These are chat archives for Opendigitalradio/mmbTools

7th
Apr 2016
Gabriel
@vvombat
Apr 07 2016 09:12
Every time I need to listen for audio glitches, the audio programme I'm using for the test plays some strange acoustic percussion music, or some weird electro, and I never know if there are glitches or not! :facepalm:
That's why I use "the good old" Beethoven. ^^
Gabriel
@vvombat
Apr 07 2016 09:49

Maybe somebody in here can answer these two questions:

1) I don't get the difference between "stream mode" and "packet mode" in the MSC. Stream mode means a consecutive number of CUs in one CIF belong to one subchannel. The subchannel is defined as usual in one FIG (MCI / SI). But packet mode means multiple data service components can be carried in one subchannel -> but where is the beginning of each packet defined? And is this used in the mmbTools? I mainly work with ORD-DabMux and in the mux_frame() the input data is read once per subchannel as a block directly from input.
2) (ETSI EN 300 401 6.2.1) FIG0_1 describes the subchannel organization. It has a field Start Adress (0-863) which describes the first CU of the sub-channel. But it has no field to describe which CIF?! Are there different FIGs to describe the start of a sub-channel in transmission modes 1 & 4 (4 CUs / 2 CUs)?

Maybe somebody knows this without to much research(!), I don't want to waste your time. :worried:

Matthias P. Braendli
@mpbraendli
Apr 07 2016 21:00
I'm afraid I cannot help you much without diving into the spec again. Packet mode also has quite a few mysteries to me...