MakeMKV creates off spec chapters

[ndjamena]

I've just been helping the maker of MetaX debug the programs new MKV abilities as it's been having problems with chapters. I finally figured out that final hurdle was being caused by MakeMKV failing to supply End Times to the chapters. He's not pleased because that goes against Matroska specifications. Essentially MetaX has been determining Chapter duration by subtracting the starting time of a chapter from the ending time, which with MakeMKV files always results in a duration of negative starting time. The fix would be to assume the end times of a chapter to be the start time of the next chapter but since Matroska supports ordered (non-consecutive, non-contiguous) chapters it would not be proper to do that and so he's asked me to post on this forum complaining. Please consider fixing this in a future update.

I hate being this...

Have fun!

ndjamena

[Romansh]

I'd have to check but IIRC HandBrake does the same. At the very least, mkvalidator does not complain about this.

If I read the MKV spec. correctly, the element is not mandatory anyway: http://matroska.org/technical/specs/chapters/index.html

[ndjamena]

From: Dan Hinsley
Sent: ?7? ?January? ?2013 ?7?:?46? ?AM
To: 'N'Djamena Darkwoods'
Subject: RE: MetaX MKV

There’s just one problem with this. How am I supposed to figure out the duration of the last chapter given just the last start time? That’s why the MKV standard says to have both. I don’t suppose there’s any way to get MakeMKV fixed to actually do the correct thing? Since I started with MP4’s, that’s why duration is the prime driver. I can deal with everything but the last chapter issue in a hack way, but it’s not clean.

Looks like MakeMKV is open source, so maybe you could post on their website and see if they would include the end time for chapters?

Dan

***I have nothing to actually say on the topic***

Code: Select all

From: N'Djamena Darkwoods [mailto:ndj@live.com.au] 
Sent: Sunday, January 06, 2013 5:04 PM
To: Dan Hinsley
Subject: RE: MetaX MKV

It’s possible, but it won’t help with the countless MKVs that have already been made with MakeMKV.  I’ve loaded my MetaX Angel MKV into the MKVMerge Chapter editor again and the End Times are exactly the same as the Start Times of the next chapter...  Theoretically the end time of the last chapter should be the running time of the video itself...  Of course that’s assuming consecutive chapters, and I’m aware the MKV container supports non-consecutive chapters - so maybe if the program finds blank end-times consecutive could be assumed.  Oh, here’s a thought, maybe if it finds zero ending times MetaX could ask if it should fix them???  I’ll go make an account for the MakeMKV forum now...

[ndjamena]

On second thought I will say one thing. On the DVDs Star Blazers and Tekkaman Blade reuse the same title sequence and Closing Credits for each episode ie the title sequence is chapters 1, 5, 9 and 13. Without end times each time the title sequence was replayed it would also replay all the episodes so far until it reached the next chapter. That example may not seem directly relevant but there are situations where end times are absolutely vital. I don't have the MKV spec in front of me and now I've been told two different things by two different developers.

P.S. MakeMKV just cut out all but one instance of the title sequences and Closing Credits. I had to use MKVMerge to knit the episodes back together again which was a PITA actually. At least Handbrake and MKVMerge don't have that particular feature in common.

P.S.S. Hang-on, am I complaining? I adore MakeMKV and I really didn't think anything about having to recreate the Star Blazers/Tekkaman Blade episodes. Actually it's kinda fun. If everything worked perfectly it'd get kinda boring doing the same thing over and over again... Problem Solving, that' what life's about!!!

I'll shut up now.

[fryk.]

Simply set the last chapter's end time to the end time of the longest video / audio track.

[ndjamena]

*sigh* Not my battle.

[bitfidelity]

I'm curious if this has anything to do my current problem. When I jump to certain chapters, there will be corruption/blocking in the first frame of the chapter.

Initially I thought MakeMKV was screwing something up in the muxing process, but I tried an MKV made using mkvmerge and I ended up with the same problems, though at different chapter marks.

[mike admin]

What you describe is probably a playback error. Is the codec VC-1?

Also, just to make sure, the original bug was fixed quite a long time ago - MakeMKV now always sets proper start and end times for chapters, and it also ensures that chapter start times point to an I-frame.