zipped video file still massive

  Grambo 19:46 17 Jan 03
Locked
  Grambo 19:46 17 Jan 03

I have brought a l'espion digital camera which has an AVI function. 80 rapid shots which lasts about 6 seconds. Unzipped file size is 5.9 Mb and zipped still 4.8. This is obviously too large for email attatchment. My brother sends longer vids (plus sound in his case). I am using the standard zip on XP. How can I shrink file even smaller

  Gemma 20:06 17 Jan 03

File compression depends, inter alia, on the fact that many data files contain a lot of "white space" in long runs or the same byte (8 bits)repeated many times in a string.

So a compression program sees a long repeated string and replaces it with something that says, for example, 2,000 spaces follow from here. It takes maybe 8 bytes to say that so saving 1,992.

De-compressing just reverses the process.

Video and sound files start by being very "dense" because the designers knew they would be big and went to great efforts to keep them as small as possible. They are effectively pre-compressed so don't respond too well to the technique.

Sorry about the trivial example and vast simplification but that's the flavour of it.

  Scouse 20:54 17 Jan 03

Grambo, sorry I can't help with the compression but having read the thread I must say that Gemma, no need to apologise for the "trivial example". The explanation has just helped my son answer a question with his homework. His I.T. Exams are not that far away and your explanation is a vast improvement on mine!!

Cheers

  Grambo 01:23 18 Jan 03

I think the problem I have here with my very relatively cheap camera (you can fit it in a matchbox almost, only got it for a bit of fun) is that this AVI is literally 80 (low quality)pics strung together. Nothing like the mpegs ive been recieving which are 500 kb as opposed to the 5Mb my camera would use up. Dont spose there would be a 'save as' to get round this. As you can tell Im a bit of a novice with the video files so bear with me
Thanks

  spruce 04:48 18 Jan 03

Try using some utilities that convert the AVI file
to MPEG. A excellent free download is moviexone;

click here

or use something like mgi videowave

The trouble with compressed files is the inability to alter compression rates due to the algorithm used. It is sometimes best to change the format of the file itself and then attempt a compression.

  rsturbo 05:04 18 Jan 03
  spruce 05:14 18 Jan 03

Those small cheap cameras are fun to use, but are you sure it is recorded in AVI format.

I am aware that you can take up to 80 photos at high resolution and that each photo is counted as a single entity in .bmp format. It may be worth checking that you are definately recording in AVI format (which I think it does when it is connected to your pc as a webcam).

  crx16 05:49 18 Jan 03

import the file into 'windows movie maker' then just 'save movie' export as WMA and get a choice of quality/compressions,can get upto 5 times smaller than AVI and still watchable.

  Grambo 17:44 18 Jan 03

Thanks all, but before i decide which road to go down I would like to know more about the windows movie maker. Ive looked at standard progs on machine so I assume this is a download

  crx16 18:01 18 Jan 03

start\programs\accessories\windows movie maker. you should have it

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