Hello all,
I have a requirement wherein I may have to identify (not decode) the compressed audio format (AC3/DTS/MPEG etc.) carried by an SPDIF bitstream, using a PIC microcontroller.
Assuming that a phase-locked synchronous clock signal is already available to the microcontroller, how would one possibly go about doing the above? The MCU clock is at 64MHz and interrupt inputs are available.
Thanks in advance.
I have a requirement wherein I may have to identify (not decode) the compressed audio format (AC3/DTS/MPEG etc.) carried by an SPDIF bitstream, using a PIC microcontroller.
Assuming that a phase-locked synchronous clock signal is already available to the microcontroller, how would one possibly go about doing the above? The MCU clock is at 64MHz and interrupt inputs are available.
Thanks in advance.
When in the SPDIF datastream such formats are considered encoded and are preceded by an identifying preamble. The preamble for each kind of compressed format is in the IEC61937-x spec where x is the number for each compressed format. Some of the more advanced SPDIF i/f chips are capable of detecting this preamble and signalling accordingly.
Thank you for that, rfbrw. I managed to find details of the preamble in Tables 1 and 2 of IEC-61937-2, also attached below for anyone having similar needs.