Capturing high quality and minimum size

[Incubusattax]

I searched the forums for a solution but i didn't find one.
When I capture video with my pinnacle Rave card, the quality isn't optimal but when I convert to xvid with virtualdub I can filter the tv scanlines out. But the problem is that when I capture like 30 min I get a file of approxamitly 1.5 GB. When I compress the file with Xvid, it's still 800 meg. But how is it possible then that people who post Viva La Bam episodes from 25 min or something that are only 200 meg and the quality is great ?

[SaSi]

The trick is in the bitrate.

When capturing, you aim for good quality with high speed. This implies a high bitrate and/or a low compression codec (which is fast), while some people opt for a lossless codec, like hufyuv (100Gb/hour)

Then you do your editing, trimming, etc and then go for high quality low bitrate (low size) compression. Typically this is a two pass process, although it can be achieved in a single pass.

I don't use xVid, so don't know the optimal settings there, but with divx (which is similar in technology and capabilities), encoding for constant quality with a factor of 3.5, I get pretty good quality and small sizes (7~12Mb/min).

Of course, file size is related to frame size (or resolution if you like). A 352 x 288 file encoded with the same quality settings as a 720x576 can have a size difference of 1:4, as the second frame size is 4x the size of the first.

Another trick I see used is to apply a smoothing filter. Smoothing out the video removes high frequency, which is dificult to encode. Some people like the smoothness and view it as high quality (in contrast to artefacts and blockiness). However, a smoothed video can require almost 2/3 of the file size of the same video unsmoothed.

[Incubusattax]

Ow, thx

I captured a movie of 180 minutes now and the size is 8,5 gb. So if i use the divx codec with the settings u said, will I be able to burn it to a 4,7 gb dvd-r ?

I already realised that it's impossible to convert the movie to dvd quality and burn it like a real dvd so I will burn it like an avi and watch it with my divxplayer

[bugster]

Of course, file size is related to frame size (or resolution if you like). A 352 x 288 file encoded with the same quality settings as a 720x576 can have a size difference of 1:4, as the second frame size is 4x the size of the first.

Not strictly true, though I know what you mean.

Actually filesize of any encoded video is related to playing time and bitrate only. Nothing else effects it. However, if you increase the resolution, you need to increase the bitrate by the same proprtion to achieve the same 'quality'. So in that respect it could be said that resolution affect filesize but in truth its the bitrate that matters. You can increase resolution without increasing bitrate and the filesize will stay the same.
Encoding using constant quality techniques means that the encoder chooses the required bitrate for the deired quality and resolution.

Hope this helps.

[Schmendrick]

@Incubusattax:
With any format conversion the picture quality cannot be enhanced beyond the original quality how is was captured, but with the right settings you should be able to retain most of it. There is no problem to convert your movie to a dvd compatible format and then author it as a DVD structure and produce a DVD+/-R/RW which is playable on a standalone DVD player. I am doing it all the time. For this purpose there are enough guidelines and tools on this website (e.g. bbmpeg+IfoEdit).

CU

Schmendrick

[flaninacupboard]

Ow, thx

I captured a movie of 180 minutes now and the size is 8,5 gb. So if i use the divx codec with the settings u said, will I be able to burn it to a 4,7 gb dvd-r ?

I already realised that it's impossible to convert the movie to dvd quality and burn it like a real dvd so I will burn it like an avi and watch it with my divxplayer

You could either do a Divx with 192kbps audio and 3221kbps video for 3 hours to fill a DVD-r, or you could do a Half D1 mpeg file (352x480) at the same bitrates. both will produce very good quality, the Divx would be superior. obviously only works on a Divx player though, wheras half D1 is part of the DVD spec, so will work in any player.

Final alternative, do two DVD-rs with full resolution and 6mbps video, this will be the best quality option.

[Incubusattax]

mmmm, the purpose was to create a dvd from the avi.
But I realise that it isn't possible to maintain good quality if you want to burn it onto a DVD and play it in a dvd-player.

But what bothers me is that when I capture the video, is that the filesize is very large. I use the Pinnacle Wave Software that has been delivered with the card. Are there maybe any other appz that do the same but give a lower filesize ?

I tried compressing the movie with Virtualdub and I added a smoothing filter. But when I put the smoother on 25, my subs are all messed up. So I used a 5 setting. But that doesn't give much difference from the original. I also added a deinterlace filter. I started encoding and the filesize was even bigger ! Is that because I'm aplying those filters ?

But I was also thinking, maybe I should add a sort of image that covers the subs and then I can put the smooth settings on 25 and I'll just download some *.srt subs and compile them into my vob file. Isn't that better ?

[flaninacupboard]

you've no need to muck around with smoothing filters or recompressing your .avi to another .avi.

Just make a DVD using 352x480, with video at 3200kbps VBR and audio at 192kbps - i promise you this will look very nice and still fit on a single, fully compliant, DVD-R. just try a quick test encode.

[Incubusattax]

Should I use TMPGEnc for that or what ?
Which is the best program u think ?

[flaninacupboard]

yep, tmpgenc will do nicely. hasn't let me down yet