NTSC mpeg2 es preset GOP error

[BernH]

Hi, I just wanted to bug report a small error in Edius 8.

I had a project that I wanted to make MPEG2 Elementary Stream files for DVD authoring. When I used the MPEG2 ES preset with default settings, it created strange random decoding problems (severe smearing and what looked like the worst macroblock decode errors I have ever seen) in Encore and on the DVD, (much worse in encore though) I then had a closer look at the default settings for the export preset and noticed the GOP size was at 15, which is the PAL standard, while NTSC should be 18. I changed the setting to 18 and re-exported, and my decode problems were gone.

I never checked through the other NTSC mpeg2 presets, so if you have to use them, take the time to check the settings

[Jerry]

What were the rest of the settings?

[BernH]

First, the source was a 59.94i GVHQ HD render and add to timeline (Shift-Q). The content was mostly talking heads at a podium, so it isn't even like the kind of macroblocking you see from fast motion with too low a bitrate. (ie. betacam-sx shooting a sporting event)

As I mentioned, the glitches on the DVD were much less pronounced than in Encore, but they were still there.

The rest of the settings were:

Segement Encode = off
Size = Current Setting (720x480 picked up from the advanced section in the video format defaults)
Quality = Fine
Bitrate = VBR (used VBR because video was a little over 2 hours long)
Average 4.3Mbps
Maximum 7Mbps
Audio = AC3, 2 Channel, 192K
Upper Field dominant (matching source footage)
Chroma = 4:2:0
Profile = [email protected]
GOP = IBBP
Closed GOP

I have been making DVD's since the mid 90's, when a burner cost around $1000, and have always had the best compatibility with NTSC burned discs using a max bitrate of around 7Mbps, IBBP GOP structure and a GOP length of 18 for 29.97i SD / 59.94 HD source material. Other framerates, from my experience, tend to work better with a GOP of 15 (ie. 25fps, 24fps, 23.98fps)

I know DVD players have come a long way since then, but not every player is created equally, so in my experience, the 20 year old defaults still seem to work best.

[Jerry]

If that's what works for you, the set it manually and move on. I never burn with the program that does my authoring.

[Bluetongue]

I think the problem is trying to get 2 hours onto a DVD!
I have never been able to get a video without artifacting using below 6mb Ave from Edius.
Your specs show 4.3mb average with 7 mb peak, the peak rarely makes much difference when using such a low bit rate, if it uses the peak it has to give it away somewhere else to achieve the average
You need a really good 2 pass encoder to be able to do that, not sure even if Video Master works can achieve that, but worth a try, there is a free trial so may be worth looking at

Best of luck
Barry

[BernH]

I have done that length on DVD many times, but it is getting close to the limit. I agree, a good 2 pass encode is better, but when it is mostly talking heads, a one pass, like the one in Edius is sufficient. Using the bitrates I mentioned gets me about a 92% fill on the disc.

The 7Mb max is strictly set for compatibility when using a burned disc. DVD spec allows for 9.8Mb max, but burned discs have a lower reflectivity, and for some reason, capping the max at around 7Mb seems to help with the players. Once again, this goes way back to the mid 90's when I started making DVD's, and was under advice from Adobe and Matrox, when I used to work at a pro video dealer as a system builder and trainer.

When making from a 23.98 or 24 source, I usually let Encore do a 2 pass encode, and set the M frames to 12, so the stream gets encoded as 23.98, but gets flagged to get the player to do the pulldown.

In the instance where I noticed this problem, I had to get discs out fast, so I set Edius to do the encode since it was very little motion, and the 1 pass encode would be sufficient.

[Ron Evans]

I regularly put approximately 2 hours on a DVD as most stage shows are about this time frame plus or minus 15 mins. I shoot HD, edit HD then export a HQX fine file. Then I use TMPGenc to do a 2 pass VBR encode for DVD preset so that the disc fill is just over 4G ( easily seen on the TMPGenc indicator ). Make elementary streams and author in DVD Architect ( Encore will work too of course ). Burn with Nero most of the time. For the motion on a stage show this works out just fine. Frame rate is 60i timeline even though 3 out of the 4 cameras I use shoot 60P.

Ron Evans

[Andreas_Gumm]

2 hours on DVD5 is not a big issue as long as a proper & efficient MPEG2-encoder is used
to do good 2-pass encoding. Cinemacraft is probably the best you can get, but there are
other encoders at more affordable price tag which can do MPEG2-encoding much better
than EDIUS limited internal 1-pass encoder can do. E.g. ProCoder, TMPEG encoder & a lot
other tools can do even better. Forget the internal Edius encoder if you can't encode at
highest bitrate!

Andreas