Pulldown increasing bitrate?

[doctorm]

I've been working with a German version of a movie and editing in the audio track from an english language version using Womble Mpg Wizard.
Things have been smooth and I burned a test disc.
After watching the film I found a couple things to tweak (a bad frame and some audio edits needed to be smoother).
Anyway, I edited using the saved project, resaved the video and audio, did the usual pulldown on the video from 23.976 to 29.97fps using DGPulldown and then things went bad.

My authoring software warned me that the bitrate got too high. I checked with BitRate View and confirmed multiple spikes in the bitrate well over 9000kbps. The problem is: the raw video file BEFORE applying the pulldown is within the specs I encoded and doesn't exceed 8200kbps.

I've now attempted various re-saves from womble, re-pulldowns and I have the same problem.

Now I thought DGPulldown only changes flags, how can this effect the bitrate? Should I ignore the errors or what? I mean what is going on, this is the first I've ever seen anything like it. Why didn't this happen last time when I generated the test disc?

[manono]

Hi-

I thought DGPulldown only changes flags

That's true of DGPulldown and of Pulldown.exe. No reencoding is being done, so how can the bitrate change?

...how can this effect the bitrate?

Obviously it can't.

I checked with BitRate View and confirmed multiple spikes in the bitrate well over 9000kbps.

Bitrate Viewer is wrong for NTSC. If the max was 8200 before running Pulldown, it was 8200 after Pulldown. Whan I check bitrate in Bitrate Viewer, M2Vs that I know are OK, it routinely gives me max figures of over 11000. In that box with text, you can scroll up and see what max bitrate was set.

If your Authoring app is only warning you, then ignore the warning and go ahead and author. If it doesn't let you, then get a different app.

[doctorm]

Really? I would have thought that the authoring software (in this case DVDMaestro) would know a buffer underrun when it sees it.

Did a quick rw test burn and skipped to the worst spike times on the disc and it played fine.

I feel dirty ignoring an authoring warning...

[manono]

Hehe, I know the feeling. You always figure these apps know more than you do, and you ignore their warnings at your own peril. I'm a simple man and know nothing about Maestro. Maybe someone else around here has seen that warning and can elaborate on it. I use Muxman, IFOEdit and DVDAuthorGUI. As far as I know, the authoring apps can't spot buffer underruns until they are actually doing the muxing. I could be wrong about that, though.

I always try and max out the max bitrate, and sometimes do get buffer underruns. If there are just a few of them, the mux usually completes, but in those cases I have seen brief instances of jerkiness during complex scenes when playing the DVDR. Of course, if there are too many buffer underruns, they abort before finishing. If there are no buffer underruns reported either on the computer screen or in the log, I've never had a problem.

[jman98]

DVD Maestro is NOT a professional DVD burning tool. It enforces things that are contrary to DVD specs. I have an old laserdisc of a foreign film that had never been released on DVD anywhere, so a couple of years ago, I recorded it to my PC and tried to use Maestro to make a DVD out of it. I had one GOP that for some bizarre reason had 16 frames in it instead of 15. I tried re-editing, re-recording the side and I kept having this problem. Maestro vomited every time on my video clip. NTSC DVD actually allows for up to 18 frames in a GOP for DVD, so Maestro was wrong in rejecting my clip. I learned to author in Scenarist and Scenarist accepted the clip with no problems. I believe that Maestro also won't allow you to use MPEG-1 video in DVD. Technically, this is legal if you use certain bit rates and resolutions and it's not real useful in my opinion, but I believe Maestro forbids it. It's just another example of Maestro being anal about something it shouldn't worry about it.

[SLK001]

Bitrate Viewer has a widely known bug in calculating the bitrates for videos with a pulldown flag applied. They plan on fixing the bug in the next release (if they ever release another version).

[doctorm]

Actually I've made a compilation of VCD using Maestro and it took the mpg1 files just fine.