Sync problems during analog capture?

[BusterD]

On a related note, I discovered a while ago that when backing up Laserdiscs (ones that have a digital track) using my Japanese Blu-ray recorder, the recorded audio lags behind the same audio recorded digitally using a PC. It's not too bad, like 15-20ms every 30 minutes, and much less than when recording analog audio using a PC. Haven't noticed any dropped frames or anything in the video, so I guess it's because the recorder is recording from the Laserdisc player's analog outputs, and has a slightly different clock when converting back to digital. Still kind of annoying though.

[pipefan413]

I'm still not really sure how best to handle this issue and I'm not sure how others are unless you're just cutting into the audio to remove or loop samples to fix sync as the recordings lose sync with one another. I can simultaneously capture analogue video with 20-bit 48 kHz analogue audio, PCM audio (bit perfect), but the 96 kHz audio drifts significantly ahead of the 48 kHz version and the PCM so I don't trust it at all. It does seem to have a noticeably lower noise floor though, which is frustrating because it probably makes it more useful to actually use.

Is there a way of automatically aligning two captures of the same audio in software (e.g. REAPER, RX) that adjusts the rate but keeps the pitch the same? I can adjust speed but not pitch in RX but it's a very manual process so it'd be a *lot* of trial and error to get it right.

The other reason I'm wondering about this is for fixing the speed-up of time-compressed NTSC LaserDiscs, although for those I *will* need to also adjust the pitch. Again, that can be done in RX but since I don't know the amount of speed-up it's extremely tedious. For things like THE EXORCIST, I'd like to record the whole time-compressed LD with the 96 kHz card then resample it to the right speed and pitch without too much guesswork having to happen.

[BusterD]

Still need to check to see if the captures from the ESI X86 I just got also has this audio drift. But yeah, I've just been cutting audio every 5-10 minutes since the drift isn't noticeable then. My OCD would rather have this slight drift than resampled audio

[BusterD]

Looks like the ESI U86 XT is slightly more accurate (at least when compared to the audio/video captured by my Blu-ray recorder) than the M-audio, its drift is only about 100ms per hour for a 2496 PCM capture (haven't tested other bit-depths/sampling rates). But it drifts BEHIND the BD recorder audio instead of ahead like the M-audio, so I unless I stretch/resample the whole file, I have to add in a small amount of ms every 5-10 minutes or so. I do this by stretching mostly silent spots, so it's a bit more of PITA than cutting a few ms of silence.