'Convert to Disc Template' greyed out, .mpeg, .ac3 help

torana_79 · Post by **torana_79** » Thu Jul 19, 2007 12:20 am

Hello,

Im in a real bind here, i some quicktime files created on a mac using Final Cut Pro (24bits, 720x576, 25fps). The files are imported fine and i can burn the finished project to dvd but when it comes to playing the video there are ever so slight jerks consistently thoughout it.

From reading the forum i though unchecking the 'Convert to Disc Template' option in the Edit option of DWS2 would prevent re-encoding and perhaps solve this problem but... its greyed out?

Thanks
Dan

sjj1805 · Post by **sjj1805** » Thu Jul 19, 2007 1:14 am

When it is greyed out it means that your files are NOT compliant and so MUST be converted.

torana_79 · Post by **torana_79** » Thu Jul 19, 2007 1:16 am

Thankyou sj1805, why is it we always read the help files after all else fails...

Will be converting to mpg-2

DVDDoug · Post by **DVDDoug** » Thu Jul 19, 2007 1:20 am

That's not the problem...

Workshop will convert your files without giving you a choice, because your Quicktime files are not DVD compliant.

Try saving your file (from Final Cut) in MPEG-2 instead of Quicktime. I assume that Final Cut gives you a choice called "MPEG-2 DVD", or something like that. (Not all MPEG-2 is DVD compatible.)

720x576, 25fps is good for a PAL DVD. You also need DVD compatible bitrates and GOP size... and maybe some stuff I don't know about...

torana_79 · Post by **torana_79** » Thu Jul 19, 2007 1:26 am

Hello DVDDoug,

I am getting some of the quicktime files output as MPEG-2 instead of quicktime, i will double check that the MPEG-2 is dvd compatible.

Im not sure what GOP is but i have been told a calculation on how to work out the best bitrate for the video in the dvd.

560/Total Time - 1.5 = video bitrate

I guess i am a bit of a newby at this.

Thanks for the heads up.

sjj1805 · Post by **sjj1805** » Thu Jul 19, 2007 1:38 am

GOP = Group of Pictures. It is a MPEG format thing - part of the compression algorithm

Here is an explanation:
Wikipedia

Or in "English"
The I frame is a complete picture. The next few frames ( P and B frames) contain changes to that picture until you reach the next I frame - normally about 15 frames apart. Its a way to try and reduce the overall file size.

torana_79 · Post by **torana_79** » Thu Jul 19, 2007 1:45 am

Thankyou sjj1805, that makes sense. So the more frequent the I frame the larger the frame but better quality to some extent.

If the output video is jerking at regular intervals when panning, then possibly the I frames is too far apart?

What would be a good start? 15 frames between I frames or is it more of a trial and error thing?

Thanks
Dan

sjj1805 · Post by **sjj1805** » Thu Jul 19, 2007 1:54 am

There is a comprehensive article here by Terry Stetler
MSP/VS/MF: Encode MPEG's from clips with fast motion

torana_79 · Post by **torana_79** » Thu Jul 19, 2007 2:07 am

Sjj1805, thankyou for all your help. You have saved me alot of time and grief. Hopefully this will fix the problem.

Cheers
Dan

DVDDoug · Post by **DVDDoug** » Thu Jul 19, 2007 6:48 pm

The only resaon I mentioned GOP was to point-out that sometimes you think you have an MPEG that is DVD compatible, but Workshop still wants to re-code it...

So the more frequent the I frame the larger the frame but better quality to some extent.

At first you might think so, but.... no. Since the bitrate limits how much overall data is being used for the video, and I-frames eat-up more data, there is less data available for the other frames. By choosing a smaller GOP size you are forcing the MPEG encoder to make "different" compromises. It might look better or worse, depending on the source material.

If the output video is jerking at regular intervals when panning, then possibly the I frames is too far apart?

I don't know what would cause that, but I doubt it's the GOP setting.

What would be a good start? 15 frames between I frames or is it more of a trial and error thing?

That should be OK. (Most of my MPEGs are 15*) I don't remember exactly, but I think the DVD spec requires the GOP to be less than 18. I'm not sure if there's a minimum. And, it might be different for NTSC an PAL.

* That works-out to one new I-Frame every 1/2 second, for NTSC video, which is 29.97 frames-per-second.

torana_79 · Post by **torana_79** » Fri Jul 20, 2007 1:51 am

Thanks DVDDoug, i got the files exported as .m2v burnt a test without ulead compression and worked a treat. But...

im probably getting way of topic now but the dolby sound file (.ac3) will not import to ulead, its giving me an invalid format error... I installed a few filters and can see it in my add remove programs (ac-3 acm codec, AC3Filter). The files were created on a mac using final cut pro. I also have an .aiff file but do not have the option to import it with ulead. Final cut pro doesnt seem to output wav files.

I am going to have to convert all the .ac3 files to .wav unless i can work out a fix for this.

Thanks again for all your ongoing support, i will edit the original post subject heading so its relevant.

Devil · Post by **Devil** » Fri Jul 20, 2007 7:56 am

If you have a dvd compliant mpg file with valid ac3 audio, WS2 will NOT re-encode it, unless you force it to.

GeorgeW · Post by **GeorgeW** » Fri Jul 20, 2007 10:56 am

Does your version of DVDWS2 have an AC3 encoding option

Regards,
George