Why do I lose frames?

[jeremypps]

Hi everybody, here I go again with another question.
My system specs are:
athlon 900mhz, 448mb ram pc133, quantum 30gb 7200rpm + ibm 40gb 7200rpm (new, bought just for capturing ,sigh ...), ati aiw 128 agp sb128pci.
If I try an avi capture (uncompressed or huffy): no frame loss at lower resolutions, nearly a disaster at 704x576;
divx capture with virtualdub: frame loss even at 352x288 very low bps, specially with fast movement pictures.
Is all this regular, or because of something that could be wrong in my system?
Many thanks in advance.

[jeremypps]

if I miss to specify something please tell me, I'm looking for any help, thanks.

[jwhitlow]

You need a seriously fast hard drive to capture at full resolution AVI!

I am capturing to MPEG-1 these days, but I was initially capturing to AVI. Like you, I wanted to capture in full resolution. I was able to do it, but not with a single hard drive. I got an Adaptec 2400A RAID controller and put 4 80GB, 7200RPM drives on it in a RAID-0 stripe. I initially built the RAID using RAID-5, but I was still getting frame drops (less than a single drive, though). If you have a motherboard with on-board RAID, you might try putting two drives on it in a RAID-0 stripe and see if that is fast enough.

[Clear_Signal]

jwhitlow,

What software are you using to capture to MPEG-1?

[jeremypps]

thank you very much jwhitlow, now I feel better 'cause I know what happens to me can be normal and not depending on something wrong with my system.
unfortunately my motherboard is not a good one, but I'll see if I can capture a bit less resolution (i.e. 640x480), if it's so then it's ok for me.
Many thanks again !

[jwhitlow]

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On 2001-11-15 06:57:55, Clear_Signal wrote:
jwhitlow,

What software are you using to capture to MPEG-1?
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I use the ATI MMC that came with my ATI AIW Radeon (MPEG-1, I-Frames only, 7.5Mbps, 640x480). I use TMPGEnc to encode to VCD:
352x240 29.97fps VBR 1850kbps, Layer-2 44100Hz 224kbps

[Clear_Signal]

Great, Thanks

I have the same card, so I'll give those settings a try.

How long does it take you to encode, say 1 hour of video, in TMPGEnc?

<font size=-1>[ This Message was edited by: Clear_Signal on 2001-11-15 08:35:02 ]</font>

[Shabubu]

You don't need to cap at full resolution as TV source doesn't have it... so your capping excess information that isn't there, the com can't cope so you drop frames !!!!

Cap all the scanlines (vertical), PAL is 576, NTSC is 480.

Width, cap at 384-400, then resize. This applies even if your making an SVCD.

Open in vdub, deinterlace, resize then frameserve.

[jwhitlow]

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On 2001-11-15 08:33:59, Clear_Signal wrote:
How long does it take you to encode, say 1 hour of video, in TMPGEnc?
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After I edit out the commercials, I have ~45 minutes of video. Using my 2-pass 1850 VBR, highest motion setting template, it takes about 10 hours to encode.

[jeremypps]

10 hours? gasp.
shabubu, thanks for the info, I guess (and hope) this could be the main problem. Anyway, I took a look at almost all options in virtualdub and didn't find anything to specify how to resize image.
could you please tell me exactly all the steps, or tell me where to find a good guide for resizing and for frameserving?
thank you very much anyway, and nice weekend to everybody!

[mpack]

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On 2001-11-15 11:19:41, Shabubu wrote:
You don't need to cap at full resolution as TV source doesn't have it... so your capping excess information that isn't there, the com can't cope so you drop frames !!!!
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What do you mean, "it isn't there"? Standard TV resolution is 704x480 (NTSC) or 704x576 (PAL), so the information certainly *is* there!

Also I notice you recommend deinterlacing even though jeremypps hasn't said what his ultimate goal is. If that goal is SVCD played back on a TV then deinterlacing is a mistake. For VCD deinterlacing is necessary.

To jeremypps:

No one else seems to have suggested that you enable DMA on your hard disk. Warning: old HDs and Windows prior to W98 may not like DMA for the hard disk.

[Shabubu]

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On 2001-11-16 14:43:26, mpack wrote:
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On 2001-11-15 11:19:41, Shabubu wrote:
You don't need to cap at full resolution as TV source doesn't have it... so your capping excess information that isn't there, the com can't cope so you drop frames !!!!
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

What do you mean, "it isn't there"? Standard TV resolution is 704x480 (NTSC) or 704x576 (PAL), so the information certainly *is* there!

Also I notice you recommend deinterlacing even though jeremypps hasn't said what his ultimate goal is. If that goal is SVCD played back on a TV then deinterlacing is a mistake. For VCD deinterlacing is necessary.

To jeremypps:

No one else seems to have suggested that you enable DMA on your hard disk. Warning: old HDs and Windows prior to W98 may not like DMA for the hard disk.


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http://www.digital-digest.com/nickyguides/video-capture.htm , look at the bit about half way down that says VHS resolution, if you don't believe him I have other sources of info on the subjuect ( https://www.videohelp.com/phpBB/viewtopic.php?topic=66124&forum=2 ). In short TV's aren't like monitors, so there horizontal resolution IS NOT 704. It's all about Kell factor. I recomended de-interlacing cause that's what I personally do, I always dislike interlaced pictures (mainly cause I watch on a PC).

To jeremypps, the resizing feature is in filters, click video>filters. Then add, choose resize and resize bicubic (for going up) or bilinear (for going down).

[vhelp]

mpack,

I think you posted your part of your response out of order.
You were suppose to mean, ..."For VCD deinterlacing is necessary. "
...was suppose to be: "FOR SVCD, DEINTERLACING IS NECESSARY"
...as VCD is 352x240 (dropping the 2nd field)

[mpack]

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On 2001-11-16 18:35:40, vhelp wrote:
I think you posted your part of your response out of order.
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No, I had it round the way I intended.

For SVCD de-interlacing is *not* necessary, since SVCD uses MPEG2 which understands fields and frames and can play these back correctly on a TV, getting smoother (50 or 60 fields per second) motion in the process. Although some people argue that you should deinterlace anyway my own opinion is that you *always* end up with blurry motion artefacts so the best thing is just to leave the source the way it is.

VCD on the other hand uses MPEG1 which does not understand interlacing, so you have no alternative but to deinterlace for VCD (if you throw away one of the fields, I count that as deinterlacing!).

[jeremypps]

well, as I've said in another post I'm afraid ati newest drivers (and also the ver before) give me some problems, I installed the old ones and things seem better.
I've found the resizing filter, I'll try it soon, after I try some captures 352x576.
After all this talking I'm completely confused about interlacing, deinterlacing and so.
My final goal is pal xvcd (maybe divx later on, but now I want to play my home shootings on my standalone dvd player), so, as I understood, I should capture 352x576, then I got lost.
Should I use deinterlace filter togheter with resize?
After this dark step, I should frameserve to tmpgenc (hope I won't do a disaster ...), play with settings (I still didn't see many topics about tmpgenc around, I'm probably too late), encode and burn.
Please tell me if I understood something wrong!
Thanks a lot to everybody !!!

[mpack]

Its hard to answer questions about 'xVCD', since the 'x' in there really means "not ".

However, (x)VCD is usually taken to mean MPEG1, which means that interlacing is not allowed in the final MPEG, so yes, at some point you need to deinterlace. Whether you deinterlace on the fly during the capture or do it afterwards in VDub or tmpgenc is a matter for your own preference.

[jeremypps]

ok, now I got it, thanks mpack !!!