Compression Questions?

[dsenart]

I just got my first Camcorder. It's a canon elura 40 mini DV. I have figured out how to transfer still images to my computer as well as video from the tape that i record to. Here is what I am looking for help on.

When I downloaded a 4 minute video onto my computer it is taking up about 250mb's of information. It is in MPeg format. I used Divio to try and download from the camera straight into .avi format and the same exact file was nearly 1 full gig!!!

When I am downloading movies from kazaa or tmd etc.. these file are in .avi format but are MUCH MUCH smaller then what I just did for 4 minutes? What are these people doing to compress their videos?

I have vcd's of 2 hour movies that fit on to 2 cd's. Now if i have 2 hours of home film footage I would like to be able to put them onto vcd or dvd format so that I can enjoy them with other family members that have players to play these. Can someone direct me please?

Thanks

DSenart

[dsenart]

nobody knows how this works?

[ImaWeTodd]

People may have not responded because you want to make VCDs but you have a limited understanding of some key items. Try explaining baseball to someone who has never seen a game.

It's all about compression. Look to the top left of this page under what is VCD and scroll to the bottom for the comparison chart. See the compression line. Read about compression types.

An AVI file can hold many types of compressed (or uncompressed data). The ones from the internet are compressed alot. Uncompressed AVI data probably takes up 720x480x30x60 bytes a minute. That would be the frame rate of 30fps times the frame size. I may be a bit off, but you get the idea. 622080000 is a lot of bytes. DV (what a miniDV camcorder uses) is compressed 5:1.

To learn about these things I would suggest you look up things like AVI, DV, Compression, Conversion, in the glossary.

To put your dv on a VCD you can follow guides under capture and convert.

Hope this points you in the right direction.

[FulciLives]

When you use the FireWire port (IEEE 1394 or iLink as SONY calls it) then you are transferring the digital A/V from your DV cam to your computer in the DV AVI format. This takes up a lot of space. But if you need to do any editing then this is the way to do it.

Anyways, after you copy your video to the computer you can then convert that DV AVI file into whatever you want. You can convert it to DivX or Xvid (such as many "downloadable" files you find) or you can do mpeg-1 VCD or mpeg-2 SVCD or DVD.

Please note however that VCD has very poor resolution and a very low bitrate which adds up to a very unpleasing image.

You should really consider either doing SVCD or getting a DVD burner.

I doubt you will be happy with VCD quality as it will look like CRAPOLA compared to the original DV footage.

- John "FulciLives" Coleman

[ktnwin]

dsenart,
OK you want to transfer your DV tape to computer and make DVD, right ?
There are a few software out there (fairly cheap) that can do the job and save you the hassle of learning. Although it's fun to learn what's involved in making DVD from video tapes (analog and/or DV).
To start with, I suggest you to buy one of those software. The one I recommend for newbee: neoDVD (50$ max).

[dsenart]

I actually have a dvd burner. I am sorry if my questions seem stupid or irrelevant. I am not necessarly trying to put the files onto VCD. If i can find easy softare to use to convert the file to svcd, or dvd then thats what I will use. Right now the only software I have is AVI2VCD then I through the output file into Nero and go.. I can do that with movies I download no problem But the file size of the movies I am downloading are 250mb for the entire file, my 4 minute video taken around my house was this by itself.

So if I understand this right I need to put my video files onto my computer ( it is a large mpeg file ), then I need to encode that to divx to compress the file? If this is so can anyone suggest really easy software to use, or possibly some freeware that can do this

After it is compressed to divx mpeg then I need to encode the files to the video format that I want to use to see the movie ie.. VCD, SVCD, DVD etc.. correct?


So I am having to encode the file twice to get the correct format.

If this is right then I just need to find easy to use software to do this.

[ktnwin]

dsenart,
if you read my post carefully, you will see the process is much simpler than you describe: the file is only encoded ONCE, not twice, and Divx format is not even in this picture.
1) neoDVD will capture either in DV AVI or MPEG-2 (for DVD)
2) neoDVD can import either this DV AVI file or the MPEG-2 file, create menu, chapter points and author / burn DVD
All in one software, there is no Divx or other software to worry about.
Amazingly simple.
I would recommend this to newbie that likes to make DVD the first time. Once you become proficient, then start looking at different software.

[ImaWeTodd]

I didn't really understand your need. I made a dvd from my miniDV cam just the other day. It took about 20min of sitting at the PC time. I will not mention the Software I use because there a many ways to do this and probably many all in 1 packages. I did want to clearify the process.

1) miniDV captures video in DV compression format (big file high quality)
2) Transfer to PC using firewire keeps the DV format
3) You may want to edit out the lense cap sceens
4) Encode (recompress) the video into MPEG2 & maybe compress the sound but probably not. This would be a much smaller file
5) Author the DVD (which basically makes file structure for a DVD, using the mpeg2 file(s))

[pijetro]

To answer your original question, chances are, that the movies from Kazaa are in Divx format....

BASIC overview:

There's two "families" of video. One family is .AVI (audio video interleave), and the other family is MPEG (motion pictures experts group).
The .AVI family is "old school" video for computers. Within that family, you have fat and skinny relatives (ie compression ratios)..Huffy,Divx, Xvid, DV, and a bunch of others belong to that family, with each one having different compression ratios, and properties. In your case DV is what gets transfered into your computer. Divx, for example gives great quality, with a small bandwidth (great for sending over the wires).

The other family is .MPG. This is a compression in it's own right, but for simplicity, let's just say it's the neighbours down the road..... The two main .mpg members are Mpeg1 (for VCD's), and MPEG2 (SVCD and DVDs).

What comes off your tape is DV, and yes, the files get big in size. 15gig an hour or so. But that being said, it's the easiest to edit and keeps quality the best in its native format...
That being said, you have to ask yourself "what the heck do I wanna do??".
1) Compress to Divx??(only good on computers)
2)Burn to DVD (transform your video into MPEG, thus changing the structure of the video)..

What might be confusing is the fact that some softwares allow you to capture, and convert to .MPG on the fly, thus saving you disk space. If the MPEG is DVD compliant, then burn to disk. As you learn more, you'll be chasing down better quality...

And NO, don't compress to Divx, then back to .MPG. You'll lose quality. The shortest path gives the best results. The most popular software to work your DV .AVI file is Virtual Dub. The most popular software for converting to .MPG is Tmpgenc..

You've got a lot of reading to choose from on the left hand side.........

Good luck....