need help with video compression .. any help appreciated

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need help with video compression .. any help appreciated

Postby jasonwatkins on Mon Oct 08, 2007 5:51 am

what i'm essentially trying to do is create a compilation DVD of three stand up comedy DVD's - i want to rip each of them and compress them to around 2.7gb each, so they can fit nicely on an 8.5gb DL disc.

What i'm doing at the moment is ripping each one to my hard drive and using avidemux to convert each one to MPEG format, and nudging down the bitrate from the default 9000 to 7000 to reduce the filesize.

Then, I use DeVeDe to reduce the bitrate even further so that i get 3 mpeg files of the right size, then i run qdvdauthor and create my menu system, add all the files and burn away.

The problem I have is that the frame rate of 25fps causes a "wobble" when played back on a PAL television. The reduced bitrate still produces a decent quality file - the actual reduction for each stand up dvd is no more than 20-25%.

As an experiment, I used K9Copy to produce MPEG4 files of each disc, then added them to qdvdauthor, and used the transcode option to increase the framerate to 29.97fps. This actually corrected the "wobble", but produced some other errors - one of the dvd audio tracks was speeded up so the comedian sounded like a smurf :)

If i use avidemux and do a 2 pass run to set a specific file size, that does work but the audio is out of sync on the final file.

So i'm totally stuck - i'm a newbie of only a few months to linux as it is, but i'm a total newbie at this level of video conversion so any help or suggestions, or any idiot guides that you can think of that I can read would be very, very appreciated. thanks.

I've posted this same question on 2 different linux forums so far, and nobody has answered me so i'm hoping it's 3rd time lucky :D
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Postby jasonwatkins on Mon Oct 08, 2007 5:02 pm

i've now posted this question on a total of FIVE forums and nobody has an answer ..

either that, or everyone is ignoring me :D
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Re: need help with video compression .. any help appreciated

Postby dav9000 on Tue Oct 09, 2007 8:00 am

jasonwatkins wrote:As an experiment, I used K9Copy to produce MPEG4 files of each disc, then added them to qdvdauthor, and used the transcode option to increase the framerate to 29.97fps. This actually corrected the "wobble", but produced some other errors - one of the dvd audio tracks was speeded up so the comedian sounded like a smurf :)


In my Windows days I used VirtualDubMod to mess around with .avi, and the changes I wanted to make had to be done to video and audio separately. And I remember that when changing fps I had to do it first to video and then to audio, because otherwise things didn't come up as expected.

I don't know if this helps. Good luck.
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Postby jasonwatkins on Tue Oct 09, 2007 10:28 am

that's interesting to know dav .. thanks ..

i'm still playing around with this - it's just a pain because each time I try and convert the DVD to MPEG, it takes around 3 hours to run through, even though I have a 3.3mhz processor and 1GB Ram :roll:
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Re: need help with video compression .. any help appreciated

Postby scorp123 on Tue Oct 09, 2007 11:42 am

jasonwatkins wrote:what i'm essentially trying to do is create a compilation DVD of three stand up comedy DVD's - i want to rip each of them and compress them to around 2.7gb each, so they can fit nicely on an 8.5gb DL disc.
Hmmm ... I personally find the DVD video format a bit awkward ... you know, all the stuff about the MPEG-2 files having to be in a certain resolution, in a certain format, and all the other trap doors that DVD videos have, conversion to *.VOB and so on .... Really, I always found this most annoying. So when I do something like the things you wrote in your posting, I right away create DIVX or XVID files. DIVX files are way smaller, so more stuff can fit onto a 8.5 GB dual-layer disk, and the funny thing is: Most modern DVD set-top boxes can handle DIVX + XVID and many other modern formats such as MPEG-4. And most people I know (friends, family, coworkers, etc.) have this kind of modern player and when we exchange such stuff (e.g. videos about our family events) we usually do it with these formats ... because they are so much less complicated to get working.

I know ... this is not really the solution you wanted. But sometimes the solution to using complicated formats --and DVD video with all its hassles is such a format-- is *not* to use them and use something else instead. I personally have given up on DVD video creation and all that, for me it's modern formats such as DIVX, XVID, MP4, and so on. Modern players will present you with a file dialogue similar to a filesystem browser on a computer, and you can pick the video files you want to play. From the "user friendliness" point of view this is very much the same like having a DVD menu ... except it's so much easier to get to that result: You just burn your XVID files onto the DVD disk, voila, you're done, the videos can already be watched, no further hassles required.

As I said ... I know this is not the solution you probably wanted to hear. It's just that I have the impression that whoever created the standard for DVD videos didn't really have us home users in mind ... or else I'd assume that the format wouldn't be so damn complicated and put you through so many hassles. (Just my opinion).
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Re: need help with video compression .. any help appreciated

Postby jasonwatkins on Wed Oct 10, 2007 2:50 am

scorp123 wrote:
jasonwatkins wrote:As I said ... I know this is not the solution you probably wanted to hear. It's just that I have the impression that whoever created the standard for DVD videos didn't really have us home users in mind ... or else I'd assume that the format wouldn't be so damn complicated and put you through so many hassles. (Just my opinion).


I do agree with you and i've actually got quite a few discs of just DIVX compilations - I can usually fit an entire TV season on one disc and watch it on my DVD Recorder which does support MPEG4 and DIVX/XVID playback, and i find it incredibly useful.

I only really started doing these compilations as more of an experiment than anything, so there's no real pressing need to get it done because all 3 individual stand up DVD's play without any problems.

it just got to a point where it became a "i'll crack this or die in the attempt" situation :D

I'm in the middle of trying another method at the moment.

I decrypted each DVD to hard drive and I ran each one through DVD Shrink under wine (yeah, i know I could have used K9Copy, but shrink is easier to use just for now).

I reduced the size of each DVD to around 2.8gb and what i'm doing is running avidemux on each reduced DVD and setting a 2-pass conversion to achieve a set file size of around 3gb, in a hope of retaining the 30fps needed for a PAL television.

the theory is that if I can get this size on each stand up disc, then I can produce the DVD in qdvdauthor, and before I burn it out, I run it as a whole through DVD shrink again to squeeze it down to 8.5gb.

if that all works and still reduces the framerate down to 25fps, and produces a "wobble" then I may just have to admit defeat :)
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Postby jasonwatkins on Thu Oct 11, 2007 5:30 pm

i think i can achieve this - but only in windows.

i produced an 8.9gb ISO file containing my full compilation DVD last night and tried to shrink it using DVD Shrink under wine, but it kept crashing due to being "out of memory".

I ran it through K9Copy, but that got to about 40% of the first file and died as well.

I'm just wondering if I should burn the 3 MPEG files to DVD and fire off a windows partition and see if I'm right - i can't really be bothered if i'm honest, but it's still something i want to do.
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Postby jasonwatkins on Sun Oct 14, 2007 6:20 pm

i appear to have solved the problem, but the solution was nothing more than brute force/trial and error.

i kept re-encoding each file and reducing it by 100mb each time until I got to a point where each file maintained a frame rate of 30fps and was also big enough to enable me to fit 3 on the disk.

i'm watching one of them at the moment and while it's not 100% perfect, there is still a small amount of 'wobble', it's 95% good enough for me.
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