libsigrokdecode now supports the spdif decoder.
The Sony/Philips Digital Interface Format (S/PDIF) is a (nowadays standardized in IEC 60958) digital audio protocol that is used in various devices and supported by a number of ICs, such as the TI PCM2707 and many others.
A short description of the protocol is available on the respective wiki page, along with pointers to further reading.
Thanks a lot to Guenther Wenninger for contributing the decoder!