Surely my computer spec isn't that bad!??!??!?

[Lambchop]

I've got the following spec:

Windows 98 No details available
1000 megahertz AMD Athlon
128 kilobyte primary memory cache
256 kilobyte secondary memory cache Board: ASUSTeK Computer INC. A7A266 REV 1.xx
Bus Clock: 133 megahertz
BIOS: Award Software, Inc. ASUS A7A266 ACPI BIOS Revision 1006 08/20/2001

70.05 Gigabytes Usable Hard Drive Capacity
10.69 Gigabytes Hard Drive Free Space
HP CD-Writer+ 8200 [CD-ROM drive]
MATSHITA CD-ROM CR-588

Installed Memory
256 Megabyte Module Size - 1 Installed
4 Memory Sockets are Empty

Matrox Marvel G400 AGP - English [Display adapter]


and have had trouble capturing bigger than half screen size with my Matrox G400TV using Mjpeg compression, as it interlaces the image when it shouldn't do, and you can't de-interlace as you go. (I'm using VirtualDub by the way). Anyway, I'm trying out the HuffyUV codec, and can't seem to capture above half screen size without losing LOADS of frames. Surely I should be able to with my processor?? Is there anything obvious I am doing wrong?

Basically, I'm setting for 24bit RGB, with 640x480 resolution, then setting the compression to HuffyUV, with best or medium compression. I can't capture without any compression either without losing frames. First question I should ask is if I'm going about it the right way??

thanks people!!

[impmon2]

Well, your spec didn't mention if you have a second hard drive. It is usually a good idea to have a hard drive other than the one with OS on it for capturing to. And if you want to keep the high transfer rate (ie ATA-66 or 100) then you'd have to hook it with the main hard drive and leave both CD-ROM and CD burner on a secondary IDE (They'd drag any hard drive down to snail pace).

Also try using no compression. It'd require a lot of disk space, upward of 20-30 MB/sec but since there's no compression to do the CPU's free to grab as fast as it can go.

As a last resort, you can always use a shot gun as an excuse to get a new PC.

[Lambchop]

Thanks for the help....yep, I've got a second HD, but its slower than my usual HD, which normally doesn't have a problem with video (60gB 7200rpm maxtor ATA100). Mind you, that's probably slowed down by the second HD, so I'll try disconnecting it too!

[homerpez]

Nuh-UH! Leave that hard drive ON, and use THAT instead (or replace it with a bigger one)

That sounds like a familiar scenario to me, I also have a 1GHz Athlon, 512MB RAM. Sadly, things like MPEG compression can either work in this setup, or not. In my case, NOT.

However, I can capture 480x480 with VirtualDub, Huffy codec, and no worries. The lack of the compression really does wonders for things like dropped frames, desynch, or corrupted capture files.

But important in any case, do NOT use the hard drive your OS is on. Things are being kept busy on there, usually at the worst possible times.

[Lambchop]

Well, my smaller HD is a 10Gb 33ATA 5400rpm, and is pretty slow, so I assumed it wasn't a good idea. Ideally, I'd wipe all the rubbish off there (its my old HD, which is full of stuff I havn't got round to backing up) and put a 2nd OS on there to work off onto my larger, faster HD.

When I try to record to RGB, fair enough, the HD light goes haywire, but not quite so much with huffy compression, so I assumed it wasn't a HD issue? I'll have a play and see! thanks

[Shabubu]

Believe it or not the only reason your losing frames is capping in RGB. Huffyuv wors best in YUV (it has to convert YUV>RGB and back). Your capture card works in YUV, so does MPEG.

Basically start using YUY2 and all your problems will dissapear..

[loveturtle]

disable virtual memory-virtual memory will cause you to drop frames like crazy

[Shabubu]

DO NOT DISABLE VIRTUAL MEMORY.... (yet anyway)

Again, just try the YUV thing first. If that's not the problem then you can start trying more extreme stuff.

[Lambchop]

thanks people!

shabubu - I've tried with the <--convert to YUY2 option in the huffy dialogue box, but still have the problem.

how would I disable virtual memory? and is that a dodgy thing to do? you seem to think it is drastic....

[Shabubu]

No not in the huffyuv settings, in the virtualdub format settings. If you set your card to cap in rgb it has to do this

TV>YUV>RGB>HUFFYUV(RGB>YUV>COMPRESSION)>HARD DISK

With the capture format set to YUV you get this

TV>YUV>HUFFYUV>HARD DISK.

You can see where I'm going with this.

[Lambchop]

In the format dialogue box, I've only got:
RGB (8 bit)
RGB (16 bit)
RGB (24bit)
or MJPEG

[Shabubu]

Ahh, now that REALLY sucks. Unfortunately you can't use huffyuv. Try an avi format that can work in RGB. Trust me this isn't a virtual mem problem, it's that all the format converting is overloading your processor (i'm surprised it kept up as well as it did). If you go into the settings for PicVideo MJPEg or the like you can change the horizontal line threshold before it interlaces, effectively disabling the interlacing feature. Be careful though as it may overwrite your hardware codec.

[Lambchop]

ah, I think I understand now Shabubu, thanks!

Isn't PicVideo another MJPEG compressor? Is it one you have to pay for to use?

[Shabubu]

It is, but it's the only one I have experience with. The matrox one should have a similar setting in it's setup (Interlaced threshold or the like)

[Lambchop]

I found the info for myself - didn't realise I was being so lazy!

I think before I do that, I have another crack at trying to understand why I can't get rid of this interlacing problem with the matrox hardware mjpeg compressor....

[Lambchop]

Oh, there doesn't appear to be such a setting in the matrox mjpeg settings - just speed and quality

[sherman]

I have the same card with a P3 866. I can capture 704x480 from TV
using MJPG compresion @ 10:1. (Use the MJPG hardware compression built right in your card, with your 10 gigs free this will give you room for close to 1.5 hr of video). I believe this only requires about 2.5 Megabytes a second Hard Drive Rate. What does the Matrox bench mark test say is the speed of the drive you are using to capture. If it does not find your drive is fast enough it won't let you capture at full resolution. Your processer is not the problem. Virtual Dub reports that my P3 is only working @ 20-25% during capture.

Sherman

[Lambchop]

Hi Sherman

I can capture using it with no problems, apart from the fact that I am getting a funny interlacing effect creeping in when I make the jump from half screen size to full screen size, as shown:

full screen

half screen

[loveturtle]

do disable virtual memory
right click on my computer choose properties
click on the performance tab and choose virtual memory
disable it then reboot and try your capture
normally windows writes to virtual memory when you capture Then to your capture file
if you have it disabled it goes straight to your disk
also you might try disabling write behind caching on your harddisks
you can reenable virtual memory after the capture
I ran with no virtual memory for 2 months on only 256MB SDRAM
I now use 512MB SDRAM no problems in anything so far and the system overall is faster

[Roginator]

I have an almost identical system.
A7A266, 512MB DDR RAM, 2-60GB 7200rpm drives

When I was capturing from a TV card, I found that AVI_IO performed much better than VirtualDub. Give the trial version a try and see if you have the same experience.

The weird lines you see are a result of our weird TV transmission standards. They broadcast half of a frame, followed by half of a different frame. If there's any movement in the scene, you get those nasty interlaced lines.

You can do 3 things: 1) Capture at (or reduce to) a max height of 240 which only captures one half of the frame. 2) Deinterlace afterwards to attempt to blend the two halves together, or 3) Do an IVTC or Inverse Telecine which takes the frame halves and joins them in the proper order. This also eliminates 20% redundant frames resulting in far better compression.

For details, read all the messages in these forums <g>

[sherman]

OK Boys Corect me if I am wrong. If you capture at a vertical resolution of 480 the AVI must be interlaced. If you are going to encode to standard VCD which is 240 vertical resolution and de-interlace while encoding the resulting MPG would then look OK.

Labchop this image that you put in your message was it captured using your cards built in hardware MJPG compression using either Virtual Dub or Matrox PC-Remote Program. When I do this and play the captured AVI back in either Vurtual Dub or PC REmote or Windows Media Player the Video looks good. I encode mine to XVCD at 480 X480. The resulting MPEG then looks Interlaced like your posted image but playes back OK in my DVD player.

I don't know how to post an image of one of my captures but if you Privite Message me with you EMAIL adress I will send you a captured image.

Sherman

[impmon2]

You usually don't see the odd/even fields on TV because, well, TV were made to display interlaced fields. They are 60 fields per second, 30 fps.

The reason they usually show up as ugly lines on PC monitor is because the PC monitor is capable of display video at much higher rate than TV can (such as 120Hz, 180hz, and even faster) so each pixels on the monitor changes fast enough that you can see each lines. TV's refresh rate is slow so the interlaced field blends more smoothly.

If you were planning on viewing captured vids only on computer monitor, either keep the capture below 240 or use the deinterlace option in some programs. If it's going to be for TV, it should be OK leaving it as they are at 480.

[pharlap]

Well, your spec didn't mention if you have a second hard drive. It is usually a good idea to have a hard drive other than the one with OS on it for capturing to. And if you want to keep the high transfer rate (ie ATA-66 or 100) then you'd have to hook it with the main hard drive and leave both CD-ROM and CD burner on a secondary IDE (They'd drag any hard drive down to snail pace).

Also try using no compression. It'd require a lot of disk space, upward of 20-30 MB/sec but since there's no compression to do the CPU's free to grab as fast as it can go.

As a last resort, you can always use a shot gun as an excuse to get a new PC. ;)

your talking crap

[Lambchop]

thanks people!!
I can't actually try any of those suggestions until after the weekend, but hopefully they should help!!