Setting chapter points in DVD-Lab?!?!?!

[hiptune]

hiptune, you still seem to misunderstand. The I-frame issue is not specific to DVd-Lab. No matter what authoring package you use, chapter points MUST be on an I-Frame.

Hi Bugster,

I completely undertstand the I-frame issue. If you would go try and use TMPGEnc DVDAuthor, you would understand my comments clearly. DVD Lab is more difficult to place chapters where you want them. I love the program, but this statement is fact.

Jeff

[zoranb]

hiptune right now i dont have the ability to check all apps for that matter.

So u clearly mean from what i understand that TMPGEnc DVDAuthor does not have the iframe "problem" and can browse the clip frame by frame, and not iframe by iframe! Right? So that way, it goes from frame to frame, and all is clear. I presume i can set chapters where ever i want them to be!

[hiptune]

hiptune right now i dont have the ability to check all apps for that matter.

So u clearly mean from what i understand that TMPGEnc DVDAuthor does not have the iframe "problem" and can browse the clip frame by frame, and not iframe by iframe! Right? So that way, it goes from frame to frame, and all is clear. I presume i can set chapters where ever i want them to be!

Yes, just about anywhere you want them to be. The fact of the matter is that they don't drift at all like they do in DVDLab.

You'll have to try the free demo. And then you will agree its a better method. I don't have the time to write out everything here. BUt it is so much easier to place chapters in tmpgcnc DVDAuthor.

Jeff

Jeff

[bugster]

hiptune right now i dont have the ability to check all apps for that matter.

So u clearly mean from what i understand that TMPGEnc DVDAuthor does not have the iframe "problem" and can browse the clip frame by frame, and not iframe by iframe! Right? So that way, it goes from frame to frame, and all is clear. I presume i can set chapters where ever i want them to be!

No, I am afraid not. TmpGenc DVD Author, like any authoring app, only lets you set chapter points on I-Frames. It is easier to place your chapter marks visually with TmpGenc DVDA than with DVD-Lab, but you are still limited to I-Frames. This is a requirement of the DVD spec and makes perfect snese when you think about it. (In order to be able to jump to a chapter mark and start playing, the decoder has to be able to display the frame at the chapter point without reference to previous frames, only with an I-Frame is this possible).


The only way to ensure you get frame exact chapter points is to create an mpeg with I-Frames exactly where you want your chapter points to be. I know this can be achieved by encoding each scene seperatley so that each new encode starts with an I-Frame, and then joining them together. If it is possible to specify that specific frames must be encoded as I-Frames within any encoder settings I am not aware of this, though this would be an alternative solution to your problem.

[gwoiler]

One thing that no one is saying here is that you don't have to encode at an "I" frame every 15 franes! I have changed the GOP structure in TMPG and I get an I frame every 12 frames. I have also done it at every 9 frames and tried only 1 B frame consecutively. The TMPG help file here at DVDRHELP that tells how to set up TMPG for High Quality encoding is a real help in this area. TMPG Author lets you "see" which are the I frames so if you offset too much in one direction you can pick the next I frame earlier to get closer to your mark. But again, if you are using sceen detection, and your chapters coincide with different video, you should hit it. I too wish I could hear in DVD-Lab. Also, a good AC3 encoder would be nice.

Is audio delay something that is always a problem when using AC3 audio?

Glenn Woiler

[bugster]

Actually I've just checked an TmpGenc DOES allow you to specify that certain frames MUST be encoded as I-Frames.

On the GOP structure tab is a tick box called "Force Picture type setting". Tick this box and then click the 'setting' button next to it. This opens a dialog that allows you to specify I frames by frame No. You can also preview the selected frames to determine which ones are the scene change and set your I-Frames accordingly.

[zoranb]

still even if u can set iframes where ver u want i think that only one would be made fit, all others will occur to the same pace (evry 15frames)starting from the first one (thats u would set right) so then again u dont have then exactly where u want them! Right?

[bugster]

still even if u can set iframes where ver u want i think that only one would be made fit, all others will occur to the same pace (evry 15frames)starting from the first one (thats u would set right) so then again u dont have then exactly where u want them! Right?

No. This feature will force TmpGenc to encode an I-Frame exactly where you say. After that I-Frame it will continue with the default GOP structure until it hits another frame where you selected fro it to encode an I-Frame. Where you have selected these I-Frames the number of frames from the previous I-Frame can be anything from 1 to 15. So you could have something like:

I 14 I 14 I 4 I 14 I 7 I 14 I 14 I 1 I 15 I ...


if you see what I mean!
(14 as I am trying to show the number of frames between the I Frames).

[gwoiler]

Yes, that is how it is working. Last night I did a test and I have TMPG set to write an I frame every 12 frames. I set it to scene detection, or whatever it is called... (I am at the library) and I opened it up in Author which lets you see where all the I frames are, and sure enough, at each major change of video, there was an I frame. Sometimes the preceeding set of frames was only 2 or 3 frames and then another I frame. So, it works very good. And if that is not good enough, you can set I frames where ever you want, but I think I won't ever need that feature.

I wonder why Author won't burn a -R disc from an image file but will burn it from a volume? Author will burn an image file to a +R though. I wonder if it is the disks? They are BeAll from Memory Media. DVD-LAb won't burn the -R's with an image or from a volume either.

Glenn Woiler

[zoranb]

bugster
can i do that I-FRAME setting so it is 1 frame (rather than 15 or so) from Premiere's 6.5 export to m2v files??

[bugster]

bugster
can i do that I-FRAME setting so it is 1 frame (rather than 15 or so) from Premiere's 6.5 export to m2v files??

I am not familiar with that so I can't help there, sorry.

[zoranb]

what are the disadvantages when creating m2v files with iframe=1frame? the exported m2v files are bigger?

[bugster]

what are the disadvantages when creating m2v files with iframe=1frame? the exported m2v files are bigger?

Well yes, and no

The size of an mpeg file is dependant of the bitrate and playing time. So for a fixed bitrate you get a fixed filesize.

If you encode all I-Frames then each frame I-Frame can contain less data than if you use the more usual IBP GOP structure.

Lets see if I can explain. This is purely example:

With a mythical bitrate of 50 (for each 5 frames)
An I-frame only encode would have frames with say 10, 9, 11, 10, 10 (total = 50)

If you use IBBBP for those same 5 frames you could get something like 20, 8, 8, 8, 6 (total = 50)

So in the 2nd example, the I-Frame gets more data and so becomes higher quality. The intervening frames get less data but only changes between frames are encoded (putting things simply) so less actual data is needed for those.

With a good encoder (and most are these days) a properly encoded mpeg with IBP GOP's will look better than the same movie encoded as I-Frame only at the same bitrate.

Does this make sense, am I explaining it clearly

[gwoiler]

I am not at my NLE computer but I believe you could make your MPEG2 files all I frames. But as far as I know, the I frame has the most information in it and it takes up the most room. That is why P and B frames. I am using 1 B frame instead of the default 2. My file sizes are in the ball park and the video looks great. You are going to have a file size much larger and possibly not have any better looking picture unless your video is very fast moving visuals. Then all the extra I frames would make a difference. The only way I have exported from Premier has been to use the Canopus Soft MPEG to make MPEG2. But, even though it is more or less real time on my system, TMPG makes a lot better loking video at lower bitrates.

Glenn

[Matt D]

I had a problem placing chapters too, but in my case I was able to solve this and place my chapters where I wanted them.
In this case some chapters where 5-6 seconds earlier then where I placed them. To solve this, right click on the chapter mark, select chapters, select set chapter lag. In that pop up it will show the frame index for that chapter. For every second the chapter is early, add 30 to that number. So in my case I added 150 to that number to correct a 5 second error.
It doesn't sound like it should work, but alas in my case it did, and the chapters were placed exactly as I had intended.

[Matt D]

Well I may be wrong, but this doesn't seem to be an I-frame issue. I just authored some TV shows and again the chapters were screwy. On this disc I wanted the chapters during the black out where the commercials were. Now, using the frame advance button in DVD-lab moves forward or backwards one I-frame and using the frame advance clearly shows that there are 6 or 7 I-frames in most of these breaks. This is strange because the chapters were off sometimes by six seconds even though DVD-lab had no problems with me placing them exactly where I wanted them.
I think this must be a problem with the MPG files themselves. Perhaps the way TMPGEnc encodes causes some issue with the timing that screws DVD-lab up? MAYBE it's DVD-lab itself, but so far I have found it to be a very reliable application, so I hesitate to blame it.
Whatever causes it, it's pretty annoying. Burning to RW 2 or 3 times to get the chapters right on each disc just takes way too long.