multikigor Posted February 17, 2007 Report Share Posted February 17, 2007 Hi ,Is it possible to build MTC (Midi Time Code) to LTC (Longitudinal timecode) converter ,with LCD that shows current position and timecode format, based on MIDIBOX?Thanks! Quote Link to comment Share on other sites More sharing options...
stryd_one Posted February 20, 2007 Report Share Posted February 20, 2007 Sure is, you just need to have some skills in C.Welcome aboard! This should probably go in the design concepts area of the forums though.... I have to test out my green stars now, thanks for the opportunity ;) Quote Link to comment Share on other sites More sharing options...
audiocommander Posted February 20, 2007 Report Share Posted February 20, 2007 öhm...LTC timecode is essentially an audio signal around 2 kHz in frequency. This signal can be distributed by standard audio wiring' date=' connectors, distribution amplifiers, and patchbays, and can be ground-isolated with audio transformers. LTC can also be distributed via 75 ohm video cable and video distribution amplifiers, although the voltage attenuation caused by using a 75 ohm system may cause the signal to drop to a level that can not be read by some equipment.[/quote']This sounds like no trivial task to me (but I did not know LTC before I looked it up). Are you sure you can't use MTC? As far as I understood the quick search I did, both MTC and LTC are another kind of SMPTE, whereas MTC is for MIDI-transmission (digital binary signals) and LTC for A/V-transmissions (eg. film or musical waveforms).Best regards,Michael Quote Link to comment Share on other sites More sharing options...
smashtv Posted February 22, 2007 Report Share Posted February 22, 2007 Hi guys!Just thought I would jump in here with some info.....sorry if I am preaching to the choir ;)LTC is simply timecode with absolute position information in every frame of data. In other words, if you stop playback at five seconds somewhere in that frame of timing data you will find something that looks like "00:00:00:05:000".Your DVcam, Older multitrack tape decks, Video editors, etc. all use LTC, but vastly different physical layers/methods to encode and read the timing info. DVcam mixes the data in with the image data (DV format), Multitrack "stripes" it to an unused tape channel (SMPTE-formatted stripe via FSK (Frequency Shift Keying)), Pro video format(s) have it in the non-image portion of the video frame (can be proprietary but usually SMPTE format).In the real world, most LTC devices designed to swap timing with other devices read/generate SMPTE format timecode data.MTC is simply SMPTE timecode data formatted as sysex messages. This dumps a lot of data onto the MIDI bus, so any MIDI I/O used to carry MTC should not be used for any other MIDI data if you want a solid sync lock.The other common sync scheme is "MIDI Clock". The best way to think of this is as a combination of tempo information and Song Position Pointer data.MIDI Clock is relative, meaning if you stop playback at five seconds the timing data has something similar to x Bars:x Beats (making it relative to the start of the song and the tempo). Nothing in there about 5 seconds....The Wikipedia quote about LTC is not entirely right, it is describing one specific physical implementation/method of passing timecode between devices out of many (the Wikipedia name is describing timing connections common to pro video gear and a lot of audio gear that is designed to interoperate with said video gear)Sorry if my descriptions create confusion, my blood/coffee ratio has not been optimized yet today. ;DSo multikigor, what specific devices are you trying to sync? There might be an off the shelf solution already.Best RegardsSmashTV Quote Link to comment Share on other sites More sharing options...
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