This paper presents a procedure to easily obtain phonetic data from subtitled YouTube videos in English. Called PEASYV (Phonetic Extraction and Alignment of Subtitled YouTube Videos) and based on a UNIX shell script, this procedure makes it possible to obtain fine-grained phonetic and phonological data from any subtitled videos posted on YouTube. It uses two aligners, P2FA [1] and SPPAS [2], to generate Praat [3] TextGrids for each video. These TextGrids contain tiers specific to each aligner, with segmental, syllabic and lexical alignments. SPPAS tiers also contain prosodic information. After describing the procedure and the generated files, a case study of a YouTube channel on English pronunciation is presented, in order to assess the quality of the alignment: the formants of the monophthongs from the channel's 452 videos, amounting to more than 179 hours of spontaneous speech, are analysed. The potential alignment errors, along with their prevention, are then discussed.