Multi-Modal Pre-Training and Mid-Training Strategies for Improved Automatic Speech Recognition

Core Concepts

Combining multi-modal pre-training with a novel mid-training translation task leads to significant improvements in automatic speech recognition performance.

Abstract

The paper explores a multi-stage multi-modal pre-training approach for automatic speech recognition (ASR). The key insights are:

Audio-visual pre-training is effective in improving ASR performance compared to randomly initialized models, across different pre-training datasets and techniques.

Introducing a mid-training stage using a speech translation task further boosts performance, with the best results obtained using English-Italian translation. This suggests that choosing complementary languages for mid-training can be more beneficial than using languages closer to the target language (English).

The impact of the pre-training dataset composition is significant - the clean speech dataset LRS-3 outperforms the larger but more diverse Voxceleb2 and Kinetics datasets in the pre-training only setting. However, the Kinetics dataset benefits the most from the mid-training stage, indicating that models trained on non-speech data have the most to gain from the language-representation alignment provided by the mid-training task.

The masked autoencoding (MAE) pre-training approach outperforms contrastive learning (CLR) and the combination MAE+CLR for the ASR task, suggesting MAE is better at capturing the local information required for speech recognition. However, MAE+CLR performs best when aggregating performance across a mix of global and local downstream tasks.

The mid-training translation task provides the most benefit for the CLR pre-trained models, aligning their more global representations with the language modeling required for ASR.

Stats

The Kinetics-600 dataset has 966 hours of audio-visual data for activity recognition, with a focus on the environment or instrument used.
The Voxceleb2 dataset provides 2380 hours of multi-lingual speaker recognition data with challenging acoustics and comprehensive lip and facial movements.
The LRS3 dataset features 346 hours of clean, multi-modal spoken sentence data from TED and TEDx videos.
The MuST-C dataset is used for the mid-training speech translation task, with German, Italian and Dutch as the target languages.

Quotes

"Recent works in the ASR community have corroborated these results. Shi et al. (2022) and Hsu and Shi (2022) demonstrated that pre-training on large-scale audio-visual data (or audio-only data), in the form of lip-reading videos, leads to better performance on the lip-reading task. Chan et al. (2022) showed that exposing models to video data during pre-training led to performance improvements not only when visual input is available at train-time, but also when only audio is available at test-time."
"We show that pre-training with audio-visual data, particularly data from speech-specific audio-visual datasets can improve word error rate (WER) up to 30.8% relative compared to randomly initialized baseline models on speech-only test data."
"We introduce a novel mid-training stage between the pre-training and fine-tuning steps, using speech translation as the mid-training task. The mid-training stage improves WER by 38.45% relative on the Librispeech test-clean dataset, and by 26.18% relative on the test-other dataset compared to audio-visual pre-training only baseline."

Key Insights Distilled From

Multi-Stage Multi-Modal Pre-Training for Automatic Speech Recognition

by Yash Jain,Da... at arxiv.org 04-01-2024

https://arxiv.org/pdf/2403.19822.pdf

Deeper Inquiries

How would the performance of the proposed multi-stage multi-modal approach compare to state-of-the-art ASR models that use large-scale speech-only pre-training

The performance of the proposed multi-stage multi-modal approach, as outlined in the context provided, would likely compare favorably to state-of-the-art ASR models that use large-scale speech-only pre-training. The key advantage of the multi-stage multi-modal approach lies in its ability to leverage diverse data sources during pre-training, leading to more robust representations. By incorporating both audio and visual modalities in the pre-training process, the model can learn to discern speaker-specific patterns, global noise patterns, and other complex features that are crucial for accurate ASR. This comprehensive pre-training strategy is likely to result in improved performance compared to models that rely solely on speech-only pre-training. Additionally, the inclusion of a mid-training stage further refines the learned representations, aligning them more closely with the requirements of the downstream ASR task. This iterative approach to training allows for a more nuanced and effective learning process, potentially outperforming traditional large-scale speech-only pre-training models.

What other mid-training tasks beyond speech translation could be explored to further improve the alignment between the pre-trained representations and the downstream ASR task

Beyond speech translation, several other mid-training tasks could be explored to further enhance the alignment between pre-trained representations and the downstream ASR task. One promising avenue is the incorporation of tasks related to speaker identification and speaker/source separation. By training the model to distinguish between different speakers or separate overlapping audio sources, the model can develop a deeper understanding of the audio input, leading to improved performance in ASR tasks. Additionally, tasks such as text-to-speech conversion, where the model learns to generate speech from text inputs, could also be valuable for enhancing the model's ability to process and generate spoken language. Exploring these additional mid-training tasks can provide further opportunities to refine the learned representations and optimize the model for ASR applications.

How generalizable are the insights from this work on the impact of pre-training dataset composition and the benefits of mid-training to other multi-modal tasks beyond ASR, such as video understanding or robotics

The insights gained from this work on the impact of pre-training dataset composition and the benefits of mid-training are likely to be highly generalizable to other multi-modal tasks beyond ASR, such as video understanding or robotics. The principles of leveraging diverse data sources for pre-training, optimizing representations through mid-training tasks, and fine-tuning for specific downstream tasks are fundamental to the field of machine learning and can be applied across a wide range of applications. For video understanding tasks, the multi-modal pre-training approach can help models learn to extract meaningful information from both visual and audio inputs, improving performance on tasks such as action recognition, object detection, and video captioning. In robotics, the insights from this work can inform the development of models that can effectively process multi-modal sensor data to perform tasks like object manipulation, navigation, and human-robot interaction. By adapting the concepts and methodologies presented in this study, researchers in various domains can enhance the performance and robustness of their multi-modal systems.