REQ: DVD2SVCD chapter handling

[Cokes]

dvd2svcd, can you include a better chapter handling in DVD2SVCD? :)

In example my procedure follows:

First, I have 1 DVD with 18 chapters and I would to store first 9 chapters on CD1 and last 9 chapters on CD2.
So I start DVD2SVCD, set all settings as I want - except some things at Video processing, where I consciously want to use quicker progress (anyway I don't need it):
I set no TemporalSmoother, SimpleResize and CBR mode in CCE, no CD overlapping and mux start at 0.
Fire up conversion and wait until the muxing of subtitles is done. Then I start to customising the video settings:
I edit avs file (add TemporalSmoother and replace BicubicResize) and I take ChapterXtractor and look to chapter frames.
I include these chapter frames in CCE's ECL file, i.e.:
chapter=0:
chapter=1053:
chapter=6500:
chapter=11674:
chapter=18304:
chapter=24869:
chapter=34450:
chapter=40599:
chapter=49556:
chapter=54379:
chapter=66651:
chapter=76128:
chapter=80353:
chapter=87997:
chapter=96044:
chapter=105170:
chapter=112255:
chapter=116181:
Then I edit encode_first=0 and encode_last=54378. Calculate bitrate, encode first CD videostream (VBR 4-5 pass, filtering), again edit encode_first=54379 and encode_last to last frame and encode last CD videostream. So I have 2 mpv's.
Audio part: decoding 1 big wavfile with BeSweet, again frame based cut in TMPGEnc (with toolame encoding) > 2 mp2's.
Muxing in bbMPEG, rename it to bbMPEGmuxedfile01 (or so, you sure know, what I'm talking about) and fire up DVD2SVCD from muxing subtitles (thus because I need new SUB file calculation - time and size of my MPG's have changed).
For authoring I use VCDEasy and ChapterXtractor.

Could you think over if you can take in some of these features in next version of DVD2SVCD? This would be great... :cool:

[oliv]

Hello Cokes,
can it all be summarized by "Cutting at the end of a DVD chapter"?

[Cokes]

Yes, we could call it so.

First I'd to say, that for right DVD frame based chapter cutting we need for CCE generated ECL with chapterpoints.

Second, the need of "x chapters fit to CD1. y chapters fit to CD2..." function (bitrate calculation).

Third, video-frame (i.e. for PAL - 40 ms) based cutting of audiostream - I think there's no way to cut mp2 stream without detailed knowledge of muxing. I mean WAV-based cutting would be easier (either output in WAV -> cut -> encode, or maybe DSPguru can help...?).

[gerti67]

Hi Cokes,

can be I didn't get the idea of what you really want to do with your method - but why don't you just use dvd2svcd's internal routines for ripping, load the desired IFO in "Conversion" tab and click on the "Movie length" pulldown afterwards, then just select the first 9 chapters (unselect the rest), close the "Select chapters" window, hit the "Go" button and let dvd2svcd do the rest? :confused: And then use the same procedure with the rest of the chapters afterwards.

Greetings,
Gerti

P.S. You only have to make sure to use 1 CD in "Bitrate" tab for the length of your selected chapters.

[Cokes]

Hi gerti67,

you're right, when I rip DVD with internal routines - this is a way, but what I miss in that moment is already chapter list in CCE ECL [file] section...

[markrb]

This has been brought up numerous times before and it is not as simple as you make it out to be. It would end up becoming two or more seperate encodes pretty much no matter what.
To be able to cut at chapters each disc would need to be processed seperately. Each with, most likely, different bitrate settings to force it to fit the cd. Chapter points are hardly ever at %50 of a movie and even if they were the inherent differences in sections of the video would cause the VBR bitrate to fluctuate causing the file size to be different then what is asked for.

If you want to chapter points at specific times then read the chapters file and edit the appropriate file manually.

Mark

[mkanar]

Sometimes there is a situation whereby 1 CD is not enough but with 2 CDs, the final disc cannot be filled up due to the max bitrate limitation of SVCD. This could also happen with 2&3 CDs of course.

In this situation, it would be 'nice' if the split could happen at a chapter end point (rounded up in seconds to a whole number second).

Also, this would be more complicated of course, but if a more-conservative bitrate was used (for example, a 730MB/CD target bitrate for encoding but an 810MB/CD true size), it would 'increase the probability' of being able to split the movie over 2 CDs.

Finally, my speculation, based on wasted hours that I have spent with TMPGEnc, is that TMPGEnc uses fairly consistant overall bitrate usage throughout a movie encoded with VBR-encoding. I am assuming the DVD2SVCD agrees somewhat since DVD2SVCD implemented the 1-pass VBR estimation strategy.

MKanar

[DDogg]

One of the things I have asked to be put in the future wishlist is frame accurate cutting so one could specify the exact frame for the disk transition.

We know many people like to "pick" a specific scene transition for the cut. The overlap feature was put in to make the cut a little less distracting, and for most people, it is just fine.

D2S said he would consider it, but it would be a serious amount of work for him and amounts to a rewrite of many routines.

That worries me a bit as the program is starting to really firm up and most of the critters have been swatted. As is obvious, I have mixed emotions. I would really like to see this feature but would hate to see stability lost.

[mkanar]

I haven't looked at the bbMPEG source code, so I don't really know how possible this is, but...

When using bbMPEG to both mux and then segment the video stream, there is of course the 'start time' and 'end time' arguments, which can be set to any integer value in seconds. I wonder how much code would need to be changed so that bbMPEG can accept floating point numbers instead of whole numbers/integers. I realize that this isn't as good as what you mentioned, DDog, but I thought that this might be a possible interim solution. (?)

Anyhow, thanks for the comments and words of wisdom!

MKanar

[markrb]

The hardest thing is not to be able to pick a point and cut at it using bbmpeg after the video has been encoded. If need be we could do that manually.
The hard part is trying to figure the bitrate and the cut point before the video is encoded to make it fit just right.
It is comparitively easy to do this after the video has been encoded, but before is very hard, especially with VBR.
It would be a great thing if it can be added.

Mark

[pacohaas]

there are 2 ways I could envision this happening:

Method 1:
1. do a complete encode, splitting at CD sizes
2. use the timecodes to see what chapter breaks are nearest to the cuts
3. re-encode each CD separately with a recalculated bitrate for each so you have full CD's

Method 2:

1. Let the user guess the results of steps 1 and 2 from method 1 and simply set their chapter cut points.
2. encode each CD with the appropriate bitrate