Game consoles/TV-Out: 59.94i or 60i?

[zilog jones]

Does anyone know if NTSC/PAL60 video game consoles and PC TV-outs actually output 59.94Hz or 60Hz? I know arcade games often output slightly non-standard (well non-standard compared to NTSC) frequencies like 60Hz and 60.606Hz, but can't seem to find much info on games consoles or TV-outs from PC graphics cards, and I don't have an oscilloscope -_-

If I capture a 30fps source at 29.97fps, will I get dropped frames, tearing, audio sync issues or anything else weird?

[Meat_PoPsiclez]

Capturing at the wrong fps (even slightly) *can* cause some dropped frames, but would likely be ~2 frames per minute, or less depending on the flexibility of the capture card.
AFAIK all modern consoles (snes+) are spot on specification, older consoles such as NES and Atari might not be so accurate, especially considering the very simple timing circuitry they used. If one were so inclined you could check your device with an oscilloscope, and look for the vertical blanking periods. You could determine the exact vertical refresh rate that way. This might be easiest to achieve with a digital scope, as many include good frequency counters.

[zilog jones]

Cool, thanks for the help. Maybe I'll bring my NES into one of the electronics labs in college some day and measure it there :D

[Arachnotron]

As far as I understand the PAL-60 process, the NTSC timing is left intact and only the chroma is shifted to a higher carrier frequency and PAL encoded. Which would argue for the timing being 59.94. But there are always exceptions I suppose :)

Since capture devices have to be able to deal with small variations anyway (tape, broadcast) and are driven by the synchronisation pulses within the videostream I don't think the difference would matter much even if it was 60 fps.

[scharfis_brain]

but the container one is capturing into (AVI) doesn't support VFR, meaning it is fixed to a given value and cannot adapt to the inputted signals.

So it will cause drops / dupes.

[Arachnotron]

but the container one is capturing into (AVI) doesn't support VFR, meaning it is fixed to a given value and cannot adapt to the inputted signals.

So it will cause drops / dupes.But the container does not have to support VFR. As long as the capturing process can handle small variations, what does it matter that the resulting AVI will be played back later on with a fixed framerate?

Some of your avisynth scripts are very << 25 fps too, and you can still save the result in an 25 fps avi :D