The exception being possibly some japanese models mentioned earlier in the thread. One distinction between the software decoder and most VCRs is that the TBC happens before the color upconversion in the software one, while in a VCR, that's usually one of the last things that happens to the video signal. PLLs are a common thing in electronics, but I haven't found a ton of info on it in the digital domain, especially not for video. The PLL adjusts the frequency that is mixed with the frequency-off tape which cancels out jitter. The way a VCR does this, and what I'm hoping to get working is use a phase-locked loop to regulate the signal used to upconvert the chroma to the normal frequency. Wobble isn't adjusted evenly over the whole line, and since the colour hue depends on phase of the color signal, the resizing may be messing with it a bit. I suspect this is what's causing the "stretched" chroma we get currently. It doesn't seem to be enough to correct for wobble in the chroma signal though. It finds the start of the line using the hsync pulse and resizes the line. The TBC-part of the code aligns the lines of a field up the horizontal synchromization so you get a straight image. The thing I'm a bit stuck on with the chroma part is Automatic Frequency Compensation of the chroma signal. I'm not really at the stage of fine-tuning the saturation levels anyhow so having accurate samples is not all that important. Are you not able to use my current samples and I would need to re-record them? That's fine, but it will take me some more time to re-record the correct shades.
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