TBT: Time Base Torture
How good is your time-base corrector, really?
Tired of the mysticism ? Want to check a TBC before purchase?

TBT is an open-source test rig (SW/HW) that tries to answer that with measurements instead of eyeballing a monitor.
An ESP32 (about $5) generates NTSC composite video with precisely controlled faults that can then be captured and graded with an SDO.

It covers the problems a VHS or Betamax deck throws at a TBC:
- line jitter and wow and flutter
- head-switch skew
- dropped and lost fields
- snow and noise bars
- weak burst
- hum

Each fault comes in a ladder from mild to brutal. The signal goes through the TBC under test, and a USB scope captures what comes out. TBT then reports exactly what the TBC fixed, what it passed through, and where it broke.
A full field trial runs about 70 tests in roughly seven minutes and produces an HTML report with a provisional grade out of 100.

Highlights
About 30 tests, about 70 rungs. Going from “how peculiar to “Good God man!). Timing, sync and structure, colour and burst, levels and noise, plus fault tests: how many lost fields in a row a TBC rides through, and a stress-and-recovery hunt for units known to be buggy like black AVTs.

Frame markers in the picture. Every field carries a coded marker. TBT tracks each frame through the TBC and catches dropped, repeated, torn and ghosted frames. Looking for the failure modes that TBCs are known to exibit when dying, or have Chipset defects

Measures the Analog Signal, not just the constructed picture.  When using channel 2 can provide Jitter reporting, and validate what (if anything) the TBC is doing to the signal.

Dying Unit identification . A dropout watch samples the output every second for minutes at a time, allowing for long burn in runs, that can point to failng caps, heat dissipation issues…

Repeatable and comparable. Every fault is deterministic and described in a manifest. Run trials side by side to compare units, or the same unit over time. Saved trials can be re-graded later.

Works with what you have. So long as that’s an ADP2230
Two scope channels give the full picture of TBC performance
With --channels 1, a single channel and a single cable still work..but latency and jitter are going to be based on the model, not the signal.

Find it here: https://github.com/jordancrombie/TBT. The README covers wiring, commands and a sample report. The test catalog is in docs/design.md.

The software was made with the help of AI (100% AI Slop!)
The meat puppet (me) bought the gear, wired it, helped design the test cases.

Also, use the test software at your own discretion. It’s been validated against Datavideo TBC-1000, AVT-8710s all without issue…but it’s in the name…it will put the components under stress.

*Edited to highlight the sloppiness of AI that helped build this!

Has anyone found a good solution for switching cameras on a constellation using DMX? doing a show on disguise at the moment and using an ma3 light for control with companion to switch cameras. Looking for a solution to run everything off of the console just to reduce setup time. I have a mini PC in my disguise rack and was considering building a patch in something like Châtaigne but open to any alternative suggestions!

Thx

Hello all,

I'm currently trying to get Companion button to send a Custom Vendor Request (CVR) to the Multi-RTMP plugin in OBS, but nothing happens when testing the button. I do have OBS main stream live and a the connection status is good between Companion and OBS. I am probably missing something or not understanding. I would like your help as soon as possible if you have this figured out.

Here is the link to the plugin: GitHub - davidcool/obs-multi-rtmp-websocket-support at pr-obs-websocket · GitHub

I have already tried entering the information correctly as shown in the GitHub page, but with no positive results.

Desperately in need of at least 1 UIC for the FSN1400 chassis, who can help me out? Please DM me.