DVD bitrates

NickHope wrote on 9/12/2004, 5:57 AM
I've got a 1 hr 55 project that I'd like to fit on a 4.7Gb DVD-R. It's a commercial project of underwater footage to be sold in dive shops. The raw footage is PAL DV. I want 1 or maybe 2 x AC3 soundtracks and maybe some subtitles.

To fit it all on the DVD I reckon I'll need to go with the following settings in either the inbuilt Main Concept encoder or my CCE Basic encoder:

- 2-pass VBR
- minimum bitrate 0
- average bitrate 5 kbps
- maximum bitrate 8 kbps

Do you think that 5k average is going to be enough or should I really be thinking of shortening the project so I can up it to 6k? My test looks pretty good but I'm not so good at making quality judgements with my own eyes.

Thanks

Comments

farss wrote on 9/12/2004, 7:51 AM
I'm hoping you mean 5 MBits/Sec?
Depending on your footage you should be able to get excellent results at that bit rate. I assume as it's underwater the camera cannot move very quickly! I'm not too certain about having the minimum bitrate at 0 though, never tried, could be OK but I leave it at the default, I'm suspecting some players may have a problem if it goes too low and I think the DVD spec is whatever the default is.

Bob.
johnmeyer wrote on 9/12/2004, 9:45 AM
Don't set the minimum to 0. Set it to 1,000,000. That's only 20% of your average, which will leave plenty of room for the encoder to play with.

The footage will likely look OK, but if you are starting with well-lit DV, you will definitely notice problems. Underwater footage may actually be very difficult to encode, similar to smoke and fog which are the most difficult things for MPEG-2 encoding.

However, the proof is how it looks to you. If your tests looked good, and if you picked footage for your tests that is representative of the rest of the project, then go for it.
NickHope wrote on 9/12/2004, 9:59 AM
Thanks guys. Actually my tests so far were minimum 3Mbps, average 5Mbps, max 7bps but I thought I would widen the range for the next tests. I'm glad you didn't come back and say "Oh no, it's got to be 8 mbps average". I think I'll go for it at average 5Mpbs so that I don't have to spend days deciding which 20 minutes of footage to drop from my project!

Underwater is not too much of a problem. I've encoded hundreds of shorter projects at 8Mbps or 6Mbps constant bit rate and they look just like the original DV footage. Perhaps the problems presented by the "fogginess" are counteracted by the slow camera movements.

By the way my Procoder MPEG2 test sucked compared to CCE and Main Concept. CCE was quickest of course, Main Concept seemed to have more contrast, and Procoder was over-saturated (as usual) and artefacty.