re-encoding Divx for a smaller size

[Draco]

What's the best way to shrink a Divx movie to get it to a smaller size? I currently have about 6 movies that are each about 1.2 gigs big. I'd like to shrink them down to a point where I can get them on a single CD.

The easiest way I could figure out would be to use a ratio of [desired file size] / [current file size] = [desired video bitrate] / [current video bitrate]. The problem with that is that I don't know what the current video bitrate is, so I can't figure out what the desired video bitrate should be. (I know that's probably not the most accurate way to determine it, but considering that the large majority of data is video, I figured it was close enough). I don't to take a guess at it, because the resulting file might be too big or too small, which would waste about 8 hours of my time.

What's the best way to do this? If the above ratio would work, how can I find out the current video bitrate?

Thanks. BTW, new to the group, but I've been reading this site for a good while.

Draco

[Fruitmaker]

get a bitrate calculater...
that will tell you, what you have to do

download @digital-digest.com

have fun

[techno]

Hi there, since I have broken the world record by compressing videos alot and producing high quality (4 mins = 12MB-15MB the way I do it) :

make sure audio is MP3 with 128/164kb/s

video should be DIVX 3.11alpha fast motion 20/25 keyframes,
75crisp or 65 and bitrate = 6000kbps

and use virtual dub to do this. I hope this helps, email me and let me know how you get on.

Techno :cool:

[UncasMS]

techno, noone (except some lamers at TOMS) will suggest using FAST motion. it is crap!

have a look at any proper guide or even better make some tet yourself and it will become obvious, that fast motion will give you a file that might fit on one cd, but thats not at all quality you'll get with fast motion!

[techno]

I think I should know because I have broken the world record on compressing videos alot and high quality (4 mins = 12MB, 1 hour = 400MB if I do it my way)

So there

[UncasMS]

ooooohhhh -- ok that of course makes a difference!

well then, share your secrets with us and most important: show us some proof!

[Draco]

Well, these weren't exactly the answers I was expecting, so either I didn't make the post clear or I'm not understanding something.

The videos are already compressed, converted, etc, using Divx (Low Motion, I believe). They are each about 1.2 gigs in size. I'd like to shrink them down to about 650 megs.

I was guessing that VirtualDub would compress something that was already compressed. In other words, it'd take the Divx movie, and use Divx again to re-encode it with a different video bitrate. Therefore, I'd need to know the current video bitrate. Sorta like zipping a zip file.

Can I assume that the current bitrate means nothing to VirtualDub, and I can just re-encode it as if it was encoding the original VOB files?

I guess relating to this, a friend of mine asked me something about VirtualDub that I couldn't answer. Maybe somebody here can help. Say you've got a Divx avi file. You run it thru VirtualDub to do some editing, etc, then Save As AVI using Divx. Does that degrade the video quality any more, since it's been encoded/compressed twice? Reasons why or why not would be helpful also.

Draco

[Randir]

You don't need the VidBitrate in order to encode to a lower one. Just use the Bitrate-Calculator, like mentioned above.

When you just edit an avi-file with VirtualDub you don't need to encode it again. Just select Direct Stream Copy in Video-Options.

[techno]

That's right Randir (sorry if I spelt your name wrong) but I was just trying to give information from my own experience. You are right, no harm done is there? I use 6000 bitrate on fast motion and 3.11 VKI(scene detect patch) cause of quality.

Thanks

[Randir]

sorry, but wasn't talking to you.
i was referring to the original question

[techno]

Sorry SIR Randir, I do aplogise, Please forgive me.

:)

[Randir]

maybe i will, if you stop being such a pita

you're not funny :smashead:

[UncasMS]

hi guys,

pls try to see it this way:

from my p-o-v techno did NOT use sir to make fun of anyone, therefore, it might be a simple misunderstanding!?

[Randir]

I am willing to see it from your point of view.

Sorry for causing trouble.

[UncasMS]

you didnt - as nobody else did;)

thanx anyway

[Draco]

Wow. Who could've thought that one little question could have gotten this kind of response :D

But thanks for clearing everything up. Makes everything a lot simpler.

Draco

[UncasMS]

exchanging ideas and a dispute every now and then should be possible on a board like this ;)


stay alive and kicking, guys!!:angelgrin

[khitch12]

Regarding draco's question, you will definately need to reprocess the video if you do anything to it in virtual dub but you will find that out. Yes the quality will suffer. Like making a xerox of a xerox. Nice thing about vd is that you can just make a clip with it and see if thats what you really want to do. Lot better then reprossessing the whole movie to find out that you don't like it that way. Certainly of course leave the sound set at direct stream.