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URGENT!!! DVD ENCODING PROBLEM

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Lauren
URGENT!!! DVD ENCODING PROBLEM
on Oct 12, 2005 at 1:51:02 pm

Hi-

I am having some serious problems with DVD encoding - the work is for a large exhibition which opens on Friday so I need to get this worked out immediately.

The work is a three channel installation and the problem seems to be happening on all three of the DVDs I made (and on two different models of players). Each DVD is one hour long and there is only one chapter marker at the end (in order to work with the sync device).

Apparently (as I am being told - I am in NYC and the work is being installed in Philly) the DVDs play fine for 15 minutes and then start to break up. One the professional Pioneer players they stop playing altogether and on other players they continue to play but the image breaks apart.

I encoded the DVDs out of FCP 5 with a 2 pass VBR and a quality of between 7-8. I burned the discs out of DVD studio pro 4 onto Apple DVD-Rs. My computer is a dual 2ghz G5 - 10.3.9.

If anyone has any suggestions please send them off AS SOON AS POSSIBLE!!! There is a large opening planned for Friday night so everyone is in a panic.

Thanks,

Lauren


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Alex Alexzander
Re: URGENT!!! DVD ENCODING PROBLEM
on Oct 12, 2005 at 2:33:54 pm

If your MPEG-2 encode is peaking at 8 Mbps, and you are using AIFF for the audio, then your peaks are at a whopping 9.5 Mbps. That is a very high number for a DVD-R media and your DVD player to handle properly.

I quick fix is to first convert that AIFF audio from its native 1.5 Mbps to lower bitrate of 192k stereo AC3 and see if the problem goes away. You'll be peaking at around 8,192k at that point. If after that your DVD still stutters and breaks apart, then you may need to re-encode the MPEG-2 asset at a lower bit rate, such as 6.5 Mbps.

Here are few things you do to check what's going on.

If you have a PC around the place, and have a program called, PowerDVD, you can set an option in PowerDVD to show the effective bitrate. I do this a lot to test a DVDs bitrate shifts while playing.

Consider how fast the media was written to. Some people think it is a good idea to record DVD-Rs at 16x or 8x. This can easily cause problems. I have seen many 16x DVD-Rs just fumble all over the place, while 2x and 4x DVD-Rs with the exact same encoded materials play perfectly. Now, it's not always a good idea to use very high speed media at lower bit rates. If possible, buy 2x media and record at 2x, or buy 4x media and record at 4x. Varying speed ratings on the media itself mean a different chemical coating process is being used, and some appear to be better than others in terms of overall quality and stability.

Also, watch the same area that are the problem on the hardware DVD player on the computers software DVD player using the VIDEO_TS folder from the build on the hard drive. If there is no problem there, than at least the problem is likely the media you used, the record speed you used, or the bit rate you used. If the problem shows up even while playing the DVD through the software player directly from the VIDEO_TS folder on the hard drive, then the problem is much deeper than just media, or record speeds of media.

Try the easy things first, as they may solve the problem without a re-encode. If all else fails, try to re-encode at 6.5 Mbps with Dolby Digital (AC3) 2 channel stereo at 192 - 224k.


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Lauren
Re: URGENT!!! DVD ENCODING PROBLEM
on Oct 12, 2005 at 3:10:53 pm

Hi-

Thanks for all the information. I neglected to mention that two of the videos are silent and one only has 30sec. of audio right at the end - so I am afraid that the audio is probably not the problem.

The discs were 8x discs burned on 8x writers. But perhaps we can try at a slower speed.

My general feeling is that the bit rate is just too high. I use 7-8 all the time but on much shorter projects so perhaps the length of this project is coming into play.

Also, is it still a problem not to have any markers in a really long file? I remember in studio pro 2 having to place markers about every 15 mins in a long file. I just made another hour 1/2 dvd for duplication on my same system and everything was fine. The only difference is that is was a compilation of short films so there were markers about every five minutes.

Lauren


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Jason Casey
Re: URGENT!!! DVD ENCODING PROBLEM
on Oct 12, 2005 at 8:01:44 pm

Doesn't really matter if there is no audio in the audio track. It still takes up the same amount of space and adds to the bitrate even if there is no audio within the audio file. I agree with the others...your bitrates are too high. Either use AC3 audio (even if there is nothing there) or lower the video bitrate.


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Dave Friend
Re: URGENT!!! DVD ENCODING PROBLEM
on Oct 13, 2005 at 12:37:58 pm

Lauren,

As your video is only about 60 minutes in length you can use a CBR encode which may help playback reliability a bit. Try 6.5 or 7.0 Mb/s and, even though there is hardly any audio, encode it as ac3 at 192kb. Make the burn a 1x and use good quality discs.

Unless there is some studio pro issue I'm not aware of (I'm not a SP user) the number of markers should not affect playback reliability.

Dave


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David Roth Weiss
Re: URGENT!!! DVD ENCODING PROBLEM
on Oct 14, 2005 at 5:40:41 pm

To add to what Dave said, there have been problems reported with Compressor's VBR compression, so there's another good reason to encode using CBR.


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