Overview, Timecode Settings, Clock Source

Timecode

Overview

The HD-P2 has a wide range of timecode features. It can read incoming linear timecode (LTC) and has many functions including freewheeling, trigger on frame number, and timecode offset. The HD-P2 can also resolve its audio clock to a range of sources including LTC in and video in.

Very briefly, timecode operation works this way (details in the following sections):

1.Enable timecode on the Project Menu/Settings screen.

2.Adjust the timecode settings as needed.

3.Go into timecode chase mode by pressing the TIMECODE key. The TIMECODE indicator will reflect the state of incoming timecode (blinking if there is no timecode, solid with good timecode). The position on the audio timeline is now controlled by the LTC.

4.Start a timecode operation by pressing the PLAY or REC key. The REC indicator will blink until the op-

eration is triggered by incoming timecode. Once triggered, any blinking light will stay on solid.

5.The operation is stopped when the STOP key is pressed, or if power or storage space is low, or if LTC has hit the end of its 24-hour timecode day. If FreeWheel is not infinite (see below), then the op- eration will also stop if timecode is stopped.

6.Leave timecode chase mode by pressing the TIMECODE key. The TIMECODE indicator goes out and the transport keys and the SHUTTLE/DATA wheel once again control the position on the audio timeline.

7.When timecode is disabled on the Project Menu/ Settings screen, the TIMECODE key is no longer ac- tive.

There are many variations to how timecode works on the HD-P2, as controlled by the Timecode Settings screen.

Timecode Settings

Timecode operation on the HD-P2 is disabled by default. You cannot access the Timecode Settings menu screen until timecode is enabled. Go to the Project Menu/Settings screen, select the Timecode menu item and change it from DIS to EN to enable timecode. Then select the Timecode Settings menu item and press the SELECT key to enter the Timecode Settings screen which looks similar to Figure 33.

Clock Source

This menu item is a duplicate of the Clock Source field on the Project Menu/Settings screen. There is only one audio clock source and changing either one affects the other. This menu is included in the Timecode Settings for convenience.

The possible audio Clock Source values are:

•Internal – The audio clock is crystal-controlled and generated by the HD-P2. Use this only if the HD-P2 is to be the audio clock master in your sys- tem, with its S/PDIF digital audio output used to synchronize other audio gear.

•Word – The BNC input can also be sent a standard TTL-level word clock for audio clock sync.

•S/PDIF – The audio clock rate can also be derived from an incoming S/PDIF digital audio signal.

•LTC – The HD-P2 will lock its audio clock to the incoming LTC, always keeping it in sync to the LTC rate. Please note that even with the audio clock rate locked to incoming LTC, the audio clock can still “drift” with respect to the LTC if it is discontiguous or if there is a mismatch between the expected and received LTC formats (e.g. drop vs. non-drop frame).

Figure 33 - Timecode Settings Screen

•Video – A variety of video formats can be fed into the BNC input and used for audio sync, including composite or blackburst NTSC and PAL, and tri- level sync from HDTV systems. Note that the Frame Rate (described below) must be correctly set to match the incoming video material.

The audio clock source and frame rate must be set cor- rectly and fed valid signals to avoid “drift” between the LTC and the audio clock.

Frame Rate

This field lets you specify the expected incoming LTC (and video) frame rate, as well as frame encoding in Drop Frame (DF) and Non-Drop (ND) frame systems.

•23.976 – Some HDTV setups use a “pull-down” ver- sion of 24 frame-per-second video. While the video

TASCAM HD-P2 Owner's Manual 21