why are divxs bigger than mpg???

[facundosuarez]

Hey there!

I LOVE divx and I have tons of stuff in this format but it has come to my attention that my music video collection is in MPG format since that's how I got it.

The thing is that I want to compress it into divx5 avi with virtualdub and even when I use low bitrate config, I still get an AVI bigger than the original MPG and with less quality of course.

why is this? divx avis are supposed to be much smaller! what am I doing wrong?

eg: Lady marmalade looks perfect as a 40 mb mpg, when compressed I get an awful 60 mb avi

[Awatef]

recompressing to any other format brings *ALWAYS* worse quality, even when you make a 1GB AVI out of a 40MB MPEG!

Keep your MPEGs as is!

For your later encodings, use DivX directly, and then you'll got the quality you want, at the small size you want!

[facundosuarez]

Mhmmm I agree that quality will be worse and it makes sense.

But why on earth do I get video that takes up MORE room in a format that should take LESS than the other?

thx dude

[rmatei]

Obviously, the filesize depends on what settings you use.

You could probably get a smaller file with only slightly worse quality, but it would involve a significant amount of filtering (temp smoother, smart smoother) to remove compression artifacts, and tweaking compression settings.

Also, try Xvid instead of Divx5. It might help.

[facundosuarez]

More examples:

I always encode 2 hr vob film w/divx 600kbps and get a 700 mb file. That is around 5 mb per minute.

Well I just tried to recompress the 13 minute mpg "Thriller" video and got a 200 mb file!!! That is 15 mb per minute.

Why is the recompressed video 3 times bigger than it should? Does it have **anything** to do with the fact that the video was mpg compressed in the past?

thxs and sorry if I am starting to bore u.

[jggimi]

You don't say what tool you're using to do the encoding. If you're using GKnot, and are in the default "Calculate Average Bitrate" mode, it will calculate a bitrate for a file size that defaults to a 700MB CD.

You might also be using Vdub at 100% quality. That too, will create large files.

So ... what are you encoding with, and what values are you setting?

[facundosuarez]

Well I'm using VirtualDub latest version and I tried enconding with

Divx5 1 pass and Divx5 2 passes, always at 500 Kbps.

[Swede]

How about the audio? Since vDub decompresses the mpeg-audio you will end up with raw pcm-audio if you just do a direct stream copy. Make sure you recompress the audio too and I think your filesize will be lower...

[jggimi]

Try using Gordian Knot. Even if you don't use it's automation, it's a terrific calculator. You can use it just for bitrate calculation, or let it process the codec through vdub.

[RadicalEd]

Sounds like what Swede said, unless you're using Vdub to compress the audio then you're getting a 1411 kbps wav file along with your 500 kbps movie :/
Just checked the math and that must be the prob, cuz 15 megs/minute is about 2000 kbps, and what does 500+1411 give us? You can either go with mp3 wav compression in Vdub, normal mp3 and mux it in nandub, vorbis for muxing in oggmux, or aac for muxing in mp4ip. Or you could use realaudio and script an smil to play it, but I still have to experiment with that theory...

[facundosuarez]

OH MY!!!

THANK YOU THANK YOU THANK YOU THANK YOU

I don't know how I hadn't tried reencoding the audio. I thought that mpg stored audio in a rather small format... never thought that the audio was taking up so much room.

and once again
THANK YOU THANK YOU THANK YOU THANK YOU