CCE Video/GOP settings

[nad]

I am wondering about some of the options in the Video settings of CCE before doing the first pass. Especially the progressive frames, field top first, zig zag.

My question: Is there anything I need to know about bitrateviewer like bugs or problems???? I feel that it is sometimes showing the improper settings when it analyzes the VOBs, and then I set improper settings. What should I be sure of? I know my movie has progressive frames.. Does this mean I should always set "Progressive frames" in CCE even though bitrate view might show Interlaced for some reason? I mean sometimes it even shows Progressive frames in bitrateviewer and then the DCT Type says Field?? or it will show Interlaced when only 1-2 frames at the very start of the movie are Interlaced, and the rest of the movie is Progressive.. but it will show the DCT Type as Frame?

Next, about GOP settings.

My question: Can I get any recommendations for setting a more accurate GOP structure during the GOP configurations in CCE??? Like if I follow the Doom9 guide, it seems to be pretty basic GOP settings, and it is just a bit off still... I tried close all GOPs, but that made it worse.

[MITSUI_1]

This isn't really a bitrate viewer "bug", per se, but you do need to be aware of it.

So far as I can tall, when fed 24 fps material that has had rff and tff flags added so as to be telecined at playback, the bitrate viewer is not giving you the numbers for the ACTUAL 24 fps stuff on the disc, but rather, for the "effective" bitrate of the telecined output. (The effective bitrate will be higher, by about 20%).

Keep that in mind.

[nad]

Well, I am not gonna be opening 24FPS material with bitrate viewer..

The guides say to open the first VOB in Bitrate Viewer to get the Video information.. That is a 29.97fps material.



I am just mainly wondering about why and whether or not Bitrate Viewer shows the correct information all the time... As I said earlier some of the frame type readings are the opposite of what most of the movie really is.

I have also read issues with checking or unchecking upper field first? Can I trust Bitrate Viewer for this setting... Or does it sometimes have the wrong information. I think I remember people saying something about bitrate viewer giving wrong info for this setting... I think.

How would I be able to tell, or what symptoms on the final project would show incorrect video information selected in the CCE video configuration???

[adam]

Originally posted by nad
Well, I am not gonna be opening 24FPS material with bitrate viewer..


If your source is an ntsc dvd then yes you are, at least the vast majority of the time.

Almost all commercial ntsc dvds store the content at the original framerate of 24fps (23.976? not sure.) The dvd contains rff and tff flags which tell the dvd player to do a real time telecine to 29.97fps. This way the dvd contains %20 less frames which yields %20 more bitrate to work with, yet you still get the 29.97fps playback speed required by the ntsc standard. This is the same principle used in svcds when you encode progressively at 23.976fps and use the 3:2 pulldown.

So as MITSUI_1 suggested, your vobs are stored at 24fps but bitrate viewer is analyzing them at 29.97fps, which is why it will say it is interlaced.

If you are going to be keeping your svcd progressive I really don't see any point in using bitrate viewer to analyze your vobs before encoding. It really seems to me that the information you need will be found out anyway during your setup of the frameserving.

Basically your either going to use forced film in dvd2avi if applicable (%95 or higher film) or you are going to use an inverse telecine filter while frameserving. Either way you KNOW your encoder is being fed progressive frames. So if this is your encoding process then yes, always select progressive in cce.

According to the cce manual progressive sources will be higher quality with zigzag scanning order and interlaced sources will be higher quality with alternate scanning order. So again, if all you use are progressive sources then you need to always use zigzag scanning order.

As for the field order, if your source is progressive I don't think it matters whether you have upper or lower field first set. This seems to be case from my experience.

I think that pretty much covers the video settings, as the others seem self explanatory. As for the quantization scale, do as the cce manual states and always use non-linear unless you have a specific reason to use linear.

As for GOP settings, I don't think I can be much help, though the cce manual might.

[nad]

I understand now... Thanks.

Also, I am not making SVCDs, that is why I use Bitrate Viewer... I am creating a DVD compliant video VOB set to be burned onto a DVD-R disc....


I follow Doom9s CCE and IFOedit guide... Bitrateviewer is involved. Some of the things suggest are different from what you said... Like Doom9 suggests to use Linear Quanitizer scale even if bitrate viewer doesn't specify it.. I wonder also if the field order is important when we are talking about DVDs and not SVCDs...

Ok, you said bitrate viewer is reading at 29.97 fps.. So does that mean that when I set "Forced FILM" and then encode with CCE, I am not setting the bitrate for the effective output???? And that means that setting a maximum bitrate in CCE of 9800 would produce an effective bitrate outside of DVD specification? And that is probably why I get a "bitrate too high" error in Scenarist?

[adam]

Originally posted by nad
I understand now... Thanks.

Ok, you said bitrate viewer is reading at 29.97 fps.. So does that mean that when I set "Forced FILM" and then encode with CCE, I am not setting the bitrate for the effective output???? And that means that setting a maximum bitrate in CCE of 9800 would produce an effective bitrate outside of DVD specification? And that is probably why I get a "bitrate too high" error in Scenarist?

Bitrate means bits per second. It does not matter how many frames are being played during that second, your bitrate is still the same. The fact that encoding at 23.976fps means you have %20 less frames just means that every second that bitrate is having to encode less frames, which results in higher quality. If you are getting spikes in your bitarte above the standard allowed thats probably just the nature of vbr encoding. I don't think any encoder can perfectly respect your max bitrate settings. Most of the time these spikes don't cause playback problems though.

Sorry, I just assumed you were making svcds since this thread was under the vcd & svcd forum. I have no idea whether linear or non linear is better for dvds, I was just quoting the cce manual.

No I do not think the field order setting matters if you are using progressive input, regardless of what you are creating ex: svcd or dvd. If your source is progressive then there are no fields at all so this setting does nothing.