TMS: Track Marker Support
CD Track / DAT Start ID Transfer and Emphasis Recognition
*Note: TMS is not supported by the RME DIGI32 series, DIGI9652, or DIGI9636
RME sound cards offer several worldwide unique features, among them the ability to transfer all Channel Status bits to the recording software. These additional data offer a host of useful functions, demonstrated by DIGICheck®, our (worldwide unique...) utility for test, measurement and analysis of the digital data stream. Of highest interest is the possibility to gain useful information out of the so called user bits. This task is performed by TMS, the Track Marker Support of the RME sound card line. TMS allows every recording software, no matter which platform, for example to detect CD track numbers and DAT start-IDs while recording, and to set a marker at the right place.
This TECH INFO describes the principle of transferring the additional data. All RME cards support TMS with the exception of the DIGI32 series, the DIGI9652, and the DIGI9636. Cards of other manufacturer's having a DSP on board are in general enabled to also implement TMS. Therefore we expect this method to show up in other cards too, especially as we don't ask for any license fees. We only ask for a copyright notice in the corresponding product to clearly state that TMS is a technology from RME.
Technical background: the 32 bit technology
As far as we know, RME sound cards are the first and only audio cards to allow recording of the complete 32 bit digital audio data stream. Besides the usual 24 audio bits P, C, U and V bits are also transmitted. That's 28? Right, the first 4 bits form the preamble. This synchronization signal isn't needed anymore after a successful receiving and decoding of the signal. To use the data of the PCUV-bits the start of the block must be known. Therefore the data stream sent from the sound card to the record program also includes the CBL (channel block start) signal.
RME sound cards transmit the data in the following format to the recording program:
X = Audio data
0 = unused B = CBL P = Parity C = Channel
Status U = User Bit V = Validity Bit
Advantages of this method
This method has several advantages. Modern cards nearly
exclusively use the Crystal Receiver CS8412/8414, which make all the above
signals available (only the delay of 2 samples has to be added in case all
signals are taken directly from the chip.) The 4 byte/s mode is available
in nearly every professional recording software. A coarse detection of the
TMS capability can be done already with this mode, as cheap soundcards don't
support 4 byte mode, and sure will not do so in the near future.
Disadvantages of this method
As mentioned the decoding of the user bits for a detection
of CD-track or DAT start-ID is done in the corresponding record program.
The main reason such a method as TMS wasn't introduced earlier is probably
that most programmers and engineers don't know how to retrieve the useful
information out of the data stream. To prevent TMS from being born dead
RME provides a free source code to all software companies, including the
routines demonstrated in DIGICheck. Based on this exemplary code an implementation
is no problem anymore and done in less than a day.
TMS in practice
For a successful integration of TMS into a recording software, and for achieving an efficient and highly usable interface, some basic ideas and methods should be taken into account.
Due to the fact that we constantly get requests from our customers about an Emphasis detection during recording RME now also offers an Emphasis detection, included the TMS source code. After a signaling of this bit the recording software in principle has two choices:
Method 1 suffers from a big disadvantage: At playback normally no automatic control is possible, so the user has to manually set the Emphasis bit in the settings dialog of the RME card. Additional the recorded wave file can't be marked clearly as 'pre-Emphasis', which might cause a later processing without de-Emphasis. Method 2 removes all problems that might occur with pre-Emphasis material, as after the recording the audio material is no longer emphasized, but turned into 'normal' material that no longer needs any special treatment.
TMS is an easy to use technology for direct transfer of
CD track number and DAT start-IDs, and the detection of emphasized audio
material. Functions strongly demanded (not only) by professionals.
Copyright © Matthias Carstens, 1999
Copyright © 2002 RME. All rights reserved.
RME is a registered trademark.