DVD encoding at low bitrates

john-beale wrote on 3/4/2003, 5:09 PM
My client wants me to put 120 minutes of video on a single DVD-R which means I'm limited to an average video bitrate around 5000kbit/sec. I only just purchased Vegas+DVD, but in my previous experience I have found you need to use temporal filtering to get decent results from MPEG encoders at this bitrate. (Used correctly, these filters remove some random noise, with minimal damage to the real image). As far as I can tell, Vegas 4 does not offer any kind of temporal filtering either in the main editor or the MPEG2 export function. Am I stuck with external stand-alone encoders or external filters to do this task? A program like Virtual Dub works fine, and is even free (www.virtualdub.org), I'm just surprised a $600 program doesn't have this built-in. Thanks for any tips.

Comments

Paul_Holmes wrote on 3/4/2003, 5:30 PM
Do some testing with the Main Concept Encoder and you might be surprised. I've done tests at 4000vbr, 5000vbr, 6000vbr and 8000C. As far as I'm able to tell I can't tell the difference between the 8000C and 5000vbr or higher. At 4000vbr there were definitely moments of the video that were downgraded a bit. The only half-professional thing I've done was a wedding a in September which I encoded at 5000vbr. In the whole hour and 20 minutes my eyes didn't notice anything on the final DVD that made me pause and say I should raise the bitrate.

One caveat. I have a SonyTRV50. Maybe if I had shot with a 3-chip camera the degradation might have been more noticable.
Jamz wrote on 3/4/2003, 5:38 PM
I have put 120 minutes on many DVDs. Main concept does a very good job at this rate.
craftech wrote on 3/4/2003, 5:55 PM
John,

I think the best solution would be to talk the client into splitting it into two DVDs. Tell him that Hollywood DVD's are dual layer which is the equivalent of TWO
regular DVD's and that videographers commonly use two in order to provide quality equal to Hollywood's multi-million dollar replication equipment.

John
john-beale wrote on 3/4/2003, 7:27 PM
Thanks everyone for the advice!

I have done some tests with Vegas' built-in MainConcept MPEG encoder, also the TMPGEnc program, and I do see some differences between 5000k and 8000k MPEGs. My source cameras are good quality (Sony VX2000, Pana DVX100) and I'm looking at the video on a sharp monitor, so I'm probably seeing more than viewers with typical TV sets. But I suppose, if most people are happy with VHS they ought to be at least as happy with a 5000kbps DVD.

I really do want to turn in the best possible quality so I'd like to split the job into two DVD-Rs, but unfortunately I already priced the job assuming one DVD-R (having assumed a shorter length program).

I think there are also differences between DVD players in playback quality (although you might assume that it's all "just digital", it seems to me that some models do better, esp. with interlaced video from camcorders as opposed to Hollywood releases from 24 fps film sources)
JJack wrote on 3/26/2003, 8:30 PM
What was your setting on the video quality slider and what was your audio setting in order to get 120 minutes on a DVD?
jbeale1 wrote on 3/26/2003, 9:24 PM
I did not find the quality of Vegas' built-in MPEG2 encoder to be adequate to my needs in this case, so I can't answer the question directly. I have tried Cinema Craft (CCE Basic) which is OK, but I'm currently using TMPGEnc Plus 2.5 which I find gives me the best results. In order to get 120 minutes I have to set a bitrate around 5000 kbps in TMPGEnc, note that in the TMPGEnc context 1 kbps = 1000 bps, not 1024 bps.
Jason_Abbott wrote on 3/26/2003, 9:45 PM
The latest free PluginPac from Satish has an Adapter that allows the use of VirtualDub filters on the Vegas timeline. If you haven't already heard about it, do a search on this forum for more info.
kkolbo wrote on 3/26/2003, 10:17 PM
I ran tests of the Vegas/MC encoder against hardware encoders that were several thousand dollars. At 5000 CBR the MC was actually better. At 4000 CBR the hardware ones started to look better, but not much.

K
Paul_Holmes wrote on 3/26/2003, 10:25 PM
This is the same as my experience although a lot more subjective. Maybe John knows how to tweak TMPGEnc in a way that gives better results. Ever since I started using Main Concept I haven't tried anything else and all my movies are done at 5000vbr, except for a recent shoot with a VX2000 that I encoded at 6000vbr just to make sure.
jetdv wrote on 3/26/2003, 11:23 PM
The video quality slider should be maxed at 31. Set the maximum bitrate to 8,000,000, the minimum to 2,000,000 and the average to the necessary value to get everything to fit. Then change the DC Coefficient to 10 bits. This should give you satisfactory results.
Paul_Holmes wrote on 3/27/2003, 10:10 AM
I just saved that in my folder of tips, JetDV. I always set the minimum to whatever the extremely low default is, but I'll try your way.
mdotnet wrote on 3/27/2003, 5:30 PM
I do too. Regardless of the max, or avg, I was always under the impression that you want the low at the lowest setting (192,000).

Just out of curiosity, Why do you not allow it to go that low?

Thanks.
craftech wrote on 3/27/2003, 7:27 PM
Do you see a difference when you use a VBR as opposed to a CBR? I haven't tried using a CBR yet. How does the quality compare? Are you able to utilize the space better? Do you get less compression artifacts during fades, pans, and fast motion scenes?

John