  Speaker-independent VSR is a complex task that involves identifying spoken
words or phrases from video recordings of a speaker's facial movements. Over
the years, there has been a considerable amount of research in the field of VSR
involving different algorithms and datasets to evaluate system performance.
These efforts have resulted in significant progress in developing effective VSR
models, creating new opportunities for further research in this area. This
survey provides a detailed examination of the progression of VSR over the past
three decades, with a particular emphasis on the transition from
speaker-dependent to speaker-independent systems. We also provide a
comprehensive overview of the various datasets used in VSR research and the
preprocessing techniques employed to achieve speaker independence. The survey
covers the works published from 1990 to 2023, thoroughly analyzing each work
and comparing them on various parameters. This survey provides an in-depth
analysis of speaker-independent VSR systems evolution from 1990 to 2023. It
outlines the development of VSR systems over time and highlights the need to
develop end-to-end pipelines for speaker-independent VSR. The pictorial
representation offers a clear and concise overview of the techniques used in
speaker-independent VSR, thereby aiding in the comprehension and analysis of
the various methodologies. The survey also highlights the strengths and
limitations of each technique and provides insights into developing novel
approaches for analyzing visual speech cues. Overall, This comprehensive review
provides insights into the current state-of-the-art speaker-independent VSR and
highlights potential areas for future research.
