HDV video capture and scene detection

Tech Diver wrote on 10/1/2009, 9:28 AM

For many years I have been working only in SD format and have not had any capture issues. Yesterday for the first time, I did a video capture in HD format using the application built into Vegas. All went well except that every clip has an extra THREE frames from the NEXT scene and is missing the first FOUR frames from the CURRENT one. To further complicate matters, there is also a frame missing that prevents me from reconstructing the flow by combining the two clips. This is not a terribly critical issue; just a pain in the butt that really bugs me. By the way, I know that the frames are correctly recorded on the tape because if I use the camera's internal down-res to output in SD format into Vidcap60, all is fine.

Has anyone seen this before and can it be corrected?

Here is some relevant information:
Camera - Sony HVR-A1U
Connection - 1394a
Software - Vegas 7.0e
OS - Vista 64
HW - i7 950 + 6 GB

Note that my capture RAM buffer size is set for 75%.

Peter

Comments

johnmeyer wrote on 10/1/2009, 10:01 AM

Capture has always been a problem in Vegas. For DV, you can get Scenalyzer and work around the weak capture in Vegas. For HDV, some people use HDV Split, but it is not clear to me whether this creates a "flavor" of HDV that edits more slowly (because the MainConcept decoder gets used rather than the Sony MTS decoder).

So, the only solution I've found is to turn off scene detection and do without it. Even with that, and even with the RAM buffer suggestion a few days ago, Vegas still insists on randomly creating new scenes from time to time and skipping random frames. I capture from a Sony FX1. You can usually re-capture the portion where the scene split happens in order to recover the missing frames. For live captures (where I capture directly to the laptop) I always capture to tape as well and, when needed, go back and re-capture around the glitches.

I have this problem on ALL computers to which I capture HDV, and with many different cables, and with many different versions of XP. Many other people have reported the same problems

Tech Diver wrote on 10/1/2009, 10:16 AM

John, thanks for the rapid response. I'll play around with DVD Split and see if I can use it as a substitute. I helps to know that I am not alone (I guess misery loves company).

Peter

johnmeyer wrote on 10/1/2009, 12:19 PM

It's actually HDVSplit:

HDVSplit

It has never been updated, and is pretty crude, but a lot of people in this forum like it. I've never used it (because it used to create HDV files that Vegas insisted on playing with the MainConcept playback codec, which meant they played back at less than full frame rate). That may no longer be a problem with never versions of Vegas.

Christian de Godzinsky wrote on 10/1/2009, 12:23 PM

Hi,

This is not a problem for Vegas - its a problem for us users. Vegas HD scene detection has been broken since day one!!! As I remember it was already broken in 7, not fixed in 8, neitherhas it been fixed in 9.0b (be it 32 or 64 bit).

This is even a recognized problem by SCS. Nothing has been done to fix it during these years - and that is totally unacceptable. How come a "pro" application cannot handle a elementary task! There ARE other applications that can do it correctl,y as mentioned. So there IS a workaround.

It is not an excuse that HDV is a complicated format with temporal compression. Yes - it migh be complicated to write working code, but not impossible, and its a pity that SCS has not done anything to fix this. It seems that SCS just has decided not to fix this - ever. Probably they are waiting that we all soon switch to HD-based recording and think its unnecessary work. WRONG. I have tons of HDV project still to come, and this "issue" bothers me every time. Most of the recordings are short scenes of 5 seconds each, that are recorded in such a fashion that they must be reordered on the timeline. So - either I have to capture everything as one long take, and manually split 600 about takes. OR - then I let the scene detection do the work so the scenes are splitted during capture so its easy just to move them around. But this means that I have to edit each clips end. A tedious work in any case.

I have lost my faith in that SCS will ever fix this. It would have been fixed already if it would have been on a to-do list...

So - I am forced to use also other sw for the capture, since this pro application cannot perform this basic task properly. Sorry if I sound a little bitter, but that is how I feel when I see new people again and again stumbling into this unfixed problem...

Christian