SonyEPM: Capture Tape Question

bakerbud9 wrote on 4/3/2004, 3:44 PM
Sony,
When using the capture tape feature, is it possible there will there be dropped frames at the ends/beginnings of the separate AVI files that are created, assuming the software detects discontinuous timecode? Or is it that the capture software can close an AVI file and create a new one within 1/30 of a second to guarantee that no frames will be missing?
This is assuming that there are no "gaps" in the timecode anywhere on the tape, but that different scenes may contain timecode that is not chronological with that of a previous scene (which I assume is how the software detects scenes).
Sincerely,
Nate

Comments

PeterWright wrote on 4/3/2004, 5:06 PM
It's not discontinuous time code (which is to be avoided always) that Vegas uses to detect scenes, but discontinous TIME, as recorded by the camera's time/date setting.

If any frames are dropped, Vegas reports this straightaway - if you want, you can set it to stop capture when this happens. You should not normally expect to drop any frames, but this may happen IF there is a break in timecode, but then the dropped frames will normally represent the piece of unrecorded black in the break.

To avoid breaks in time code, always allow the camera to run for a couple of seconds after a shot, and make sure that the next shot begins before the previous time code ends. If you don't rewind or remove the tape from the camera, this will happen automatically, but if you do rewind/remove, pause the tape during the 2 seconds "overrun".
jetdv wrote on 4/3/2004, 5:54 PM
(which I assume is how the software detects scenes)

You assume incorrectly. Scenes are determined based on jumps in the Date/Time code. That's why it won't work if you don't set the clock in your camera.
bakerbud9 wrote on 4/4/2004, 7:55 PM
so how likely is it that frames can be dropped when capturing such a tape to multiple files? if frames are dropped, how can i know?
-nate
PeterWright wrote on 4/4/2004, 8:06 PM
If you have a well set up system, it is not likely that dropped frames will occur.

As I said, Vegas Reports that there are dropped frames - and there's a counter which shows during capture. If you watch this, and it goes up during a break in time code, you know there's no problem. It won't normally drop frames just because it's starting a new media clip.

Rather than worry about likelihood - have a go and see if frames are actually dropped - you may be worrying over something that isn't going to happen.
bakerbud9 wrote on 4/5/2004, 8:22 PM
hi peter,
ok. thanks. the reason i'm worrying is i've been given over 600 video clips that comprise a 2hr documentary captured from a single tape but with the "detect scenes" option on while capturing (and thus the 600 clips).

when i put the 600 clips on the timeline and play, for the most part it sceems fine. but there are an occasional "glitch". however, its possible the glitches are because the clips are on an external usb hd. but i worry they might be dropped frames from the capture process.

since i didn't capture the project, i don't know wether vegas reported dropped frames during capture or not.

i'm debating if i should just bite the bullet and recapture the whole documentary all over again... even though this means having to rent a dvcam vtr. i basically just need to encode the whole thing into mpeg so i can burn it in dvda.

-nate
PeterWright wrote on 4/5/2004, 8:48 PM
Something I'd love Vegas to have is a "Clip Properties/Data Rate" facility, like the one in Premiere, where you can analyse any clip, SEE on a graph whether it has dropped frames or not, and know exactly when they occur.

There may be a separate app. that does this - can anyone help?
bakerbud9 wrote on 4/6/2004, 7:54 PM
well i recaptured the project today.... i just didn't want to take the risk. even though its a minor pain to go rent a dvcam vtr, the effort and time is much less than rendering that whole project and burning to dvd only to find out some of the glitches are still there (and then having to rent a dvcam and recapture anyways).

so perhaps this remains a good "educational question" for all of us; even though my immediate "fire" has been extinguished. =)
-nate