After successful completion of the course, students are able to understand and apply the methods described unter the item "Lehrinhalte". This includes the design of vector quantizers or the implementation of model-based source codecs that are used in mobile phones.
Source coding is a key technology for mobile radio, MP3, JPG, and video transmission. We discuss the theoretical foundations for lossy source coding (rate distortion theory and asymptotic quantisation theory) as well as practical coding schemes and vector quantisation. For practically relevant correlated source signals we extend the theory and we also discuss practical code design that are structurally based on results from information theory. Those schemes include predictive coding, which is used e.g. in speech transmission in mobile radio, as well as subband coding, which is part of MP3-Audio.
The course will be help online. Slides are presented which are available under
https://www.nt.tuwien.ac.at/wp-content/uploads/2021/08/SourceCodingLec.pdf
Students are supposed to work through the material in advance of the lectures; details of the schedule are given in the lectures slides.
Additional tutorial problems including solutions are available here
https://www.nt.tuwien.ac.at/wp-content/uploads/2021/12/SpeechCoding_Tutorials.tar.gz
The archive also contains a set of slides about speech coding, audio samples and the source code of the AMR Speech Codec.
If time permits: As an every-day application, in the last lecture will will dive into some details of Adaptive Multirate Speech Coding (AMR):
The AMR-Codec is standardized for mobile radio in Europe (and beyond). We look at release 12, that is 3GPP TS 26.090 V12.0.0 (2014-09) which is available here. One has to look at the "Specifications", and the "Technical Specifications", select "26-Codecs" search, and find the number 26.090 in the pop-up list. Then click the "goggles"-symbol to the right and pick version 12: here we are. This is pretty tedious, but it should give an impression how complex (and large) the world of 3GPP standards is. We have just found the written specification.
The C-Code for this AMR-Codec is also available: same website, same procedure, but now for the numer 26.073.
In the archive linked above the pdfs, the source code and a variety of audiosamples are available for download. The audio samples are converted to wav while the codec software requires raw data of signed integers at 16bits per sample (8kHz sampling rate).
The lectures are delivered online via Zoom in blocked format on Tuesdays, 2pm
The Zoom-Link (computer, tablet or smartphone) to the lectures is
https://tuwien.zoom.us/j/98293283653
Schedule of lectures for the winter term 2021/2022: from 14:00--16:30 on each of the following days:
5. Oct., 12. Oct., 2. Nov, 9. Nov., 16. Nov., 14. Dec.
Desirable prior knowledge: discrete-time signals and systems, basics of information theory.
There are no formal compulsory requirements.
