ATI capture: jagged lines in some frames

[panamayellow]

I'm having trouble with capturing, and I don't know enough to put a name to it. Even knowing what the rest of the world calls this problem would be a help. (of course a solution is also desireable!)

Please help me to figure this out (or just point me at where it's already described - my week of searching here hasn't found it for me!)

Here's what's happening:
In some frames, some parts of the video have a jagged appearance. Mostly, the effect seems to happen to straight lines.
Here are two frames from a capture that has this problem in a big way. The source is a CLV laserdisc, connected via s-video through a TBC-1000.

In this frame, the edges of the airplane's wings have a "striped" or "jagged" appearance.
http://www.geocities.com/panamayellow58/jagged.jpg

In this very next frame in the capture, the wings look more like they should:
http://www.geocities.com/panamayellow58/smooth.jpg

I see this kind of effect come and go in various parts of some frames of a capture.

I've tried leaving the TBC-1000 out. I've tried capturing using MMC (9.02) and VDub. ...to no avail.

My capturing environment:
ATI AIW 9600XT
ATI MMC v9.02
VDubMPEG v1.5.10
MSI neo (AMD64) MoBo
512Mb ram
Pioneer DVL-700 laserdisc player
DataVideo TBC-1000

Thanks in advance for any pointers...

[lordsmurf]

Quit deinterlacing.

http://www.digitalfaq.com/capture/interlace.htm
http://www.digitalfaq.com/capture/atiavi/atiavi.htm
http://www.digitalfaq.com/capture/atimpeg/atimpeg.htm

[trock]

Are you talking about when you view it on your PC? If so, it's perfectly normal and won't be that way when you burn it to DVD. If it's on your burned DVD watched on a TV set then don't de-interlace, as Lordsmurf suggests.

If on your PC, it's because your source is interlaced and your PC monitor is progressive and thus shows the jaggies.

[panamayellow]

Actually, I don't intend to be de-interlacing and am not doing so.

In the MMC wizard for the preset I'm using to record the LD, the "de-interlacing options" option is set to "encode interlaced" (the default).

Can something else be causing this problem? (or is the MMC lying to me about what it's doing? )

I'm using MMC set in the manner that LordSmurf has suggested on digitalFAQ (with the slight exception of experimenting with video soap).

I've been fighting this one for a couple of weeks (admittedly by trial-and-error).

Thanks for your responses. Any more suggestions?

[redwudz]

If you are viewing the file on a PC, you need to use something like PowerDVD player, which can handle interfaced video. Have you tried the video on a TV? trock gave a good explanation. What you describe is typical of interfaced video played on a non-interface capable player..

[panamayellow]

redwudz,

Thanks for the reply. I see the same effect on the computer screen and on the TV. I"ve been using DVD-RW disks and it's a good thing, else I'd have lotsa coasters around here.

In summary, I'm not de-interlacing (that I know of) and I see the same effect on both the PC and TV.

Thanks for your response.

[lordsmurf]

This is also a fatal flaw of 720x480 resolution.

Stick to 704x408 or 352x480.
Try those.

Honestly, it looks like something with interlace. I'd want to see a motion clip, not stills, to make better judgment call.

[junkmalle]

You've obviously captured a movie that has been through 3:2 pulldown (as you would expect from a laserdisc). Some pairs of video fields are from the same film frame (your second picture), some from two different frames (your first picture). Although it looks bad on your computer monitor it should appear normal on a TV (you don't see both fields at the same time on TV) if you have the correct field order set -- so check your field order.

[junkmalle]

Oh, if you want to create a video that looks good on both the TV and computer you can try to inverse telecine back to the original 23.976 fps film frames. I don't know if this is practical with AIW caps though (dropped frames throw off the telecine pattern).

[panamayellow]

Here's the clip (actually two small ones) that LordSmurf asked for:

http://www.geocities.com/panamayellow58/first.mpg
http://www.geocities.com/panamayellow58/second.mpg


Here's how I'm capturing the LD....
Settings for ATI MultiMedia Center 9.02 MPEG capture

MPEG-2, NTSC,
Resolution: 704x480
De-interlacing option: Encode Interlaced
Inverse 3:2 pulldown: not checked
Record cropped video: not checked
Audio: 48khz, 16bit, stereo
GOP: 4 P frames, 2 B frames, closed GOP
VBR, max 9Mb, target 8.5Mb
Motion estimation quality: 99
Audio encoding: 256kbit/sec
Video soap: light (default - combo filter 1 @ 19%)
Max file size: windows limit

junkmalle:
Is "inverse telecine" the "inverse 3:2 pulldown" in the above list?
Field order: my understanding is that field order in ATI cards / MMC is fixed and can't be changed. Is that right?

Thanks for your continuing interest...

[panamayellow]

One last thing,

The jagged lines are there on the TV and the PC both.

I get the same result when I capture using VDubMPG (set up per digitalFAQ suggestions) and encode with TMPGEnc 2.5 (set up ditto).

[junkmalle]

Is "inverse telecine" the "inverse 3:2 pulldown" in the above list?
Field order: my understanding is that field order in ATI cards / MMC is fixed and can't be changed. Is that right?

I don't have an AIW so I can't answer those questions definitively. I'm sure LordSmurf will eventually chime in.

I believe the "inverse 3:2 pulldown" is the setting in question but I'doubt the software will be able to do this in realtime while capturing.

Field order usually is fixed with any particular capture device. Apparently the way you're capturing the interlaced video is backwards from the way a DVD wants it. You should be able to reverse it in the DVD authoring software. Or, as you mentioned capturing with VirtualDub, on the conversion from AVI to MPEG.

I looked at your two MPEG samples and they both are telecined film. The second one was easily IVTC'd with VirtuDubMpeg as the telecine pattern was consistent throughout. The first one suffered several breaks in the telecine pattern. There was very little overlap between the two so I couldn't tell if this is because of dropped frames while capturing, or if the source had the problem (I doubt it's the laserdisc on a first rate film like that though). I did see several MPEG encoding errors in the first file -- not a good sign.

If you can correct the field order you're probably better off just going straight to DVD with a 29.97 fps interlaced MPEG file. I've seen Smurf deprecate IVTC a lot so I suspect it doesn't work well with AIW captures.

[Nelson37]

Field order for AIW not changeable in software, SFAIK, possibly a registry edit. It is NOT fixed in hardware, as I saw it change when changing MMC versions on the same card.

"Remove 3:2 pulldown" is indeed IVTC, and on a good feed it does in fact work quite well. About the same as using AviSynth. As always, very sensitive to dropped frames.

Unable to DL the clips, though the stills do kinda look like maybe field order. You could try a short re-encode test with the field order reversed. Unfortunately, if that does turn out to be the solution I don't know of any way to reverse this in real-time.

Would also suggest a slight lowering of bitrate, as with MMC's lack of precision in adhering to specified bitrate you may be exceeding maximums with audio added.

[lordsmurf]

On-the-fly IVTC looks like crap. If you need that, be sure the source will cooperate, and do it in a re-encode (capture AVI).

If it's something as simple as reverse field order, do this:
http://www.digitalfaq.com/capture/atimpeg/restream.htm

Be very sure to use a good version of ATI MMC. I suggest 8.7 as most stable. Then I have 9.0 working perfectly too.

I still need to see a clip.

[panamayellow]

junkmalle,
First, Thank you for your suggestions. I think I understand that the source (CLV LD) has been recorded onto the LD at 29.97fps from its original film 24fps in a process called "telecine" so that the LD will look right on an NTSC TV. I'll try capturing the source with virtualDub into an AVI file and then attempt to (1) test changing the field order and (2) play with the fps setting (24 or 29.97) to see what looks right. I'm also going to do some more research here on videoHelp.com to learn more about "telecined" sources and how best to deal with them.

I assume (hope!) that the second clip has MPEG errors because I chopped it into progressively smaller pieces using mpeg-vcr until I had something reasonable for you and others to download.

Nelson37,
I will be lowering the bitrate from 9k to probably 8k max as I hadn't before known about MMC not controlling bitrate reliably. Where would we newbies be without those of you who've already been through it?

LordSmurf,
I've sent you email on digitalFAQ.com.

[junkmalle]

I'll try capturing the source with VirtualDub into an AVI file and then attempt to (1) test changing the field order and (2) play with the fps setting (24 or 29.97) to see what looks right.

In VirtualDub you want to play with the Inverse Telecine section at the bottom of the Video Frame Rate Control dialog.

You can try the "Reconstruct from fields - adaptive" setting but I find that it lets lots of interlaced frames through and results in a jerky video.

I usually use the "Reconstruct from fields - manual" setting along with the Offset variable. There are five possible settings for the Offset, 0 to 4. You have to use the right one. Try different values until you find one that works. Set it at 0, go back to the main window and press the Play Output button. watch the output window for interlaced frames. If you see any, go back and try 1. If that doesn't work go back and try 2... I've never had to use the "invert polarity" option.

If your capture isn't perfect (or if the film was edited on video tape) you may find that the telecine pattern gets out of sync now and then, forcing you to encode in sections. Sometimes I get through a whole movie with no problems (10%). Sometimes I have to encode in two or three sections (80%). Sometimes there are so many breaks (every camera cut!) I just give up an leave the video interlaced (10%).

If you find a break after a while you don't need to go back and convert the good section again. Just stop VirtualDub, start another instance of the program, open the partial file, find where the break occurs, and output with Direct Stream Copy up to that point. Then go back to the first instance of VirtualDub and start encoding again from the break point. You'll probably have to change the offset value for each section.

I guess that sounds confusing but once you get the hang of it it's not very hard. Let me know if you run into problems...

[panamayellow]

junkmalle,

I'm going to spend some large part of tomorrow experimentiing with this. I am sincerely grateful for your suggestions.

As with so many things, just as I start to think I have learned something about something, I come to realize that I haven't even got halfway there yet.

grin

[Sulik]

You might want to experiment with the built-in Inverse 3:2 pulldown in MMC (it's the same than Inverse Telecine).
I found that it worked quite well if the signal is clean.