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-   -   Strange problems capturing from SR-V101 with PVR-250 (https://www.digitalfaq.com/forum/video-capture/3652-strange-problems-capturing.html)

Bilge 11-11-2011 03:35 PM

Strange problems capturing from SR-V101 with PVR-250
 
3 Attachment(s)
I've been doing some capturing with my JVC SR-101US, but I'm getting some strange effects in the videos.

Does anyone know what is wrong? I've tried 2 different s-video cables and a composite and I still have the same problem.

kpmedia 11-11-2011 04:11 PM

I'm not seeing anything unusual.

There is some very minor image latency in the videos, but that's a side effect of several areas:
  • Noise reduction - Temporal NR parameters, to be specific
  • MPEG encoding - The nature of GOPs, 4:2:0 chroma compression, and video compression in general

Watching it as a video, not frame by frame, I don't see anything odd.

Bilge 11-11-2011 04:24 PM

2 Attachment(s)
I've added another image, 11 is mine and 12 is someone else's capture from the same video.

You should be able to see it now, it's like motion blur.

kpmedia 11-11-2011 04:30 PM

That doesn't really mean much. The tape itself could be defective -- I just finish handling a tape like that. Many 1980s video cameras had problems with ghosting images at record time, and that can happen with VCRs, too -- including the professional decks used to dub tapes (which can be transferred to copies made during the creation of distribution duplicates).

The only way to fairly compare it is to use the same tape in both workflows.

You can always try turning off all of the VCR's filters (EDIT mode, no TBC), but then that somewhat defeats the purpose of the VCR. In all likelihood the VCR is fixing a bad tape, so it's doing its job.

You'd also need to capture as an uncompressed or lossless AVI -- not MPEG. Or I-frame MPEG, and at a high bitrate.

Bilge 11-11-2011 04:36 PM

I only gave one example, it has this weird effect on every video tape I've tried.

I used that example because I had something to compare it with.

I have a PVR-250 and I thought the best way to capture with this card is with WinTV which saves the files as MPEG.

kpmedia 11-11-2011 04:40 PM

This is one of those problems that's impossible to diagnose remotely.
The VCR may be defective.
The capture card may be defective.

The Hauppauge PVR-250 is an MPEG hardware card, and it's made for capturing MPEG files with WinTV.
You'd have to compare it to another video card entirely.

Or another VCR.

NJRoadfan 11-11-2011 04:40 PM

I have seen that chroma ghosting before. It was present on this demo Video-8 tape that came with my camcorder (towards the end in the commercial for the camera).

http://www.youtube.com/watch?v=lqMsR6K9Syc

Going frame by frame you can see a chroma "ghost" from the previous frame. I thought it was my hardware, but its actually the tape itself. I capture uncompressed, so it isn't MPEG artifacts.

Bilge 11-11-2011 04:52 PM

I didn't notice this problem when I captured using my PAL VCR, so it must be the JVC that's defective :(

jmac698 11-11-2011 05:36 PM

1 Attachment(s)
Come on guys, those are blended frames. I made a script for a problem like this, it was due to my capture settings. Btw, you should record to uncompressed AVI. I have a PVR as well, and yes there is a way to capture raw.
http://forum.doom9.org/showthread.php?t=158230

Btw, Virtualdub will show the image in Preview but offers no way to capture from the Preview pin. I even asked the author to add this feature so we could easily record from PVR cards in Virtualdub, but he refused.
http://forums.virtualdub.org/index.p...T&f=6&t=19558&

I can probably fix your video however it would just be easier to recapture as AVI. First step is to downlaod graphedit.
http://www.videohelp.com/tools/GraphEdit

Then it's almost like a drawing program, you add boxes and draw lines between them. Quite simple, except knowing where to find the boxes in a big list. It would be even easier if I had the resulting .grf file but I don't have one saved.

lordsmurf 11-11-2011 05:46 PM

It's not blended frames, as only the chroma channel is blending. A blended frame blends the luma, too. This is an issue with temporal noise reduction, and that can be faulty circuity in a VCR or capture card.

But it can also be a bad signal on the tape.

AVI vs MPEG recording is really an issue of preference, dictated by needs and wants. I've gone over this before, but the capture guides are getting expansions right now.

jmac698 11-11-2011 06:15 PM

Bad choice of terms - yes it's chroma only. I examined it further and it's ghosting over about 3 frames. However it decays quickly so I should be able to fix it.

Check for any type of chroma noise reduction features being on and turn them off. I'll see if I can fix it though.

My particular capture issue, was an issue with recording in YV12.
The pulldown pattern creates 3 progressive followed by 2 interlaced frames. Those interlaced frames contain chroma from two different film frames on every other line. If you record those interlaced frames in YV12, the chroma gets blended. Therefore the sign of the problem is blended chroma on two frames. MPEG2 is supposed to blend the lines of chroma per field, so this isn't normally on issue. I think I had checked some setting to record in YV12 as a capture setting, in which case a driver blended the chroma in the wrong way, taking the chroma from the whole frame as if it were progressive.

Anyhow it can be perfectly recontructed due to redundant information in pulldown.

It's hard to see if this problem is only on select phases of the cadence or in general. It would help if I had a capture of a brightly colored object moving horizontally.

jmac698 11-11-2011 08:25 PM

I'm getting a strange pulldown pattern, it's about 16 frames/sec, how am I getting that?
Step through the first 30 frames, is this what you see?
0 clean 0
1 clean 0
2 clean 0
3 clean 0
4 clean 1a
5 clean 1b
6 clean 2a
7 clean 2b
8 clean 3
9 laced 3/4
10 clean 4
11 laced 4/5
12 clean 5
13 laced 5/6
14 clean 6
15 laced 6/7
16 clean 7
17 clean 8
18 clean 8
19 clean 9
20 clean 9
21 clean 10
22 clean 10
23 clean 11
24 laced 11/12
25 clean 12
26 laced 12/13
27 clean 13
28 clean 13
29 clean 13
30 laced 13/14

jmac698 11-11-2011 08:33 PM

There's a way of looking at this that gives me 25fps, it looks like PAL->NTSC.
What standard is the tape? What standard(s) are the VCR?

lordsmurf 11-11-2011 08:39 PM

I was just about to say something similar.
Based on IP address (which Site Staff can see), Bilge is in UK, so NTSC is not a native format.

I'm almost wondering if this is an SR-V10U or an SR-V10E --- U is NTSC, E is PAL.
The PAL VCR would play NTSC as quasi-NTSC, PAL-60, and would account for this ghosting of the image.

Please verify.

Edit:
Re-reading, this is actually an SR-V101US, the revision of the SR-V10U (same VCR, more or less, but in uglier case).
But verify anyway, just to appease my curiosity.

This could also be power-related ... maybe. (I've seen stranger.)

NJRoadfan 11-11-2011 11:05 PM

In the case of my tape, it was played back on a Sony CCD-TRV65 Hi-8 HandyCam with its built in TBC and DNR functions on. It was captured uncompressed YUY2 4:2:2. The source is definitely native 29.97fps with no pulldown. The chroma ghosting only lasted 1 frame and only on that segment of the tape (I went through most of the video and checked parts with abrupt scene changes). I quickly checked my other captures (both VHS and Video-8) and I haven't seen it, so its on that particular tape.

jmac698 11-11-2011 11:39 PM

Must have been an editing issue. Haven't looked at it yet.

Bilge 11-12-2011 02:01 AM

Wow thanks for all the help guys, I do indeed live in the UK. I imported the SR-V101US & I have bought NTSC tapes over the years.

I was wondering if it could be a power problem because I have to use a stepdown voltage converter.


I'll try and capture some more clips later today.

jmac698 11-12-2011 11:40 AM

Do you have an NTSC dvd/bluray/media box?

Bilge 11-12-2011 01:15 PM

Unfortunately no :( does anyone know of a good voltage converter that I could use?

lordsmurf 11-12-2011 01:22 PM

I'm not 100% positive that this is a voltage conversion error -- but I have seen similar problems when using a 240V stepdown convert for making a PAL VCR work on North American 120V power standards (NTSC video area).

For me, ultimately it was unnecessary, as the specific VCR (JVC HR-S7965EK) has a worldwide power adapter inside the unit (110V-240V ~ 50Hz-60Hz). I didn't know this was the case until diagnosing the VCR playback quality problems, at which time I discovered the power rating. I just use a plug shape adapter these days. The power converter was just a wasted purchase of $15. Unfortunately, I don't think this will be an option for you.

Look for a non-cheap quality converter. I don't have any immediate advice on where to buy one in UK.


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