Methods and systems for training one or more neural networks for transcription and for transcribing a media file using the trained one or more neural networks are provided. One of the methods includes: segmenting the media file into a plurality of segments; extracting, using a first neural network, audio features of a first and second segment of the plurality of segments; and identifying, using a second neural network, a best-candidate engine for each of the first and second segments based at least on audio features of the first and second segments. A best-candidate engine is a neural network having a highest predicted transcription accuracy among a collection of neural networks.