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Playback issues
Hi all.
I recently finished a 6 minute video for a client and authored it on DVD.
I encoded the video at 7 Mbps fixed for continued high quality throughout.
I also encoded pcm 16 bit audio to go along. Very simple set-up with no menus.
Just first play and end play set-up. I tested, burned and watched the DVD on both
home players as well as mac and PC computer DVD players. It played well, looked
great and had no issues. My client tells me that it sometimes hangs up on different DVD players.
Also, that it gets pixelated and the sound drops out. I have tested the same copies and found
no issues whatsoever. I have also checked the bit rate with an onscreen bitrate monitor.
The bit rate never exceeds 6.5 throughout the whole video. BTW, I had 100 copies of this made
from my own master for my client and tested those as well prior to releasing.What gives??? Any ideas… old players? too high a bit rate?? I’m scratching my head.
Thanks in advance Chris
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2 Replies
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If you used a 7mbps fixed (CBR?) bitrate, how come it never exceeds 6.5mbps in your bitrate viewer?
Using LPCM audio, you have your total video+audio bitrate at dangerous (imho) levels (either 8mbps or 8.5mbps depending on if it really was 6.5 or 7mbps encoding).
Were the 100 discs duplicated (burned) or replicated (stamped)?
Also, your total disc usage is well under 1gb — this has caused folks problems in the past, and they fixed it by adding a folder with some “dummy” data to bring the total disc size over 1gb.
Keep your total bitrate at/under ~7mbps — I would try using Dolby Digital audio instead of LPCM.
George
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Don’t forget that the bitrate that the DVD player must process is the sum of the bitrate for the video stream + the total bitrate for all the audio streams + the total bitrate for all the subpicture streams. All of these are interleaved together when the VOBs are multiplexed, and all of these must be played back, even though you can be displaying only one picture stream, one audio stream, and one subpicture stream.
So 7.0 for picture + 1.6 for a PCM audio track = 8.6mb/s.
When you start pushing a sustained 8.0 or above on a DVD-R, that becomes a stress test for the disc and the player.
Bill Stephan
Senior Editor/DVD Author
USA Studios
New York City
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