Browsing, indexing and automatic transcription of lectures for distance learning

This paper presents a complex system developed to improve the quality of distance learning by allowing people to browse the content of various (academic) lectures. The system consists of several main modules. The first automatic speech recognition (ASR) module is designed to cope with inflective Czech language and provides time-aligned transcriptions of input audio-visual recordings of lectures. These transcriptions are generated off-line in two recognition passes using speaker adaptation methods and language models mixed from various text sources including transcriptions of broadcast programs, spontaneous telephone talks, web discussions, thesis, etc. Lecture recordings and their transcriptions are then indexed and stored in the database. The next module, client-server web lecture browser, allows to browse or play the indexed content and search in it.