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Not another compatibility question?!

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Dylan Tucker
Not another compatibility question?!
on Apr 5, 2007 at 4:22:25 pm


Hello all. I know we are all getting sick to death about questions regarding DVD compatibility, but I think this may be useful to clear up with everyone. I recently have finished quite a large DVD project, however have faced a certain compatibility issue with my client's players. The discs I was using were DVD+R Dual Layer Fortis Discs, which I heard were good, but I didn't realise they were also RW (sneakily hidden logo) so I guess that could have definately been one hinderence. I am now using Verbatim DVD-R DL. I have also read that Nero can have a problem with break-points on dual layer dvd's, so I will try another program. However, I want to make sure that this time, I can get the disc as compatible as I can. I have done a lot of reading on the net and in terms of a safe maximum bitrate, some say 6 and some say 7 or 7.5. What is the best?! I'm talking total bitrate as well (All my audio is done at AC3 192kbps). Most of the video on the DVD has 2 angles, and I have also heard that multiple angles doesn't work the same as multiple audio streams; that is, they don't add up. My problem is, for example, even if I am running at a max of 7mbps, with the audio, that leaves me only 3.9mbps per video track if they do both get included in the max bitrate, which means it's too small even for VBR, as the smallest maximum bitrate is over this amount. I know that a max bitrate of 6 probably is the safest, but obviously with my two video angles, I need all the quality I can get. A los of the rest of the DVD is animated however, and I can get away with 6 for that. Any help with these issues would be greatly appreciated.

Regards,

Dylan Tucker



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lukeny
Re: Not another compatibility question?!
on Apr 5, 2007 at 5:14:54 pm

"I am now using Verbatim DVD-R DL"
Dual layered disc are not very compatible with some DVD Players. If this is going for replication I would stay away from providing the replicator with DL media. I would use DDP on two DVD-Rs, DDP on Hard Drive, or DLT.

"I have also read that Nero can have a problem with break-points on dual layer dvd's, so I will try another program"
You are correct. However the problem with burning a DL DVD with Nero/Toast/etc. is you have the possibility of creating a seamless layer break which is not supported in the DVD spec. The reason for this is you create a layer break in the authoring system, but when you go to burn the DVD, Nero will fill Layer 0 up to the end and then continue on Layer 1. This means if Nero creates the layer break itself it may end up on a Seamless cell and not where you originally intended.

"My problem is, for example, even if I am running at a max of 7mbps, with the audio, that leaves me only 3.9mbps per video track if they do both get included in the max bitrate"
The max is 7.8 mbps per angle. I would stay around 5 or 6 as a max when doing multiple angles. Also keep in mind the video MUST be the same length and same GOP structure. Which means encode all video on the same encoder card/software with the same settings for all angles.


Hope this helps

Lucas F
Premastering Engineer


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Dylan Tucker
Re: Not another compatibility question?!
on Apr 5, 2007 at 6:22:08 pm

Thankyou for your reply, Lucas. In regards to the issue with Nero etc, I am creating the project on my powerbook in DVDSP, with only a single layer burner, so what do you suggest for burning? I will probably go with DDP on two DVD-R's for the replication facility, but what about for supplying proof copies to clients?

Also, with the multiple angles you mentioned, does this 5/6mbps guideline include the audio? If I was to use VBR, what average and maximum would you suggest? (With AC3 audio of course.)

Thanks a bunch.


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George W.
Re: Not another compatibility question?!
on Apr 6, 2007 at 2:05:56 am

The bitrates for the video angles are not combined against the max bitrate, but there are some limitations depending on number of angles (and this might vary depending on your Authoring software). For DVD SP:
<= 5 Angles = 8mbps Maximum for the track's combined bitrate
6-8 Angles = 7.5mbps Maximum for the track's combined bitrate
9 Angles = 7mbps Maximum for the track's combined bitrate

NOTE: when calculating the combined bitrate for a track, you only need to add in the bit rate of one video stream, but it needs to be the stream with the highest bit rate.

Regards,
George


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dylan Tucker
Re: Not another compatibility question?!
on Apr 6, 2007 at 2:25:12 pm

Thanks George. I have also been advised to keep bitrate overall on the dvd from exceeding 6mbps. Especially if I'm having compatibility issues I thought I might do this?

My main query at the moment is this: If I am creating a dual layer dvd and am getting it replicated at a dvd plant, what is best to give to the client as a version for viewing? I understand that DVD-R DL's don't work in all DVD players and that I will always face issues until I get it replicated, but what do other people do?

Also, is it really true that I should supply the plant with the project on DLT? I was going to supply it on two blank discs, but then there is the issue of a break point, and will it really be risky in terms of errors?

At the moment, clients players are doing strange things, like not only players freezing up, but default buttons being different etc. Why is this?

Thanks a lot for the help, your or anyone else's reply would be greatly appreciated.



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George W.
Re: Not another compatibility question?!
on Apr 6, 2007 at 3:02:56 pm

For DL discs, I would recommend DVD+R DL (Verbatim), and setting the booktype to DVD-ROM (if supported by your burner). I use IMGBURN to set the booktype and burn DL discs (NOTE: I am PC only, no MAC experience).

6mbps is a nice conservative number. How long is your DVD, and how many angles (are they mixed or multi or both)? Also, how many audio tracks, and what format audio are you using?

Sorry, I haven't replicated DL projects, so hopefully others with that experience will provide their input.

Regards,
George








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lukeny
Re: Not another compatibility question?!
on Apr 6, 2007 at 7:52:55 pm

I am a Premastering Engineer at a replicator and I would highly recommend DLT and stay away from dual layered media for replication. DL will be supported very soon but for now stick with DLT or DDP on dvd-r's or hard drive. Plus DDP you can submit a master with copy protection. The BEST way to get your project to your client is to have the replicator provide a check disc. This is expensive but it will be the most compatible with DVD players as it IS what the final product will be. If you do go this route make sure you check every little detail before ordering a check disc, like I said this is costly.

So long as you setup the layer break correctly and have either two DLT's created from the authoring system or a layer0 and layer1 folder burned to two dvd-r's don't worry about the layer break it will be fine. Plus we place any job on hold for seamless layer breaks and other replicators should as well.

Luke


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dylan Tucker
Re: Not another compatibility question?!
on Apr 6, 2007 at 8:56:48 pm

Thanks George and Luke, I will try and reply to what you are both saying here.

Luke, I have already purchased DVD-R DL (Verbatim). I heard that minus was more compatible. Is this not true. Either way, is there much difference, would this still be fine? I think I have only one plus disc floating around. I have not heard of booktyping I'm sorry, the drive I am using is a LG 'super multi' drive of some sort. The DVD is not a long running film, but instead has lots of different short clips, with a total footage time of around (very rough) 140 mins. Only one story uses two angles, the rest is only one. I have also another story separate to this that uses four audio streams, but the rest only has one. Audio format is AC3 192mbps. I am playing it safe with a combined total of 6, (so around 5.8mbps for the video) and using cbr for half the footage as it is animated, and I find VBR either looks worse or does no justice to animated footage. I'm a little uncertan though, If I am restricting my video footage to 5.8, where I should have my average and maximum bitrates for VBR encoding. Should the max be at 6 or the average? I am aware that 6 gives me a bit of headroom. And yes, as DL is still growing, perhaps we can all help from this.

George, thanks for your professional advice. I currently do not own a DLT drive, do you many errors occur from submissions via the two disc method with DDP? The thing is, I can understand why DVD's might freeze or glitch etc if players are not compatible, but clients are reporting that different buttons are going to different places, default buttons are changing etc. Have you heard of this before? I thought I must have made a mistake, but went back to the project and my disc, and everything was fine! The check disc does sound a good idea, but I am not sure if the producer will be willing.

I am almost overwhelmed with the help, many thanks.



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Brett Clark
Re: Not another compatibility question?!
on May 9, 2007 at 5:48:39 pm

Hi there...had to crash in, but "-R's" are more compatible as far as I know on the 4.7 discs, but as far as dual layer goes...dual layer is not dependable until the more recent players are released that are compatible to dual layer discs. If I am wrong, someone can chime in because it still a bit sketchy to me. I've had hit or miss with dual layer discs.

Rice Crispies!

BClark


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