can someone explain why extracted files are larger?

[mickthetree]

Hi there

I'm trying to get my head around everything and I assume that it is to do with compression, but when I convert a vob file (which is approx 2.5GB in size) to a .MOV file it comes out at about 7.9GB.

I then split the file up in premier and export each section as .AVI files which are anywhere between 2 and 5GB in size each.

So from a DVD with 2.5GB of data I end up with a load of AVI files totaling around 20GB of data!

The only thing I do in premier is split the video up into sections (cuts) and add a title to each section.

I then have to convert the AVI files into flv files which are much smaller (around 450MB for all of them from that one DVD)

As I said, I assume that when I convert the .vob files I essentially uncompressing them? But I dont see why premier is producing such massive files for each edit!

I'm experimenting with avidemux to see if this is any different.

Filmboss mentioned splitting the AVi with avidemux then creating the titles in premier and adding those.

Greatful for any light you can shed on my situation.

Kind regards

[guns1inger]

If you extract the content of a DVD VOB without re-encoding you get an mpg stream (file). What you are doing is encoding (and encoding, and encoding, apparently), which will cost you quality in most cases, and the resulting size is governed entirely by the bitrate you use when you encode.

Obviously when you encode from the VOB format to the MOV format you use a lower compression/higher bitrate than the original mpeg-2 encoding, hence the increase in file size. When you encode from premiere you obviously use a larger bitrate again, hence the second increase in file size.

I am unsure exactly what you are trying to achieve from this process. If it is any (small) consolation though, by using larger bitrates you are most likely minimising the damage you are doing by repeated (and probably unnecessary) encoding.

[mickthetree]

hey guns1inger

Thanks for taking a look.

I need to pull the content off these DVDs (videos of conferences), split them into sections (for each speaker at the conference), add a title to each one then create a flv file for streaming on the web.

I am completely open to suggestions if you know of a better way of doing this. Spent all last week trying to get my head around it.

I am ending up with flv files for example 38minutes at 150MB. The quality isnt great but then again the lights in the conference are low as they use an overhead projector.

[guns1inger]

VideoRedo or Womble MPeg Video Wizard can split your files for you without re-encoding. Womble can even create your titles.

Riva (free) can convert to flv for you.

Much faster and simpler

[mickthetree]

WOW! I've just got a 30 day trial copy of Mpeg video wizard. Cant believe how easy that is!

Exactly what I needed.

I've done a quick test video and thrown it into Flash Video Encoder.

I haven't adjusted the settings yet but the quality already looks better.

I'll post back with my final results, but thanks for pointing me in the right direction!

[olyteddy]

You can also do it in AVIDemux. It opens VOB and can encode the output FLV.

[guns1inger]

You can also do it in AVIDemux. It opens VOB and can encode the output FLV.

If only it had a built-in titler

[olyteddy]

You can also do it in AVIDemux. It opens VOB and can encode the output FLV.

If only it had a built-in titler

Ah yes, missed that...