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Dull techie question (mpegs)

Posted: 04 May 2004, 22:35
by JansenClone
Dull, dull question...

Is there any way of shrinking an mpeg down from around 225MB to about 100MB? I've got a program that auto compresses them to fit onto a VideoCD but it seems to go too far and shrink them to about 30MB...

I know, I know...

JansenClone

Posted: 04 May 2004, 22:39
by Quiff Boy
can you adjust the frame rate? or maybe lower the audio bitrate?

i;ve done some work recently on a few ghost dance videos (oops! should i have said that? ;) :innocent: ) and i used a piece of software recommended by dan called "TMPGEnc" - http://www.tmpgenc.net/ 8)

Re: Dull techie question (mpegs)

Posted: 04 May 2004, 23:27
by Dan
JansenClone wrote:Dull, dull question...

Is there any way of shrinking an mpeg down from around 225MB to about 100MB? I've got a program that auto compresses them to fit onto a VideoCD but it seems to go too far and shrink them to about 30MB...

I know, I know...

JansenClone
First, don't even think about changing the framerate or the audio bitrate. That's not the way.

Is it mpg1 or mpg2?

Standard mpg1 is 10mb per minute and you don't wanna go any lower than that. Standard mpg2 used to be 20mb per minute but lately people seem to be encoding them larger and larger.

If it's mpg2 then some of them can be stupidly large. If you're re-encoding mpg2 to some other format you'll wanna de-interlace it cos for some reason a lot of (or all?) mpg2's are interlaced. I have no clue why, cos it looks cr@p. (You can spot interlaced video cos when theres any fast motion the horizontal lines go all cr@ppy.)

Posted: 05 May 2004, 18:40
by JansenClone
Cheers guys, I'm playing around to see what can be done. There the files I got when I ripped a couple of tracks from a bootleg dvd to make a VideoCD. Weeding type thing coming soon as they say.

BTW QB The Chameleons are on BBC6 Dream Ticket next Wednesday, though I suspect it's a repeat. Also got an mpeg clip of 'In Shreds' with them looking ever so young...

Any advice please ?

Posted: 29 Nov 2004, 22:09
by Ocean Moves
wouldn´t want to start another DULL thread, hence my question as follows:

I´ve captured from a miniDV camcorder via firewire to one large
AVI file. I´ve encoded it to DVD using TMPENC XPress3, and authored
it to DVD using TMPENc Author 1.6.

plays fine on the TV, although when played in nero showtime on my
pc (laptop) it showed very harsh fine horizontal jagged line breaks,
characteristic of interlacing.
I understand that this is because a PC TFT screen is not interlaced, like a
TV (where the problem doesnt occur).

I now have power DVD 4.0, and winDVD 5.0.11 installed, since I was told
that they "deinterlace on the fly" hence I should not expect to see
the jaggedness described above when playing back on PC, any longer.

However, all I seem to have got is a reduction in the lines; on square
objects that are moving, I still see a alittle of the jaggedness described
above, even playing in WinDVD.

is this normal ? does software de-interlacing only
partly work? or am I doing something else wrong ?

does my encoder (TMPENC XPress3) deinterlace my AVI file and then re-interlace it? if so,
why?

and why do commerical DVDs look PERFECT on a PC TFT screen AND
a TV ? is it interlaced? or something else?

yours, bloody confused by interlacing,
E

re

Posted: 29 Nov 2004, 22:49
by Ocean Moves
this appears to answer most of my question...
http://www.dvd-player-software-review.t ... acing.html
Although all DVD player software comes with de-interlacing ability, not all DVD player software is created equal. Each one uses different combinations of de-interlace tools to produce the proper picture, some methods superior to others. The closer the DVD player software comes to backtracking to the way the video was interlaced in the first place, the better the final video version will be.

So, when you are evaluating the video quality of your DVD player software, the essence of what you are judging is the worth of the program's de-interlace algorithms. Everything else is frosting.
Anyone have an opinion on the validity of this paragraph?

Re: Dull techie question (mpegs)

Posted: 30 Nov 2004, 00:00
by VonOben
JansenClone wrote:Dull, dull question...

Is there any way of shrinking an mpeg down from around 225MB to about 100MB? I've got a program that auto compresses them to fit onto a VideoCD but it seems to go too far and shrink them to about 30MB...

I know, I know...

JansenClone
I'd recommend the Xvid-codec (mpeg4) and the program VirtualDub. However, most DVDs won't be able to play the resulting avi-file. Anyhow, it's a great codec.

Posted: 30 Nov 2004, 00:11
by CellThree
So following on from this, what is the best way to convert a DivX / Xvid file to MPGEG2 so I can burn it onto CD? TMPGenc will convert a 40 min 350mb Xvid file into something around 4gb. This is way too much for one 40 min file isn't it?

I have DVD player capable of playing these files, but I need to burn playable DVDs so they can be played on any DVD player.

Posted: 30 Nov 2004, 00:24
by Dan
If you're converting interlaced video to another format with virtualdub or tmpgenc you need to select the deinterlace option otherwise the new video will still be interlaced.
CellThree wrote:So following on from this, what is the best way to convert a DivX / Xvid file to MPGEG2 so I can burn it onto CD? TMPGenc will convert a 40 min 350mb Xvid file into something around 4gb. This is way too much for one 40 min file isn't it?

I have DVD player capable of playing these files, but I need to burn playable DVDs so they can be played on any DVD player.
A 40 min file in a DVD format will be gigabytes in size. I don't know much about encoding dvd files but if you're able to change the video bitrate or screen resolution then try lowering it.

A 350mb xvid file is too small to be anywhere near dvd quality so you could convert it to SVCD instead where a 40 min video would be around 800mb. Encode to around 2500kbps and it should fit nicely on one cd burnt as SVCD.