort, and ensures a more cost-effective annotation workflow.

Below are the visualized examples of the pipeline's output, showcasing speaker label, word-level timestamps and confidence scores.

Pipeline output showing speaker labels, word-level timestamps and confidence scores
Fig 1. The conversation comes from real-world interactions. People uploaded the transcripts and added the speaker labels by hand, so no ASR or speaker diarization was involved. The accompanying JSON file includes detailed transcriptions, with speaker time intervals, conversation transcripts, word-level timestamps, and confidence scores. Phone-level timestamps and confidence scores are available upon request too.
Postprocessing of noisy spontaneous speech with per-word pronunciation scores
Figure 2. An example of the postprocessing of noisy spontaneous speech, where the value beneath each word represents its pronunciation score, which is closely related to speech assessment. Here is what the scores of three words show. a) The word 'together' was pronounced as 'togeth-'. The ending '-er' is not present, and the '-o-' vowel is so short that it almost disappears. b) The starting word 'it' is barely audible, though a fricative phone shows on the spectrogram. Its low score of 0.47 means the word is likely missing. c) The inserted word 'lt' at the end was never said. It appears because the transcript wrongly includes '&lt', the '<' symbol used in HTML. Its very low score of 0.13 marks it as an inserted word, which our data cleaning pipeline can remove.

It is widely recognized in both academia and industry that large End-to-End (E2E) frameworks and large E2E ASR models have inherent limitations when it comes to producing accurate word-level timestamps and reliable word-level confidence scores, respectively.

To address these limitations, we leverage our deep expertise in non-End-to-End speech-to-text alignment techniques and have developed sophisticated procedures that incorporate metadata information. This approach allows us to effectively clean non-spoken content (e.g., filler words, background noise transcriptions) from transcripts, ensuring higher accuracy and reliability in the final output.

Here is a snippet of word-level json output of the data pipeline. The 'speaker' field indicates the id of the speaker in this recording. The 'start_time' and 'end_time' fields are in seconds indicating the time span of the speaking speaker. The 'block' field contains one or multiple consecutive utterances from the same speaker. Each utterance has its own starting time, ending time, transcript, speaker overlap indicator, and confidence score. When an 'overlap' field is true, it means the current segment has a speaker overlap with adjacent segments. The confidence score ranges from 0 to 1.

{
        "speaker": 0,
        "start_time": "47.18",
        "end_time": "49.83",
        "block": [
            {
                "start_time": "47.18",
                "end_time": "49.83",
                "transcript": "music-related jobs compared to New York and LA.",
                "overlap": false,
                "word_details": [
                    {
                        "start_time": "47.18",
                        "end_time": "47.53",
                        "word": "music",
                        "confidence": "0.97"
                    },
                    {
                        "start_time": "47.53",
                        "end_time": "47.89",
                        "word": "related",
                        "confidence": "0.79"
                    },
                    {
                        "start_time": "47.89",
                        "end_time": "48.44",
                        "word": "jobs",
                        "confidence": "0.98"
                    },
                    {
                        "start_time": "48.44",
                        "end_time": "48.90",
                        "word": "compared",
                        "confidence": "0.96"
                    },
                    {
                        "start_time": "48.90",
                        "end_time": "48.96",
                        "word": "to",
                        "confidence": "0.17"
                    },
                    {
                        "start_time": "48.96",
                        "end_time": "49.08",
                        "word": "new",
                        "confidence": "0.97"
                    },
                    {
                        "start_time": "49.08",
                        "end_time": "49.37",
                        "word": "york",
                        "confidence": "0.98"
                    },
                    {
                        "start_time": "49.37",
                        "end_time": "49.49",
                        "word": "and",
                        "confidence": "0.92"
                    },
                    {
                        "start_time": "49.49",
                        "end_time": "49.83",
                        "word": "la",
                        "confidence": "0.56"
                    }
                ]
            }
        ]
    },