Transcribing and Aligning Conversational Speech: A Hybrid Pipeline Applied to French Conversations

With the advent of transformer based models, the use of fully automated ASR-pipelines in a real-world context has come close to a reality. However, for faithful transcription of conversational speech, there remain challenges both in terms of the content predicted by these models (hallucinations, unintended normalizations of disfluencies and transcriptions of background noises) and in terms of alignment accuracy. In this paper we present a hybrid ASR-pipeline which augments transformer models with other algorithms in order to transcribe conversational data. Through experiments on two French datasets, we show that: 1) VAD preprocessing can significantly improve transcription quality as well as word level temporal alignment, 2) prompting can reduce unintended normalizations of disfluencies, 3) heuristic-based detection of untranscribed sounds can further improve alignment quality. We conclude that our hybrid pipeline is an efficient way to improve and augment existing ASR-models.