I need your opinions - on capturing TV in avi or mpeg2

[ktjensen]

FOO,

The ATI TV application will not let me adjust the bit rate dynamically. I can adjust it (sort of) by selecting one of the preconfigured MPEG2 settings, but I usually just pick the smallest resolution for TV (340x280? just guessing as I do not have the application in front of me).


Once that resolution is set, and it is an MPEG2 compression I get what I get. (Wish I could use Vitualdub capture, but something is wrong with that and my ATI card under WIN98se for some reason).


Useing your numbers (4 Megs per second) x (60 seconds per minute) x (60 Minutes per hour) I get 14.4 gigs per hour. So where am I going wrong with my math here? You say 3 hour movie into 6 gigs?

[ktjensen]

FOO,

Again the math question. You say 2 hours per episode with 3 episodes per DVD at 2200 kilibits per second.

That comes out to 47.5 gigs per DVD? But if you subtract 25% due to commercials you get 35 gigs per DVD, but how.

I guess I do not understand this new math. When someone says 2200Kb/sec that is actually the worst case encoding of the video-audio. If the encoder sees something easy to encode the bit rate will drop dynamically down to a very low number?

[FOO]

Video bitrates are specified in BITS per Second
divide by 8 if you want bytes.

I have an ATI AIW Radeon 8500. It lets
you set the resolution and the bitrate.

Not familiar with all the ATI stuff & dunno what you have.
I notice most of the cheaper cards have a limited set of
presets.
Maybe you could get upgraded software from ATI.

Oh well I guess you will have to capture in AVI
and encode. The encoder will let you set whatever bitrate and resolution.
(TMPGenc and CCE) i dunno about the other ones.

[ktjensen]

I have the ATI AIW 7500 Radion AGP board. But I am an amatuer at all this. I went to the http://www.rage3d.com/board/ and looked at the CAPTURE forum. There is a great tutotial by NEVERLIFT on how to do all this. It is very extensive, so I will just need to keep reading and trying different ways to make this all work.

NEVERLIFT mentions that he can get DIVX to work very well at real time compression with 2 hours of video into less than 1 gig of file. Looks real hard to do right. Maybe a grasshopper like me can eventually figure it out. I do not want to upgrade to WINXP yet as I think the file size issue is not the real issue at all.

[tommyoz]

The way you are doing it, capturing to avi with huffy compression and then converting will give the best results.

Just when i thought I was going to make a decision, Craig Tucker comes along. This is actually what I was waiting for someone to say.

Visually it is hard sometimes to determine between AVI and Mpeg2 (DVD). If technically the way mentioned above will give the best results, then I will stick with this.

Thanks

[mgh]

Quality of your drivers for the card is the most important factor-followed by the fact that by the grace of cable service providers, no two channels are ever created equal!
There are too many old wives' tales circulating on this forum-blaming this or that card or software for capture- problem is drivers and the cable service. Unfortunately the manufacturers do not always have the best drivers -this is certainly true for cards based on Bt8x chipsets ( I read somewhere that more than 80 % of the cards being sold have them).
For video capture or encoding there is no universal formula- each video is as individual as us human beings and has to be treated as such. With some TV channels and specific programs - a mpeg2 capture will not need processing-with others it will!!
If your PC has a processor 1 GHz or higher with a 7200 rpm hard disk-you should be able to capture anyway you want-just try out options instead of seeking opinions-there is no short cut!!

[bmiller]

I've captured tv satellite programs to mpeg 2 with my ati aiw,and my ads instant dvd 2.0.I then tried capturing with vdub using the picvideo mjpeg codec,and using tmpge to create an mpeg.The results for me were the avi capture is a sharper picture,and overall better quality.This is what i think i will stick with.I have a "50 widescreen tv and the quality difference shows up more than my old "29 4:3 tv.
To each his own.

[Suds]

You guys seem to be missing a key point, tommyoz is using the WinTV PVR-250 which is a hardware based encoder. I have both the PVR-250 and 8500DV in my rig right now. The quality of the PVR-250 beats the huffyuv to mpeg of the AIW. I am currently using the CDRom release 1.7.21177 from shspvr.com and am getting excellent results doing xSVCD's at 720 x 480 vbr avg 2450 max 3000. I edit in womble, demux in womble and remux in BBMpeg. As an experimeent I did a test cap at dvd of 12000 cbr and reencoded using kwag's latest AVISynth 2.51 optimal script at 704 x 480 to xSVCD using CCE and the result was better than the realtime cap but since I cap several hours a day it just is not worth it for me, at least not with my current setup due to the encoding time.

[snowmoon]

WinTV/bt878(9) owners should check out the post here

https://www.videohelp.com/forum/viewtopic.php?t=169869

Cappting at 720x480 and doing a resize down to 352x480 will produce a sharper image than capping at 352x480 to start. The cards do something intentionally to the image that destroys some of the video resolution. It appears to only happen at <400 pixels wide.

[bmiller]

Tommyoz is capturing video for dvd,so he can capture at much higher bitrates than 2450.I don't think we are missing any points. Capturing at 5000-6000 kb/s,and producing mpeg dvd compliant video and producing ac3 audio during processing is much more computer intensive than xvcd video at max 2450. I know,i've been there.
I have only used one harware encoder,and different software encoders,and my results have shown capturing in avi and rendering with tmpg is far superior than the software,or hardware mpg captures i have done.
To each his own,and whatever you are happy with,stick with it.I'd rather have better quality,at the expense of encoding time any day.Others may not care.

[Suds]

I can only speak for the PVR-250, but if the difference between realtime and encoded caps at SVCD bitrates is barely noticeable then at DVD bitrates I would think it would be even less apparent. Believe me, I am not talking about a comparison of just a few caps but hundreds of them using no filtering, filtering with AVISynth 2.07 and 2.52 with all sorts of combinations of filters at various resolutions using TMPGEnc,CCE and MCE.

[bmiller]

There are too many variables involved for everyone to come to the same conclusion regarding quality and exceptable results.I wish i had the the time to try everything available,but i don't.
Computers,software,hardware,and eyesite,computer monitors,tv's of many sizes and quality.I'm sure there is more.My problem is i'm always trying for better quality.I bought the ads instant dvd 2.0 for the hardware capture only.The software i'll never use.For me i found the mpg capture better than the Ati All in Wonder.Still i find the Avi -Tmpg process gives a better quality picture.Now I have a hardware encoder i'll likely never use again,with about 10 hrs. of use,plus a brand new Ati 7500,of which i only use the s-video and audio inputs.Not a total loss there as i'd need a tv in anyway.Some can aford to keep buying goods just to try out.I can but refuse.
Let your eyes be the judge,as others have also said,but try a few things first.lots of software have trial downloads,so that's easy.The hardware,no that's a different story.