Damon_C
Member
The first thing to keep in mind is that you will not be able to get 'Hollywood quality' DVDs and still put 90 minutes or 2 hours on a single disc. The disc labels that say '2 hour capacity' should be totally ignored, the same way you ignore VHS labels that claim you can fit 6 hours on them.
Hollywood DVDs are not 'burned' in the traditional sense, they are basically screenprinted, and two layers of data are sandwiched together. They're called DVD9's, and most of them are 9.5 gb. Big studios also use hardware encoding boards, which encode mpegs in real-time as they capture your video from the deck. The best ones cost around $15k, and produce stunning image quality.
Burning discs at home is a lot more limited. You have a single layer disc, and software mpeg encoders. You want to try and maintain the highest possible image quality within these limitations. Bitrate is king when it comes to image quality- the higher the bitrate the better.
At the highest bitrate that the DVD spec will allow (8 mbps for the video portion, approx 1.7 mbps for the audio), you will only fit about 60 minutes onto one disc. If you use Dolby AC3 audio instead of PCM, you'll add about 10-12 minutes to that. This is the baseline you should go by- anything more than 70 minutes of video on one disc, and you will be forced to sacrifice image quality. If not using Dolby, 60 minutes is your limit.
You can minimize the sacrifice by using variable bitrate, multipass settings in a good encoder. This means the software scans the video and uses a lower bitrate in the parts that don't have much action. It saves room, but still sacrifices quality. It also takes a lot of processing time.
To get the highest possible quality (with software) you would use a <60 minute mpeg2 encoded at 8 mbps constant bitrate.
The bitrate setting is found in almost all editing programs, in the export window. Set it up to export as mpeg2, with the bitrate on CBR (constant bitrate), or VBR (variable). As a general guide, here's what you can fit on a DVD-R, assuming you are not using Dolby audio:
8 mbps = 60 min.
6 mbps = 1 hr. 15 min.
4 mbps = 2 hrs., but at half the quality of a commercial disc
2 mbps = 4 hours - at this setting, it's looking like that 14th generation Night Flight video dub you got from your friends brother who had a cool Camaro in '86.
If image quality is a serious concern, don't exceed 65-75 minutes on a DVD-R.
Here are some of the other settings required to meet the DVD spec:
audio- 48khz PCM or Dolby
GOP size- 15 frames
Field ordering- Lower Field First
Resolution- 720x480
Dual-layer burners are becoming cheaper and more common, which alleviates most disc capacity concerns. Also, next-generation DVDs are not too far off, such as Blu-Ray, and these discs will hold a mind-boggling amount of data- 35 gb or so. With these, the whole DVD spec will change and it will probably introduce HD-DVDs as the new dominant format. Couple that with an HD widescreen TV, and it will be hard to leave the house.
Hollywood DVDs are not 'burned' in the traditional sense, they are basically screenprinted, and two layers of data are sandwiched together. They're called DVD9's, and most of them are 9.5 gb. Big studios also use hardware encoding boards, which encode mpegs in real-time as they capture your video from the deck. The best ones cost around $15k, and produce stunning image quality.
Burning discs at home is a lot more limited. You have a single layer disc, and software mpeg encoders. You want to try and maintain the highest possible image quality within these limitations. Bitrate is king when it comes to image quality- the higher the bitrate the better.
At the highest bitrate that the DVD spec will allow (8 mbps for the video portion, approx 1.7 mbps for the audio), you will only fit about 60 minutes onto one disc. If you use Dolby AC3 audio instead of PCM, you'll add about 10-12 minutes to that. This is the baseline you should go by- anything more than 70 minutes of video on one disc, and you will be forced to sacrifice image quality. If not using Dolby, 60 minutes is your limit.
You can minimize the sacrifice by using variable bitrate, multipass settings in a good encoder. This means the software scans the video and uses a lower bitrate in the parts that don't have much action. It saves room, but still sacrifices quality. It also takes a lot of processing time.
To get the highest possible quality (with software) you would use a <60 minute mpeg2 encoded at 8 mbps constant bitrate.
The bitrate setting is found in almost all editing programs, in the export window. Set it up to export as mpeg2, with the bitrate on CBR (constant bitrate), or VBR (variable). As a general guide, here's what you can fit on a DVD-R, assuming you are not using Dolby audio:
8 mbps = 60 min.
6 mbps = 1 hr. 15 min.
4 mbps = 2 hrs., but at half the quality of a commercial disc
2 mbps = 4 hours - at this setting, it's looking like that 14th generation Night Flight video dub you got from your friends brother who had a cool Camaro in '86.
If image quality is a serious concern, don't exceed 65-75 minutes on a DVD-R.
Here are some of the other settings required to meet the DVD spec:
audio- 48khz PCM or Dolby
GOP size- 15 frames
Field ordering- Lower Field First
Resolution- 720x480
Dual-layer burners are becoming cheaper and more common, which alleviates most disc capacity concerns. Also, next-generation DVDs are not too far off, such as Blu-Ray, and these discs will hold a mind-boggling amount of data- 35 gb or so. With these, the whole DVD spec will change and it will probably introduce HD-DVDs as the new dominant format. Couple that with an HD widescreen TV, and it will be hard to leave the house.
