how do you get avi's down in size but retain quality. i cannot do it at all

[buachille]

this is my first post on this forum. i just found it yesterday and i'm hoping to have a few questions answered that so far i have not found a solution to. i've searched google for decent video editing forums for a while now, but never found one that seems to be so as in depth as this, so here's hoping....................
I have quite a few similar video clips (avi compressed with xvid) and i notice that although they are 40 minutes long the file size is only (per show) 350 meg.

if i tried to compress a 40 minute video using virtual dub or adobe premiere elements (these are the 2 programs i currently use for my video stuff) it would be huge - nowhere near 350 meg. or if i set up the programs (or codecs) to compress it that much i imagine i'd get terrible quality.

so, how is it done. how can i get that lengh of video down to that size.

by the way, i currently have divx, xvid, indeo, intel, etc, codecs installed. there are more but i think i've mentioned the most important.

any help will be much appreciated. thanks

[kschang]

Learn to use a bitrate calculator. Basically, higher the bitrate, the better the video, but bigger the size. Also set 2-pass VBR, and trellis, and extreme optimization... And you'll get decent quality. Heck, I've seen decent 1.5 hour movies squashed down to 700 megs.

[buachille]

ok. i'll have a look for a bitrate calculator then. i don't have time to check now but i'm sure there will be some listed on this site.

i've seen that 2 pass thing before now you mention it.

thanks for your reply.

[guns1inger]

vcalc covers everything from DVD through to avi files, and is small, self-contained and free.

[FulciLives]

Also there is the videohelp.com bitrate calculator:

https://www.videohelp.com/calc

- John "FulciLives" Coleman

[Nelson37]

Many factors influence quality attainable at a particular size. Xvid or H.264 will give the best compression, with limited playability. Lower resolution, obtained by resizing or cropping, gives fewer pixels to encode. De-interlacing also yields fewer pixels, as well as eliminating artifacts and makes for a less complex problem for the encoder to solve. Multi-pass encoding gives a major quality benefit. Lack of noise in source and/or smoothing filters will give a smaller size, though smoothing will sacrifice an amount of detail.

There are positives and negatives with almost all "solutions" to the basic problem of compression. None are perfect. Start with the best possible source, and encode with the best possible methods, to get the best possible result.

[buachille]

Learn to use a bitrate calculator. Basically, higher the bitrate, the better the video, but bigger the size. Also set 2-pass VBR, and trellis, and extreme optimization... And you'll get decent quality. Heck, I've seen decent 1.5 hour movies squashed down to 700 megs. smile.gif

right i learned to use the bitrate calculator (video calc), which took all of 1 minute. i see how this is useful but it does not really tell me how i can get a 40 minute video down to 350 meg.

is the magic in the 2 pass variable bitrate selection (does virtual dub do this or would i do this in abobe premiere elements?).

what is trellis?

what is extreme optimization? i haven't seen that setting / option yet.

vcalc covers everything from DVD through to avi files, and is small, self-contained and free.

thanks, i have it now and it is nice and easy to use.

[naselloj]

Hello buachille Can you please tell me how you do it and what programmes you use
I have been looking for how to do this a long time.
Thanks

[buachille]

Hello buachille Can you please tell me how you do it and what programmes you use
I have been looking for how to do this a long time.
Thanks

hang on a minute. you have me confused. i thought i was the one asking how to do it.

what exactly are you asking me. if i know i will help you.

[kschang]

Maybe he means when you find out.

Sorry for the confusion earlier. Those features are found on X --> MPEG2 encoders, such as QuEnc and so on. As you just want to compress to AVI you'll probably NOT see that sort of options.

Are you working off of a DVD? Have you tried AutoGK, or its brother, Gordian Knot, both of which encodes DVD's into 700 (or some other sizes) of AVI file at optimum quality?

[buachille]

no. these are files on my pc.

the thing that is behind this question is this: i have lots of films that i've made of my family. i edit them in adobe premiere elements and then save them as avi (as i never seem to get decent quality in any other format). so they are all now sitting my hard drive and taking up quite a bit of room and i'd like to shrink them down.

i've been given videos by other people which are 40 minutes long and are only 350 meg each. my home videos are much bigger. i think if i make a 20 minute video and save it as avi it will probably be about 2 gig in size.

[kschang]

Basically, we're going to re-encode. Use GSpot on your existing AVIs and see what codecs they use. If they don't use XVID, DVIX, or similar codecs, then they can be reencoded.

However, I personally would just buy a DVD burner and dump those files to DVD (2 copies each) and store them in different places. Every time you re-encode, you lose quality (even if it's not as perceptible to human eye).

[naselloj]

Sorry buachille with what you wrote (thanks, i have it now and it is nice and easy to use. ), I thought you figured it out
I'll keep looking and if I find out how it is done, that is make a 40 minute movie into a 350 meg avi I'll post my findings here
for you.

[buachille]

Sorry buachille with what you wrote (thanks, i have it now and it is nice and easy to use. ), I thought you figured it out
I'll keep looking and if I find out how it is done, that is make a 40 minute movie into a 350 meg avi I'll post my findings here
for you.

now i see why you were asking me that question.

anyway, i think what we will both have to do is start experimenting. that is normally how i figure out how to do computer stuff, but the problem with experimenting with video is it takes so incredibly long to see the results.

so good luck to you and to me

[buachille]

Learn to use a bitrate calculator. Basically, higher the bitrate, the better the video, but bigger the size. Also set 2-pass VBR, and trellis, and extreme optimization... And you'll get decent quality. Heck, I've seen decent 1.5 hour movies squashed down to 700 megs. smile.gif

kschang, if you have some spare time would you possibly (please please please) tell me how exaclty you would go about reducing a 1.5 hour movie to 700 meg.

what software would you use.

apparently you would use 2 pass vbr,trellis, and extreme optimization (although i think i read in this thread that they don't apply to avi's).

what would be the steps you would go through?

cheers

[kschang]

To ReEncode AVI, (or any sort of file, for that matter), you have to play with the encoder options. For now, I'm going to assume you're going to use XVID codec, as it's easily available, free, and produce good results. And use VDubMod to do it.

Open VDubMod, and open your AVI file.

Go under Video, and compression. (Oh, and make sure you have Full Processing selected) If you have XVID installed, it'd be at the bottom of the list. Go ahead and pick Configure. Use the calculator to play with the size and desired bitrate. (Yes, yet ANOTHER bitrate calc!) That sets your video options.

Go under Streams, and pick Stream List. Right-click the choice and you'll get a nice menu. Make sure you pick "Full Processing". If you don't, you don't get the nifty options. That sets your audio options. Right click, pick compression, and make sure MP3, CBR is selected at your desired bitrate.

File / Save As... and pick an output name. Run through a segment and see how you like the quality.

NOTE: For the first run, just do a 1-pass and see how you like the results. 2-pass will take MUCH longer but you may not notice the difference.

[Nelson37]

Have you tried reading some of the guides in the HOW TO section? Lots of methods, step-by-step instructions, pictures, and everything.

Any answer you will be given here will just leave you with more questions. You need to do some reading in order to learn the basics.

Essentially, you must first decide what format you want to finally achieve, which will be dictated by your desired media and playback hardware.

ANY compression will lose some quality. The question is how much you are willing to lose in order to save space, and then how to minimize the loss. You cannot eliminate it completely.

I basically answered your question earlier, which parts did you fail to understand?

[buachille]

nelson37,

you are right (i'd not read the how to's). i broke all the rules of forum posting here. i started this thread (in desperation) before reading all the stuff that is already on the site (and there is lots).

since i made the post that you've just replied to i've been doing quite a bit of reading on this site and i'm already starting to grasp a couple of basic concepts.

i've also tried converting a couple of my avi's to xvid and divx avi's but i just got totally abortive results, so i must have done something very wrong. i'm now trying gordian knot which someone pointed me towards earlier and its encoding now so we'll see what happens with that.

i agree that you answered my questions earlier and i understood your response, but it is the nitty gritty of working with these basic facts that i now need to learn, and which i will learn by reading all the info on this site.

thanks for all the replies everyone. hopefully i'll get a bit better at this soon.