Why so big... #2

[ATJ]

Following on from the problems JustSomeGuy was having, I too am having problems doing conversions - but I only want to do a 5 minute clip.

I want to take 5 minutes out of a 30 minute program I recorded from the TV. For some reason most ripping tools (Chopper XP, Nero and DVD Media factory) will only let me read the first few seconds of the VOB files off the DVD. To get around this, I use Nero Recode 2 (which does read the VOB files) to convert the 5 minute clip I want to Nero Digital ("MP4").

I have then used Nero Vision Express to read the MP4 file and export it to MPEG-1. However, no matter what bitrate, frame size, compression, I use, the resulting MPG file is always 50 MB give or take a couple of hundred bytes.

I even took one of the output MPG files of 50 MB and imported it in to ULEAD VideoStudio 7 and exported it to MPEG-1 and it too was 50 MB.

What gives? Shouldn't changing the bitrate or the frame size change the size of the output file?

[mats.hogberg]

What gives? Shouldn't changing the bitrate or the frame size change the size of the output file?

Changing the bit rate will, changing the frame size wont.

/Mats

[ATJ]

Why won't changing the frame size change the size of the output file? Doesn't a larger frame have more information to store? If the frame is 720 x 576, that'll be 414,720 pixels per frame. If the frame is 352 x 288 it will only be 101, 376. That's a quarter of the information that has to be stored - ignoring compression, of course.

Anyway, it still doesn't solve my problem as I WAS varying the bitrate and the output file size was still 50 MB.

[mats.hogberg]

Why won't changing the frame size change the size of the output file? Doesn't a larger frame have more information to store? If the frame is 720 x 576, that'll be 414,720 pixels per frame. If the frame is 352 x 288 it will only be 101, 376.

Because the bit rate is The Bit Rate.
Let's say the bit rate is 2000 kbps. Each second 2 megabit, or roughly 250 kB is read from the file when playing back. If it's a PAL movie, (25 fps) each frame gets 10 kB. No matter the size (resolution) of the frame, this is what it gets. A high res pic (SVCD, DVD) needs heavy compression to "fit" into this 10 k, while a low res (VCD) doesn't need the same amount of compression.
As you say, however this doesn't explain your situation. I'm not familiar with any of the applications you mention.
It's not clear what you are trying to achieve - what's your source, and what do you want to do with it?

/Mats

[ATJ]

It's all in my first post. I want to take a 5 minute clip and make it smaller than 50MB.

[mats.hogberg]

That's not very clear (at least not to me). "Clip" can be just about anything. Is it AVI? Is it mpeg? In what flavor? How long (in time) is it?
Smaller doesn't say much either. What do you want? Convert it to mpeg1? mpeg2? AVI? How big is acceptable?

/Mats

[ATJ]

I have a 30 minute recording on a DVD. It was recorded on a Panasonic DMR-E50 in XP (High-quality) mode. I guess it takes up about half the DVD.

I want to take 5 minutes out of the DVD recording and make into an MPEG-1 file. I have already done this, but the file is 50MB and I want to make it smaller - so that it doesn't take forever for people to download. I guess 10MB would be acceptable, but I'd have to see what that does with the quality. However, no matter what I change, including the bitrate, it always comes out at 50MB.

[mats.hogberg]

OK, then I'd demux the vob to video mpeg2 and audio (wav or mp2) (Use ReJig). Load them into TMPGEnc (you'll need the mpeg2 plugin for tmpgenc), use the source range to select just the 5 min you want, set the bit rate to whatever you want (5 min at 10 MB is about 1800 kbps from the top of my head Edit: My head wasn't connected! 5 mins at 10 MB is about 270 kbps - Way too low for anything! /Edit - way too low for DVD res, so resize to 352x576 max) and encode.

/Mats

[ATJ]

As per my original post:

For some reason most ripping tools (Chopper XP, Nero and DVD Media factory) will only let me read the first few seconds of the VOB files off the DVD.

None of the tools I have tried so far (except fot Nero Recode) are able to read the VOB files. I'll give ReJig a go, but if it is like the others...

[bugster]

5 mins = 50Mb at VCD bitrate.

How are you creating the mpeg-1, are you selecting a VCD template in Tmpgenc or Ulead?

If so, you must select it to be non-standard. In TmpGenc this is set on the system tab. If you do not then the bitrate will be padded to the VCD standard. I would guess Ulead is the same.

A word of warning. Some versions of TmpGenc have a bug that ignore the 'non-standard' setting and still pad the bitrate to 1150Kbits. Make sure you use the latest version.

[mats.hogberg]

None of the tools I have tried so far (except fot Nero Recode) are able to read the VOB files. I'll give ReJig a go, but if it is like the others...

...then there is no problem with the tools, but the VOB maybe? 8)

/Mats