ATI Capping from VHS - hardware advice and DivX Encoding question from newbie

[plucky]

This is a 2 part question, the 2nd of which can be ignored if you don't have any idea (I just posted the bottom part in the DivX newbie forum, copy-pasted here since it's a related question, and I don't have time to retype right now, you'll see after how much I type for the first part ;) ).

Executive summary: What would help cap better/faster/harder/stronger?

About 2 weeks ago I purchased a ShuttleXPC to use as a media PC in the living room. Put the sucker together with the hardware I could get my hands on, set it up and off she went. Woot.

Before going on, here's the specs (like below, but with more info).

ShuttleXPC SK41G - Integrated Avance AC'97 Audio & NIC
1GHz Athlon CPU
512MB Corsair PC-2700 RAM
System Drive: Maxtor 8GB junk (single drive, Primary)
Capture Drive: 40GB Seagate 7200 RPM IDE (Master, Secondary)
DVD-ROM: Old Creative 5x (Slave, Secondary)
Video: ATI AIW Rage 128 PRO 32MB PCI
OS: WinXP (and no, I'm not installing Linux on this ;) )

I've tried capping both with VirtualDUB and ATIs MediaCenter (v7.1, because thats what they say you can use with the old Rage 128 Pro), with about the same results (actually, the ATI looks nicer as I haven't tried any filters in VirtualDUB to take care of the yucky interlacing problem). I'll give a run down of how I'm capping, the results, and then ask "what might help"? And yes, I've read most every guide out there, but it always seems the questions I have don't pop up, I'm glad to have gotten as far as I have through hours and hours of trial and error!

Dropped frames SEEM to be a big problem (see the 2nd part of the post for why I think they are). The only way I have been able to capture with NO dropped frames is to capture at 640x480, MPEG1 or MPEG2, I-Frames only. This gets nice big files, and they look OK. Not amazing, but they're not bad. After getting that far, I have tried many other settings, and the best picture I've been able to capture has come from 640x480, MPEG1, 1 P-Frame in Group (I also tried 2 P-Frames, 2P 1B, etc etc). This resulted in around 18% lost frames, but a slightly better looking capture (I even ran a whole batch of different tests buy my girlfriend to see which ones looked best).
I tried capping as per the Doom9 guide using VDub and Huffyuv compression, but had horrendous results (unless I turned the settings down, which worked better, but still nowhere near as nice as the Multimedia Center).

So, the big questions I have at this time are as follows:
1) If you care to read the BOTTOM section, how much do the dropped frames really effect the re-encoding of the files?
2) What would help MOST to capture at a better quality? I'm guessing it is NOT CPU (1GHz is plenty for how little it is really taking care of), RAM (it's barely touched) or Disk (which is the reason I installed the 2nd HDD, just to eliminate the "capping to the primary drive" problem), though each of these might have a LITTLE effect. I'm guessing it is not the sound-card, as there are 0 dropped frames when I'm capping "I-Frames only" (though this is just a guess), and the audio ALWAYS captures fine. How much does the video card effect this particular situation? It IS only a PCI card, so that leaves a bit of room, but i have no idea if it is actually a bottleneck at all, as I have NO expertise at video-capture cards. Would AGP in itself be helpful (i.e. AGP version of same exact card, 32MB ATI AIW Rage 128 Pro)? Would it take a huge upgrade there to make a difference (not noticable until you get a AIW 9800?) Or does the card make no difference at all in this instance and I'm just looking in all the wrong places?

So, I hope I've provided enough information to be helpful in anyone knowledgeble being helpful to me :) I've read most guides I could find, but most don't touch upon some of my issues, and I've tried to eliminate as many others as I could along the way. And because of the 5 day wait to post to the forum after registering, I've had those extra days to add more puzzles to my pile (darn 5 day wait, I usually read everything I can and register as a last resort :) ).

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Part 2 (the repost from DivX Forum, figured I'd include it here just for completeness)

Executive summary: Multipass encode ends up with video running at nearly 2x the correct speed.

I am just starting to cap and encode (as I just got a new ShuttleXPC and hooked it up to the TV/Cable/VCR/etc). My first real project is tranfering some old VHS tapes of some shows that were canceled and not available anywhere else (so sad), and then encoding them with DivX.

Before going on, quick PC Specs:
1GHz Athlon
512MB RAM
Capping to 2nd channel IDE 7200RPM 40GB HDD
Using a 32MB ATI AIW PRO 128 PCI

The best resuts I have had with the CAPPING are MPEG1 @ 640x480, 1 P frame per set. This results in a large percentage of dropped frames (~20%), but the resulting video looks fine. (as a note, the only way I can cap with NO lost frames is capping with I Frames only, but it's 0 frames lost looks worse then the 20% loss with P frames, but this is one of the questions I'm going to Doom9 with ;) ). Audio is grabbed at 22KHz, 16-bit stereo.

For a 3 hour tape I ended up with an 8GB file. Next step, chop it up and encode with DivX.

Try 1) VirtualDUB - had horrible trouble with audio/video sync (not that gradual loss, just plain horrid). Found the "change frame rate so video and audio times match", much better, but still some problems, likely because the 20% frame drops aren't perfectly proportional or something beyond me :)

Try 2) TMPGEnc - Worked great! The only problem was that in some spots the picture quality was kinda stinky. Since this was a 1 Pass encode, I decided to try a Multipass encode (after doing some RTFM that is).

Try 3) TMPGEnc with Multipass - After the 3rd pass I checked the video, and the video speed was around 2x the rate it should be! No gradual audio sync loss here, a HUGE problem, but that's not the audios fault it would seem, as it played along at normal speed, it was the video that was running at 2x the rate it should.

So the question at hand is: What am I messing up that is causing the video to crank along so quickly after a Multipass encode that is not happening in a 1-Pass encode (using default settings) It is possible I may have made some setting changes when doing the Multipass, but it would take another day of encoding (unless I chopped the file nice and tiny for MORE trial and error than I've already done the past week) to be sure I didn't.
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Thanks for any help!
Eagerly awaiting help (while encoding more in the background for more compression tests, poor PC!)

plucky

[bb]

Welcome to the forum, plucky.

If you have such big problems with dropping frames, we should investigate your system. I suggest you disable all services you don't need (Control Panel, Administration, Services), and that DMA is enabled at least for your capture drive.

What's your CPU load while capturing (see Task Manager)?

The graphics card can be a bottleneck, I believe. But another thing to look for is the onboard sound: I had a PC which would capture only with a separate sound card installed, because the AC97 chip caused too much CPU load.

bb

[scharfis_brain]

it is a very common problem, that bad VHS causes framedrops.
So try to capture from life TV. Has the TV-capture framedrops. If yes, how many compared to a VHS-cap?

[plucky]

Thanks for taking an interest, it's early morning now for me (9AM is early to me ;) ), and I'll try to answer as best I can (though I'll answer what I can to start, and maybe more when I get home and can turn the machine on).

bb - Yup, everything extra is turned off and DMA is on. As for CPU load, I'll have to do this from memory at the moment, but I can check again later. With ATIs MMC, Task Manager reported a high CPU load (near 100%), yet the process list, even when told to show ALL processes, didn't come near the total. Puzzling. Even if it is the sound taking the CPU, shouldn't that at least show somewhere in the process list (services, svchost, anywhere?) I can certainly try capping with no sound tonight (I may have tried that already, but I don't specifically remember doing it, though I do remember reading it).

scharfis_brain - I had the same results capping from TV (actually, I did most of my tests capping from TV, less effort then torturing the poor old VHS tape).

I'll check the sound tonight, though I think I may have tried that, it's just been so many days since I signed up for the forum, I've forgotten some stuff ;) ).

plucky

[bb]

100% CPU is definitely too much, so it's no surprise that you drop frames. You could try to capture to MJPEG (I use PicVideo, which is fast), which worked nicely on a 1.3 GHz Athlon, whereas Huffyuv failed at full PAL resolution (I guess because the data rate was too high).

It happens that I just converted a wedding VHS video to DVD. I used MJPEG as intermediate format, then used advanced AviSynth filtering and encoded to MPEG-2 using quality settings. I could've captured to MPEG-2 directly, but in no way I would have achieved a comparable quality.

bb

[Sulik]

Is 7.1 the latest version of MMC you can use ? 7.7 was way more efficient for capturing MPEG.
Regardless, on a 1GHz Athlon, you should be able to capture full D1 I-frame only at 8+Mbps without dropping frames. Try keeping I-frame only and increase the bitrate as much as you can as long as you don't drop frames (go up to 15Mbps).

[ppera2]

For full size Mpeg2 capture 1GHz CPU is not enough. XP 1700 is cheap, if you can find some used even more cheap...

[plucky]

OK, here's where the "noob" status comes in. Even though I read everything, and tried to follow everything, I did mess up at one spot.... I'll blame it on V-Dub not being the greatest at saving settings, yea, yea, thats it ;)

Let me quote from the Video Capture guide...
"but please don't use any audio compressor on the fly to avoid problems."

Oops, that's where the BIG problem was.... V-Dub was set to do mpeg compression (maybe I set it that way, but oops). As soon as I set it to uncompressed audio it captured SO much better. I tried the Pegasus MJPEG for kicks, and could use the quality/compression setting at 17 and could capture 640x480 (now I can try the 704x480 or 720x480, whichever it was for my card, I'll have to read again). I'll have to experiment some more, as the initial tests were somewhat screwy (when I had the quality setting at 18-20looked like bad audio sync on a STRAIGHT CAPTURE , not a recompress, which I've never heard of before, but it was a short test, need to play more).

The thing that made it harder for me to figure out is that the 7.1 (or 7.2, which uses the TV 7.1) doesn't have any option to capture the audio uncompressed, and no "no audio" option (maybe muting the Line-In for recording would work, but I didn't try that).

"Is 7.1 the latest version of MMC you can use ? 7.7 was way more efficient for capturing MPEG."
Actually I downloaded versions 7.7 and 8.8 to try tonight. 7.7.0.1 would install fine, but the TV part would not run (would show it's splash screen and lock there). Tried 7.8 as well with the same results (7.8 uses TV 7.7 anyway). 8.8 wouldn't install, and I know why, but since 7.7 didn't work, I don't think I want to go through the hacking necessary to get 8 to install (editing the msi installer, which is something I've never done before anyway).

So, I guess my next question is this, the guide says "I have tried out several filters and come to the conclusion that "Deinterlace MAP" by Shaun Faulds works best for me." Is this still the way to go for deinterlacing the results? The MMC seems to do a very nice job of deinterlacing while it captures, any filters for VDub make as pretty a result as the MMCs job? Most of that is beyond me technically :)

Thanks for the input, and too bad my RTFM didn't do it for me for whatever reason (heck, I went through step by step, so I wonder how I missed that...) ARGH, there's just way too much to capping video right now, how long till I can go "click" and capture a perfect quality tiny file with no middle steps? Purchasing a ReplayTV to plug into my network? But can it do VHS tapes? :)

plucky

[ppera2]

plucky:

I think that you already got all answers in this thread...

Others are in forum rules and guides...
But, to 'elaborate' it: no perfect capture at all. Even with postprocessing you will not get something perfect. Even on fastest machines you cannot use some filters, because they are slow.

Buying some external card can be good solution, but real quality is expensive...

[plucky]

Yes, sorry, I'm getting OT and onto questions that are probably covered elsewhere (that I hadn't looked for before, as they are new issues for me :) ).

I hope there's a study somewhere on here of PCI vs. AGP capping at it's most basic level!

Thanks, and here's hoping I can get some stuff capped that'll be good enough to share :)

plucky

[plucky]

I have been capping pretty successfully for some time by capping "I Frames Only", but finally had a chance to experiment on one of the questions I had - PCI vs. AGP.

A friend is rebuilding a system at home and let me borrow a 2x AGP ATI 3D Rage Pro. Great card to compare with the one I am already using (PCI ATI 3d Rage Pro). Same card, different bus, can't ask for a much better PCI vs. AGP comparison then that!

Anyway, to make a long story short, with the AGP card on ANY capture settings I gave it had almost no frame dropping. Nada. Of course, even though it reported 0%, some settings still didn't look up to what they should, as if it was dropping SOME, performance was MUCH better. Using VDub I could even capture straight to DIVX with almost the same quality.

So, at least for anyone using a Shuttle XPC G41 (and likely anyone with a similar architecture), going AGP over PCI, even at the lower end (2x AGP, I didn't try at 1x, and I've already removed the card so I won't be testing that ;) ) might yield much better results, and much less frustration at trying to find the capture settings that will actually give you something you can watch!

Well, now to go buy my own AGP card.

plucky