5. Inserting audio into video
When inserting a digital audio stream into a digital video stream, the first difficulty that arises is the difference in structure between the two streams. While both appear to be a succession of fixed-rate bits, derived from the fixed-rate sampling of an analog signal, the underlying temporal structure is very different. The video signal is made up of lines, separated by line break intervals. After digitization, this structure is respected, and the digital stream alternates between a packet of bytes corresponding to a video line and a packet of empty bytes, corresponding to the line returns. It is into these empty packets that the audio signal is inserted.
A second difficulty arises from the relationship between video frames and audio samples. The ratio between the number of video lines per second and the number of audio samples per second is not a whole number....
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Inserting audio into video
Conclusion and benchmarks
Bibliography
General works
- WATKINSON (J.) - The Art of Digital Audio. - Focal Press (1991).
- BALLOU (G.M.) (éd.) - Handbook of Sound Engineers : The New Audio Cyclopedia. - Butterworth-Heinemann (1998).
In Engineering...
Norms, standards
- AES Recommended practice for digital audio engineering – Serial transmission format for two-channel linearly represented digital audio data - AES3-2003 -
- Specification of the digital audio interface (the AES/EBU interface) - EBU Tech. 3250-E - 2004
- Interface audionumérique pour les studios de radiodiffusion - UIT-R BS.647-2 - 03-92
- AES information document for digital audio engineering – Transmission...
Organizations
Audio Engineering Society (AES) http://www.aes.org
American National Standard Institute (ANSI) http://www.ansi.org
European Broadcasting Union (EBU)
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