Preserving captioning through video transcoding

摘要

Methods of preserving captioning information in an input video stream through transcoding of the input video stream include extracting caption data from the input video stream, translating the caption data into at least one output caption format, packaging the translated caption data into data packets for insertion into a video stream, synchronizing the packaged caption data with a transcoded version of the input video stream, receiving a preliminary output video stream that is a transcoded version of the input video stream, and combining the packaged caption data with the preliminary output video stream to form an output video stream. Related systems and computer program products are also disclosed.

主权项

1. A method, comprising:
parsing an input video stream to determine a presentation order of encoded frames in the input video stream; if audio data is present, processing the audio data independently of the input video stream and caption data; reordering the caption data into the presentation order, the caption data extracted from the input video stream; assigning time stamps to the caption data; translating the caption data from closed caption data into an output caption format, the output caption format being a different format than a format of the closed caption data; providing a target bit rate based on an amount of the caption data to be inserted into a preliminary output video stream; transcoding the input video stream, excluding the caption data, into the preliminary output video stream at the target bit rate, a frame rate of the input video stream being different from a frame rate of the preliminary output video stream; reordering the caption data in the output caption format into a coded order of encoded frames in the preliminary output video stream, based on the time stamps of the caption data; and writing the caption data in the output caption format to a same file as the preliminary output video stream.