Delay or no delay?

[BansheeX]

I've been ripping a lot of my DVDs to my HD and am trying to get as archival quality as possible. Yesterday, I noticed something odd being reported by mediainfo on files made by MakeMKV on my Batman TAS discs. This is what the audio section looks like:

Code: Select all

Audio
ID                               : 2
Format                           : AC-3
Format/Info                      : Audio Coding 3
Codec ID                         : A_AC3
Duration                         : 22mn 20s
Bit rate mode                    : Constant
Bit rate                         : 192 Kbps
Channel(s)                       : 2 channels
Channel positions                : L R
Sampling rate                    : 48.0 KHz
Video delay                      : -75ms
Stream size                      : 30.7 MiB (4%)
Title                            : 2/0
Language                         : English

There is a -75ms video delay attribute that mkvtoolnix won't produce rebuilding the same data. I dug around the internet and found this:

http://www.mpucoder.com/guides/delaymyth.html

I don't know which behavior is right, I just thought I'd point out something I thought was suspicious in case it was a bug in the way you interpret VOB data.

[setarip_old]

Hi!

Do the files created by MakeMKV play back properly (in synch)? That's really all you need to be concerned with...

[BansheeX]

I can't really discern any appreciable playback difference in this case, but it could produce more noticeable problems in other discs. I don't have thousands of discs to test with, so it might be worth a proactive fix (if indeed it is a bug).

Another strange difference that seems somewhat cosmetic on the surface is that Makemkv gives the video data a "BVOP = Yes" tag and that same data rebuilt with mkvtoolnix gives the video data a "BVOP = No" tag. I know the tag is related to a frame type, but I have no idea how or if it influences playback.

[mike admin]

There is no such thing as "audio or video delay" in MKV, in MKV every frame is timestamped. Try a test - put both files through any remuxer, like mkvtoolnix, and you will get identical output.

[BansheeX]

So then what's the explanation for why a MakeMKV-built file reports video delay in MediaInfo and a mkvtoolnix-built file doesn't? The reports should be identical because the data being handled is the same. If indeed the playback is identical, then there's still the issue of one these file's spitting out false and confusing attributes.