LTCReader -- iPhone / iPod touch application, for decoding a LTC (linear time code) audio stream and displaying the timecode on the screen including jam sync according to SMPTE teveision standard (SMPTE 12M-1-2008)

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The display shows an incoming LTC signal.

Above is a timecode displayed generated by a LTC generator and feeded into the mic input of the iPod (using an line adapter). The system can also jam sync and decode reverse running LTC.

You need either a dock adapter with a line input or some microfon adapters using the dock connector do have a line or mic input or cable adapter using the headphone microphone as input.

The display always shows the waveform, and is useful if you want to check for the LTC coming from an unknown source for example. Its automatically synced to the data stream, if a valid sync word is detected, otherwise a free running display results using the last valid LTC (if set to JAM sync)

LTC is used for synchronising professional camera equipment and editing equipment for example. A Jam modus allows for grabbing a LTC and disconnecting after this.

As a user wish we provide a small schematic on how to build a connector cable. Be very careful when building this adapter and measure the output signal not to exceed the maximum input of your deviceas this is microphone level. Attention ground and signal position on the connector are according to a documentation we found on Wiki and not officially approved. The 1.2 kOhm resistor is important so that the device can sense the input.

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option menue allows for different time bases

You can also generate a test audio signal either NTSC or PAL (free running not in sync)

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large display

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LTC with a PAL signal and 25fps

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A standard wave is presented instead a LTC, the last valid LTC is still running using the JAM modus.


a small part of the LTC wave file showing the 12 sync pulses. In total 80 bits per frame are transmitted,

(C) 2021 MultiMediaStudio Dipl. Ing. Rolf-Dieter Klein - DM7RDK