Hi group! I'm pretty new to the list, so please excuse me if this topic is already old and dead. Around the web I hve seen people having trouble with trackmarks when recording from their PC soundcards with digital out. We all know that when using digital out on a CD player this works fine. So what's the difference? When data is encoded on a CD there is additional info added in the so called subchannels. Subchannels are one bit from each word put together to a new word. There are eight subchannels: P, Q, R, S, T, U, V and W. The Q subchannel holds all info about tracks, and time on the CD. Though I'm not familiar with the encoding of MDs (yet!) I realise that this information must also be present on the MD. When using a CD writer connected to your conputer the subchannel info is generated by the CDR firmware durning recording. You can control this info with the CD writing software, so that tracks and indexes end up where you like. When recording to our MDs we have no computer to control this so all the data is generated by the firmware in the MD. BUT! When recording from CD with digital out trackmarks are somehow transfered to the MD. This must appearently me through the S/PDIF interface since this is the only connection we have between the CD and the MD. The S/PDIF interface encoding also have subchannels that carries extra information. Bit 29 and bit 30 of each subframe carries this data. Bit 30 is the "Channel-status" subchannel, and is specified in detail in the S/PDIF specs. I can find no info here that could tell when a new track starts. Bit 29 is the "User" subchannel. One description I've found on the web describs it like this: "User Bits. Here the designer of the device may transmit system-exclusive data. In the meantime this has become the place of START or SKIP IDs." So it seems like this is where the information on when a new track starts is transmitted. There seems to be a "standard" for this encoding that goes beyond the S/PDIF interface standard.So far I've found nothing on how information is encoded in this! ! User subchannel. Can anyone lead me to a source or post something here? I've seen postings that common soundcards like Soundblaster Live! and Hoontech 4D Wave NX can't access this User subchannel. If so then we will have a hard time solving the trackmarkning problem when recrding from e.g Winamp. (3 sec gaps is a solution, but not for mixed music and not if you don't like 3 sec gaps.) When hooking up a CD players S/PDIF output directly to a soundcard the soundcard just acts like a electrical (TTL?) to optical converter and the trackmarking should work fine. (Havn't tried though, because my CD don't support digital out.) The problem remains if your using a SCSI CD and recording digitaly through the SCSI bus and your soundcard. I do this with my Plextor CD and Plextor Manager 2000 player. It doesn't seem to work with other CD players such as the Windows 98 "built in". So what's the point with this long boring posting? : Have I got things right, or is this just a big pile of BS I've written above? Where can I find a specification on the encoding of the information in the S/PDIF user subchannel (bit 29) ? Can somone confirm that bit 29 and the User subchannel can't be accessed by common soundcards? Best regards, Lars Soderman Stockholm, Sweden ----------------------------------------------------------------- To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
