01 - Playout

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01 - Playout


The Playout menu is the default menu when you enter the Player. The controls on the menu are only available if there is a valid SDI setup. The Playout module enables you to directly control a connected Video Tape Deck (VTR) to play out the currently selected range in the Player, or even an entire Construct, to a specified Timecode. Sequences can be output to NTSC, PAL, or any HD format; options include3:2 pull-down for 24 to NTSC conversions and 24 to 25 fps for PAL conversions.

Tip: You can output just a portion of a Construct by setting the IN and OUT points to define the range that will be used by Playout.

Playout requires an SDI card and the deck control protocol is Sony standard, via an RS-232 connection. An RS-422 to RS-232 converter is required when connecting the serial port from the SCRATCH system to the remote input of the VTR. The details of setting up a valid VTR connection are discussed first and the the Playout menu is covered next.


There are two connections that must be made between the SCRATCH system and the VTR. First, the video output from the SDI card’s OUTPUT is connected to the VTR’s SDI INPUT. This is done through a standard video BNC-connector cable.

Second, the connection is the control link that allows SCRATCH to communicate with the VTR. This connection is made from a serial port (Windows) / device (OS X) of the SCRATCH system to the REMOTE IN port of the VTR. The serial port uses a communication protocol, called RS-232, while the VTR uses a protocol called RS-422. In order for this connection to be made properly, the RS-232 signal, coming from the SCRATCH system, must be converted to an RS-422 signal the VTR will understand. This is done using an RS-232 to RS-422 converter.

Tip: Alternatively to using the computer's (physical) serial port you can use a USB to RS-422 converter, which creates additional (virtual) serial ports.

Once the physical connections have been made you configure SCRATCH through the VTR Configuration dialog. Click the Configure button in the Playout menu to open this dialog.

First thing to set is the Com port SCRATCH should use.

Note: To determine the name of the device to use on OS X, you open a terminal and type the command ls -l /dev/cu* This will list all available devices among which the device you use to set the "port" setting for communication with the VTR.

SCRATCH can maintain settings for multiple decks if connected to different serial ports. Once connected SCRATCH will show the name of the deck - if SCRATCH does not recognize the deck you can update the name.


For frame-accuracy you can adjust the values for video, GFX and audio to adjust the offset for playback of the deck, and playback of the Construct, respectively. By adjusting these values, you can ensure the record IN point on the record deck is at the correct frame (controlled by video ), audio sample (controlled by audio) and the correct source frame from SCRATCH is being recorded to the proper Timecode (controlled by gfx).

To test frame-accuracy, use material that is easy for distinguishing unique frames, a countdown, or burned-in timecode, for example and lip-sync audio with on regular interval repeating sounds. Do a test layoff to tape and then review the tape.

If the edit point is incorrect, adjust the video value, save the file and re-try the layoff. Once the edit point is correct, evaluate if the correct source frame is being recorded at the first frame of the edit. If this is incorrect, adjust the gfx value, save the file and re-try the layoff. Next try adjusting the audio value to sync with the video. By repeating this procedure, you are able to walk in the frame accuracy for that particular deck type.

The Timecode Generator parameters are only used for a PLAYOUT-Assemble to adjust the timing of communications of timecode changes to the VTR. 

Tip: Only adjust one parameter at a time. Adjust the video until it is correct and then move on to the gfx and audio respectively.


If you are unable to establish deck control, please check the following possible causes.

First, check any physical connections to ensure all cables are securely connected to the proper ports / device. Ensure you are using valid (COM) cables for the connections. A standard 9 pin connector, like those used for deck control, can be wired many different ways. Your cables should follow the standard RS-232/RS-422 pin out.

Check that the deck has been properly configured for remote control. Consult the user manual for your particular deck, and more information.

Check that the PConfig.xml file has been edited properly. Revert to a backup copy, and start over if necessary.

If you are using an RS-232 to RS-422 converter that draws power from the COM port, you need to switch the value of the drsrts from 0 to 1 in the initial vcr configuration line.

If you are still experiencing problems with controlling a deck, contact ASSIMILATE Technical Support.



The text above the Playout controls shows the SDI output signal and the type of VTR currently connected. If a four-digit value is shown, then the current deck has not been fully configured. 


The timecode displayed above the Playout controls shows the current timecode being read from the connected VTR.


The Connect button is used to establish communications with the VTR. Pressing the Connect button sends standard connection information through the serial control cable and awaits a proper response from the deck. If no response is received, the PLAYOUT controls are not activated.


The Record button starts the record to tape. The deck is pre-rolled, and then a record is executed. The state of the Insert and Assemble buttons determines what type of recording is performed.


The In Numerical Slate determines the starting timecode for the record operation. This timecode is relative to the starting timecode of the Construct. For example, if the Construct’s record timecode, set in the Construct Settings menu, is set to 01:00:00:00 and a value of 01:01:00:00 is entered into the In slate for the PLAYOUT, the recording will start at 01:01:00:00 on the tape, with the frame at 01:01:00:00 in the Construct. You do not have to set a separate In point for the Construct and the VTR. They are assumed to always be identical.


When Insert is activated, Playout performs an INSERT EDIT to the VTR. Insert edits are frame accurate edits that begin and end with clean edits. This means timecode and control track are not broken as part of the edit. This requires the tape to already have valid control track and timecode for the edit to be performed.


When Assemble is activated, Playout performs an ASSEMBLE EDIT to the VTR. Assemble edits start with a clean edit, but the end of the edit breaks any control track on the VTR. Assemble edits do not require the entire tape to be per-striped with control track and timecode. These signals are regenerated by the VTR as part of the record process. However, if the tape does have per-striped control track, the out point of the ASSEMBLE EDIT breaks the continuity of this control track.

Note: Be sure your VTR is set up correctly to regenerate proper timecode for the format you are recording onto.

Tip: You can DE-activate both INSERT and ASSEMBLE to preview the edit without actually performing a RECORD operation to the tape.


Enabling this option will disables cueing the VTR to a specific point and instead starts recording right after obtaining a servo-lock.


When Assemble is set, you can select the timecode that is to be send to the VTR. Either the Construct / timeline timecode (Rec-TC) is send or the source timecodes of the individual shots (TC) is passed along.


When Audio is available and enabled in the Player, you can activate the audio channel on the VTR.


Rewind the VTR towards the beginning of the tape

Go back 1 frame on the VTR

Put the VTR in Play Mode

Go forward 1 frame on the VTR

Fast-Forward the VTR towards the end of the tape


Cue the VTR to the timecode indicated in the TO Numerical Slate


The TO Numerical Slate allows you to input a timecode for the CUE command. When the Cue button is pressed, the deck cues to this timecode value.


In the Configuration dialog you can set the Playout to Emulate-mode. This mode makes Playout available but without the VTR control. When pressing Record in Emulate-mode, a normal Playout run is performed but without actually activating the VTR. This mode can be used for testing, reviews or e.g. audio sync on SDI. Note that also clicking the Connect button while holding down the Quick key: Ctrl will switch the PLAYOUT module in Emulate-mode.


SCRATCH uses the NVIDIA drivers to embed Ancillary metadata (ANC) in the SDI signal. This option is enabled by default. To switch it off you need to set the Advanced Preferences variable SDI: Disable ANC Support. There are four ancillary data tracks available for adding timecode data - VIDC, LTC, Film Timecode and Production Timecode. By default SCRATCH embeds the timeline timecode to VITC, the shot timecode to LTC and replicates both timecode in the Film- and Production tracks. You can change which timecode is assigned to which track by switching the Regenerate option on the Playout menu panel from Rec-TC to TC.


Latest SDI cards support embedding audio in the SDI signal. As was discussed in Chapter 5 - The Player, you have a separate set of audio settings for Playout. Selecting the SDI Embedded device will include the audio played in the SDI signal available for recording by the VTR.  

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Last Modified:Friday, June 29, 2018