Hi
Most common origin to this are:
Brand of DVD used - NoName, Memorex etc cheap brands might work as Data-DVDs - BUT NOT as Video-DVDs
Type of DVD used - I only use SL-DVD-R as they also playback on older DVD-players. DVD+R for newer DVD-players. Never ever DVD+/-RW. Dual-Layers usually creates more problems than Single-Layers
BURN SPEED - Very IMPORTANT factor - I never go faster than x4 - Normally I use x2
Material used - Video Codec, Photo and Audio file formats
Video-Codec: StreamingDV, AIC and HDV (I use)
Photo: .jpg - NO .bmp or other - all converted to .jpg first
Audio: .aiff 16-bit 48kHz or 44.1kHz (as on Audio-CDs) - NO .mp3, wma etc ailient formats - all converted to ..aiff 16-bit 48kHz or 44.1kHz first
Free Space: on Start-Up (Macintosh HD) Hard Disk - I never go less than 25Gb when doing Video-DVDs (for SD-Quality Video - if HD material is used 4-5 times more are a safe low level) (Other external Hard Disks - DO NOT COUNT as space here can not be addressed by Mac OS or iDVD for it’s massive use of .temp files)
Dusty DVD-burner Laser: I use a Cleaning DVD (no liquid but the one with brushes) from time to time.
Harmed DVD-burner Laser: Easy to do by burning more than three DVDs at a time - I let it rest for 30 minutes till next batch of three DVDs. If this happened - then only a costly repair will help. It will not heal by it self.
OBS: There are more than one Laser in the DVD-Burner so other functions might work OK as Playback CD/DVDs and even burn CDs. Still being broken.
Yours Bengt W