What do is this video issue called?

[Derrydavis]

Hi,
I'm getting partial frame overlays randomly at the bottom of the screen while video capturing and not sure what to even call it so I can start researching. Is there a name for it that will help me find the root cause / fix? Attaching an image for an example.
Thanks so much in advance, appreciate any help.

[Attachment 69422 - Click to enlarge]

[dellsam34]

Without a sample video and what capture hardware and software and format you are working with, no one will be able to help.

[Derrydavis]

Hi!
Capture hardware is Roxio Video Capture USB (directshow)
Software is VirtualDub 1.104
Format is VHS. Capturing to avi through a VCR.
https://youtu.be/ppujsjZixHk

.... Ok, this is strange, it isn't happening on the video after uploading to youtube. Here's a link to the source file

And apologies for the bad grammar on the title, still 1/2 asleep.
Thanks again

[dellsam34]

It could be VDub display problem. Not sure why your sample is RGB and 640x480, It should be YUV 720x480.

[lollo]

The odd field is corrupt. It can be a glitch in the tape (even because there are 2 "inserted" frames before the corrupt one) or the VCR .



If occurring rarely, it's easily fixable in post-processing with a frame interpolation.

The defect is also present in the yt video, but it is mitigated by the mp4 compression (and by deinterlacing?) and spread to both fields:



Definetely your capture should be lossless 720x480 YUV.

[DB83]

+1

Go back to your tape. Install a lossless codec such as huffyuv or lagarith and capture native @ 720*480 (ie no output alteration)


If the issue persists then report back.

[Derrydavis]

No luck. Hopefully I followed the instructions correctly. I installed the huffyuv and captured at 720*480 (I think)
https://files.videohelp.com/u/305044/retest.avi

[Derrydavis]

Also, for reference, I've tried 2 different VCRs. Checking other tapes to see if it happens there too.

[DB83]

You might have installed the codec but you have not selected it from the compression settings. You video has not changed codec (or lack thereof) from before.

[Sharc]

If nothing helps, try something like

AVISource("retest.avi")
ConvertToYV12(interlaced=true)
AssumeTFF()
QTGMC().SelectEven() #keep the good fields only

You will loose 50% of the temporal resolution though, and introduce jerkiness where the fields are corrupt or missing.

The capture has all kind of defects though (glitches, dropped fields or frames, parity flips ....)
So yes, first is to revisit your capture setup, and capture to YUV (YUY2) rather than RGB. Otherwise garbage in - garbage out.

[Alwyn]

@Derry, the conventional wisdom is to use VDub 1.9.11 for capture. You can get it from here:

http://www.digitalfaq.com/forum/video-conversion/1727-virtualdub-filters-pre.html

Video>Compression:

[Attachment 69447 - Click to enlarge]

Video>Capture PIN (assuming you're on NTSC_M):

[Attachment 69448 - Click to enlarge]

[lollo]

In addition to what Sharc properly said, your capture suffers of halos; try to reduce/remove the sharpening in the VCR or in the Capture Card.

You also need a lineTBC correction to have verticale lines straight and not like they are. Upgrade to a better VCR with lineTBC or add a specific DVD-R Recorder in pass-through mode.

[Derrydavis]

I think I have it capturing Huffyuv 2.1.1 but stuck on the resolution of 640 X 480. Not sure where to set for 720 X 480.
I'm also using VDub 1.10, is 1.9 the preferred version?
Thank you all for the info, a lot to absorb after being away from video capturing a long time (and not really knowing it that well when I first worked on it years ago).


[Attachment 69459 - Click to enlarge]

[DB83]

If I recall correctly, 1.10 was an experimental/non-official (as far as the original author was) version.

1.9 is an 'official' version.


But if vdub gives you grief with it's settings - and there are many - then amarectv is a simplier program to use. Even so, 640*480 should only be set from the output resolution - I hardly see roxio setting that as default since it is not for a analog to digital.


But if you want to continue with vdub I can provide the settings (although my capture device is different). Not right now tho.

[Alwyn]

stuck on the resolution of 640 X 480

The resolution is set on the Video>Capture Pin screen. There's a dropdown menu for it called "Output size".

What is available varies, depending on the capture card, but you should have a 720x480 option for NTSC.

Also, try Video>Custom Format (down the bottom). You can set the frame size there.

[Alwyn]

640*480 should only be set from the output resolution

You'll need to clarify that because, unless I am mistaken, the output SIZE is to be set to 720x480, as I show in my image above.

[jagabo]

You need to get your capture process fixed. The problems in your video (duplicate frames, dropped frames, and torn frames) have two main causes: time base errors in the source signal, and CPU and disk speed errors on the computer.

Time base errors can often be fixed using a DVD with line TBC on its passthrough (US$100+). If that's not enough you may need a full frame TBC (US$1000+).

Computer speed errors are generally fixed by using a fast lossless codec during capture (this reduces the disk data rate requirement, a common problem) and saving the audio as uncompressed PCM (don't waste CPU time compressing the audio). During capture a new frame arrives from the capture device every 1/30 second. If the computer busy when that new frame arrives it may be missed, causing a "dropped" frame, or the previous frame may be written again causing a duplicate frame. So avoid any other video or audio processing during capture. Do those thing later when timing isn't critical. Whenever possible capture to a drive that's not your boot drive. Windows is creating, deleting, and modifying log (and other) files on the boot drive all the time -- that will interfere with your capture.

In a worst case scenario (ie when it's impossible to get a clean cap) your sample video could be fixed in AviSynth. But it can be a lot of work and results won't be perfect. See attachment, original video on left, fixed on right.

[Sharc]

Computer speed errors are generally fixed by using a fast lossless codec during capture (this reduces the disk data rate requirement, a common problem) ......

Capturing to YUV (YUY2) instead of RGB as in the OP's retest.avi should reduce the disk data transfer rate significantly, I think.

[jagabo]

Computer speed errors are generally fixed by using a fast lossless codec during capture (this reduces the disk data rate requirement, a common problem) ......

Capturing to YUV (YUY2) instead of RGB as in the OP's retest.avi should reduce the disk data transfer rate significantly, I think.

Yes, it's 2/3 as much data closer to what's in the analog signal. Converting to RGB on-the-fly wastes CPU time risks losing the super-blacks and super-whites.

[Derrydavis]

I'm thinking it's a hardware / source issue. I see it happening when I simply preview the video, no capturing happening. Trying some different capturing hardware later today / this week. But I'm thinking it's more likely the tape itself. They are all over 20 years old and were not stored optimally (best practice is not to store in a paper bag). As Sharc wrote 'garbage in / garbage out'.
Appreciate all the comments and will keep working through it and try things mentioned in the thread, reporting back with any updates.

-D

[Bwaak]

Is this a long play recording?

[Bwaak]

I would deinterlace twice: first into 60p, second into 30p using only the top field, which seems to work fine (one of the heads on the VCR is dirty or damaged?) Then put both videos on two tracks and either replace individual fields/frames or mask the bottom part on the 60p track wholesale. Granted, the latter approach looks like crap on fast pans.

If the glitches are not overwhelming, like several times a minute, I would just replace individual fields/frames. I suppose you will be editing your video anyway. So I would edit it first, with glitches, it would result in, like, 3-5 minute video, then I would replace the remaining glitches manually.

[Derrydavis]

Quick update I borrowed another capture device and the video looks much better. 720x480 shows up and no glitching so far. Appreciate all the responses, such a great community.