Question about resolution settings in ATI's MMC

[payton34]

Good day,

I am capturing VHS with my ATI all in wonder card. In the settings dialog box for the ATI's "Multi Media Center", I select AVI, and then whatever codec I choose.

Why does it allow me to capture in various resolutions but only up to a max resolution of 704x480?

If I select MPEG2 rather than AVI it will then allow me to capture in the full 720x480 resolution.

Thanks

[Nelson37]

You can lose your mind trying to figure out WHY the MMC program does certain things in certain ways. Lots of them make no sense. It is what it is.

I once made several dozen test captures, incrementally changing different settings to check their effect, only to find out at the tail end that it was decreasing the motion sensitivity by 1 with each edit, thus invalidating all my test results!!!

Some recent experiments indicate that for DVD playback, there is no effective difference between 704 and 720.

[payton34]

Nelson37,

Thanks for the reply. Now I seem to have even a bigger problem. Every capture I have made so far has a glaring fault. On all vertical lines that are in motion there are teeth of a comb or line like artifacts. This happens when I capture broadcast off my cable to AVI or MPEG2, and it also happens when I capture MPEG2 or AVI from my SVHS VCR. The capture card will play any clip on my computer monitor fine. The error only shows up when I record and try to play the clip back.

I also have tried an MPEG 2 and AVI capture as well, and burned to DVD and the video still displayed that comb effect when I played the clip on a TV. I tried every combination of settings as well as to make sure I was capturing interlaced and nothing works.

I called ATI and got elevated to level 2 support and they were completley useless.

Oh well, at least I still have another two weeks left to return the card where I purchased it.

I have installed the latest drivers and MMC software and still the problem exists. I have a pretty powerful PC.

If anybody has any ideas before I return the card I am willing to try anything. The card works great other than for capturing.



Thanks

[DRfrankenpimp]

i captured interlaced mpeg 2 froim my ati card 720 by 480 authored it to dvd and got a similar problem i think has to do with top or bottom field first so i captured deinterlaced and it played ok if i reencode and deinterlaced it played ok. try restream also, it might help.

[junkmalle]

Every capture I have made so far has a glaring fault. On all vertical lines that are in motion there are teeth of a comb or line like artifacts.

It's not a fault, it's normal. Since you're already looking at digitalfaq.com:

http://www.digitalfaq.com/dvdguides/capture/understandsource.htm#interlace

Do not deinterlace except as a last resort. If you burn your video to DVD with the proper field order (source and destination) it will play back fine. On the computer use a player that deinterlaces on-the-fly while playing.

Capture at 720x480 or 704x480. Do not crop the frame. Do not resize the frame. Doing either of those is likely to destroy the relationship of the two fields. Make sure the DVD software identifies the source field order correctly.

What software are you using to burn to DVD?

[payton34]

I am for right now using Pinnalcle 9 plus. I just started to experiment with NERO. In NERO, HUFFYUV shows up on the drop down menu as one of the available codecs. In NERO, PCM is one of the audio options for capture, however the configure button is greyed out. I do not know if it is sampling the audio at 44hz or 48hz or at what bit depth.

It seems to work fine and regconizes my ATI all in wonder card. I am still confused as to why in the ATI MMC software it will only allow 704X480 resolution, but in the NERO software it allows the full 720X480 resolution.
Except in NERO I cannot seem to access my audio settings.

[junkmalle]

It seems to work fine and regconizes my ATI all in wonder card. I am still confused as to why in the ATI MMC software it will only allow 704X480 resolution...

Why is it so important to capture at 720x480? 704x480 is perfectly legal for DVD too.

[payton34]

I am just more curious than anything as to why MMC won't allow 720x480 capture. Would the image quality in theory be better at 720 verses 704?

In practice It probably does not matter.

Any idea why NERO won't allow me to select any parameters in PCM mode?

Is it possible that when the settings box is greyed out, their PCM defaults to the best quality settings ie 16 bit 48hz?

[anitract]

payton34, I've not noticed any better quality @ 720. 704, being the native resolution of the card, seems to work just fine for me. Lots of people like 352.

[edDV]

payton34, I've not noticed any better quality @ 720. 704, being the native resolution of the card, seems to work just fine for me. Lots of people like 352.

704x480 is the ATSC SDTV broadcast spec. Note that 2x352=704.

720x480 is the transmission spec. The extra left and right pixels are there to allow for h-phase (horizontal position) errors without edge clipping. It is not a picture quality issue.

[payton34]

ahh...my mentor is back from his well deserved vacation from the videohelp forums.

Thanks everyone, the info has made it clear to me.
BTW the "digitalfaq" site got back to me today, all is good.

While we our on this subject of quality captures with ATI cards or similar devices.

Some specs that I have never seen printed anywhere pertaining to ATi or other capture cards is just exactly at what specs are the cards converting analog to digital.

Another words, one could use a very high quality lossless codec such as HUFFYUV with 50 gig file sizes per hour of video.......

but, none of that matters if the card you are using does not deliver a high quality analog to digital conversion for your lossless codec to compress.

Would the three following criteria pertaining to capture cards be important to their ability to perform high quality conversions of analog to digital:

1 At what bit depth does the capture card convert with, 8 bit 10 bit 12 bit etc.?

2 How many times per second does the card sample the data?

3 What is the ratio of how it samples the luminence and chromiance, ie 4:1:1, 4:2:2 or 4:4:4 etc.

With the above in mind are most capture cards in the $600.00 or less range pretty much equal? Do they all have the same specs?


Thanks

[edDV]

Would the three following criteria pertaining to capture cards be important to their ability to perform high quality conversions of analog to digital:

1 At what bit depth does the capture card convert with, 8 bit 10 bit 12 bit etc.?

All consumer level and many pro level cards quantize to 8 bits (256 levels). Of these 256 gray levels, the CCIR-601 (ITU-R BT.601) specifies black at level 16 and white at 235 for the Y channel. These are the levels used in both pro and consumer 8 bit equipment including DV, DVD MPeg2 and ATSC digital television.

ITU-R BT.601 parallel and SMPTE 259M serial equipment (aka SDI) can also use 9 or 10 bits for greater gray scale resolution transfer. For 10 bits, black is defined at level 64 and white at 940. Super pro production equipment (e.g. Digital Betacam, HDCAM SR) use 10bit to prevent rounding errors as the signal passes through various steps of the production process. Internally, equipment can operate at 12bit or higher quantizations.

As with SDTV, HDTV can use 8 bit or 10 bit quantization during production. The HD broadcast and HD DVD specs are 8 bit and also use 16-235 levels.

2 How many times per second does the card sample the data?

13.5M samples per second for Y. This is the "4" in 4:1:1, 4:2:2 and 4:4:4. Nyquist theory implies a 13.5 MS/s sample rate can capture the equivalent of 6.75 MHz (540 lines*) analog video bandwidth if a perfect low pass filter is used. Real world low pass filters will limit analog capture bandwidth to a lower number.

3 What is the ratio of how it samples the luminence and chromiance, ie 4:1:1, 4:2:2 or 4:4:4 etc.

"4" = 13.5 MS/s
"2" = 06.75 MS/s
"1" = 03.375 MS/s

With the above in mind are most capture cards in the $600.00 or less range pretty much equal? Do they all have the same specs?

They are all using similar cheap parts to allow >$600 or even >$100 pricing. Pro cards use more sophisticated A/D, low pass filters and analog conditioning stages.

* For analog video "lines" refers to the ability of the eye to resolve alternate black and white lines on a resolution chart. This is different than image pixel resolution which is 704x480 (704x576 for PAL) for SDTV.

[anitract]

704x480 is the ATSC SDTV broadcast spec. Note that 2x352=704.

720x480 is the transmission spec. The extra left and right pixels are there to allow for h-phase (horizontal position) errors without edge clipping. It is not a picture quality issue.

hey edDV, can you rephrase that for me (in simple terms)? I'm not sure what you are getting at...are you saying that 720 is just 704, but with added pixels to stop certain errors?

[junkmalle]

Most cards have a "native" capture resolution and any other size is produced by resizing what's captured. You will not find any manufacturer advertising the native resolution. You might find it in the data sheets for the capture chip.

There's no way of predicting how a capture card (or more precisely its driver) is going to resize from its native resolution to the specified output resolution. With your example of 704 to 720 it may stretch the 704 out to 720 (with any number of resizing algorithms) or it may simply add a total of 16 black pixels to the two edges.

[edDV]

...
I'm not sure what you are getting at...are you saying that 720 is just 704, but with added pixels to stop certain errors?

yes.

[Tom Saurus]

I am glad this topic was brought up. I have my ATI MMC set at the Full DVD Setting 720x480. For some reason I don't have the option of 704x480; I have always thought perhaps that would be the better setting. This has set my mind about that issue. I am quite pleased with how my All In Wonder 9800 Pro captures video and audio.

[lordsmurf]

I I have my ATI MMC set at the Full DVD Setting 720x480.

If you're using ATI MMC default settings, you are deinterlacing, and you are losing a lot of quality. Visit www.digitalFAQ.com and follow those guides.

[Tom Saurus]

Lordsmurf: I appologize I should of explained myself better. I did read several articles at your website and followed your directions on the settings to capture mpeg with the MMC Software. The only difference is that I chose 720x480 instead of 352x480 and you instructed. The resulting video and audio is excellent and I am quite pleased with it. Thank you very much for the Guides at your website, I have learned alot from them.

[lordsmurf]

Ah, makes sense.
The ability to use 704x480 also depends on the MMC version.