Chapter timestamp

[abel413]

Hi,

I add some talks in the forum regarding Chapters which are not recognized properly sometimes (e.g. they start too quickly including extra mili seconds from previous scene). Actually, I noticed that chapters appear on MakeMKV with following format : h:mm:ss, like for example 0:03:40. But after demuxing manually chapters from the BluRay it appears correct timestamp is 00:03:40.7622000 e.g. h:mm:ss.xxxxxx.

So I guess these extra decimals matters and can explain the issue. So what I want to know is whether these decimals are cut or rounded by MakeMKV ? If yes, do you think an evolution could be implemented to keep them so as to display correct chapters ? If no, then, is there a particular reason to explain my issue ? Honestly, it is almost clear that starting at 0:03:40 instead of 00:03:40.7622000 can result in seing a very few unexpected frames from previous scene while current chapter scene starts.

[abel413]

So isn't there any MakeMKV developer to help ?

[Woodstock]

The MakeMKV developer is Mike, and he isn't here every day.

[abel413]

Do you mean there is only 1 developper ?

[Woodstock]

As far as any of us have been able to tell, Mike is the only developer. He hasn't said anything publicly to confirm or deny that, but I haven't seen "developer-level messages" from anyone other than him in all the time I've been on this forum.

There are a few people on the forum here that are much more familiar with the intricacies of how things are stored in MKV files than me, that might know the answer to your timestamp question, though.

[abel413]

Actually my concern was much more to know whether they can do such an evolution e.g. take mili seconds in account. Else we will often have wrong chapters as they will start too early in many cases.

[Woodstock]

Not sure anything needs to be added - it looks like a limitation in the tool you used to view the chapter information:



As you can see, chapter timing is already stored to fractions of a millisecond.

[abel413]

Hmm well perhaps these mili seconds are taken in account in spite of the fact they are not displayed. Why not ? But then somewhere backside the values are rounded. If that is true it would be absurd : why would they 'edit' chapter file ? It should just be muxed untouched. It looks logical to me.

[Woodstock]

I'm still of the opinion that this issue comes down to disk authoring. I've seen this primarily in disks that are authored as one large file with all episodes (Bleach, Ah My Goddess, etc.) vs. separate files per episode with an all-encompassing play list for those episodes (some NCIS seasons, some Doctor Who seasons).

The all-in-one-file disks do not guarantee a key frame at what would be the chapter boundary, but the individual files version will always have an initial key frame to start the file.

[abel413]

Hmm well if I copy full bluray to computer then open m2ts with adequate mpls file for chapters and information and finally remux movie to mkv with MKVToolnix there is no problem. So it is clear something is done wrong by MakeMKV. In my cases it is almost always the case with movie but it does not happen with bonus extracted (making of, cut footage...). I dont think my blurays are all in one as I systematically have one m2ts for the movie, one for making of ect