Working with DJ style pitched TC

Pitched LTC Time code

There are use cases in which time code needs to be pitched in a greater range than a usual broadcast environment would experience. This includes working with synced audio coming from a DJ booth. To cater for this, we have extended the LTC time code settings in the drift correction drop down.

Pitched Time code in UI

The most important settings are available in the UI of PIXERA. The “Adaptive Drift Correction” can be found in the SMPTE Settings in the Inspector of a Timeline.

1. Select your timeline
2. navigate to your timeline inspector
3. navigate to your SMPTE settings
4. set Mode to receive 
5. set Drift Correction to Adaptive (Beta)

Parameters in Timeline inspector:

Drift Correction:

None: The timeline will be initially triggered upon TC, no drift correction will be applied during runtime.

Standard: PIXERA's default drift correction behavior.

Adaptive (Beta): new drift correction featuring a broader drift range

Correction Rate:

Set at 3 by default. This is the frequency (in Hz) at which the controller updates its correction. A higher rate means faster responsiveness. 
The maximum setting should not exceed 7! Please use carefully!
Currently, only LTC via audio can correctly implement values larger than 1. So when using the mechanism with other forms of time code input this should be set to 1 (correction will still be applied but will tend to be less effective than if the rate is correctly set to match the capabilities of the input device).

Speed Smoothing:

Set at 10% by default. Filter factor applied to the computed speed to avoid abrupt changes. Higher values favor smoother but slower responses.

Tweak Config

Besides the parameters that are offered in the GUI, there is an extended parameter set that is hidden underneath. If you need further refinement of the pitched TC behaviour, you will need to place a tweak_config.json into the following directory in the main/director PIXERA server:  

C:\ProgramData\AV Stumpfl\Pixera

Please note: ProgramData is a hidden folder

tweak_config.json

Once you have placed the tweak_config.json into the directory, you must restart PIXERA in order to initiate the settings.

Changing the settings

To change the settings, open the tweak_config.json in Notepad, Notepad++ or any other suitable editor. Change settings as needed, store the file. Restart Pixera to initiate the new setting.
 

These are the parameters insidethe tweak_config.json:

"smpteTimecodeInputPitching":
 {
	"isActive": true,
	"rate": 3,
	"positionSensitivity": 0.4,
	"speedSensitivity": 0.8,
	"speedSmoothing": 0.3,
	"maxSpeed": 20.0,
	"atSafetyFactor": 0.5
 }

isActive:

Enables or disables the PD controller mechanism. When false (or if no config is present at all) the original, completely unchanged drift correction code is used.

rate:

Frequency (in Hz) at which the controller updates its correction. A higher rate means quicker responsiveness. Currently, only LTC via audio can correctly implement values larget than 1. So when using the mechanism with other forms of timecode input this should be set to 1 (correction will still be applied but will tend to be less effective than if the rate is correctly set to match the capabilities of the input device).

positionSensitivity:

Proportional gain. Determines how strongly the difference between target and current position affects the speed correction. Higher values mean faster convergence but risk overshoot. Corresponds to kP in the standard PD controller model.
ATTENTION: setting above 0.9 may result in overshoot

speedSensitivity:

Derivative gain. Determines how strongly the difference between target and current speed affects corrections. Helps dampen oscillations. Corresponds to kD in the standard PD controller model.
ATTENTION: setting above > 0.9 may result in overshoot

speedSmoothing:

Low-pass filter factor (0–1) applied to the computed speed to avoid abrupt changes. Higher values favour smoother but slower responses.

maxSpeed:

Caps the maximum playback speed to prevent unrealistic or destabilizing speed adjustments.

atSafetyFactor:

Fraction of the inter-update interval used to project time slightly into the future. This helps ensure that threads besides the update thread that access the timeline state do not see non-monotonic or outdated values due to timing jitter.

PIXERA 26.1 INTER 31  | 03. March 2026 | OK./BC