Weird DVD playback: sound/picture different scenes!

[Cudzoziemiec]

We were watching Ice Age on the laptop using my son's account, which has "parental controls" ie a time limit. On reaching the time limit he was automatically logged out but the disc carried on playing - we could hear the soundtrack but not see the picture. So we logged into another profile, with the soundtrack going in the background all the time, and opened the DVD again - and it started playing from the beginning but the soundtrack had never stopped. So we had the opening credits rolling with the soundtrack playing from a scene later in the film! What's going on? How does it manage to play what seems like two scenes simultaneously?

[SteveC]

I'm not sure about this, but aren't the sound and the picture separate files, so you can have different versions on the same DVD? (E.g. the Lord of the Rings extended edition ones have different commentaries over the same pictures and I'm fairly sure you can get different languages on the same DVD.

S

[tonycollinet]

Sounds like you've got two instances of the DVD program playing separately in two different accounts, both accessing the same DVD.

[Cudzoziemiec]

I guess so - as you say you can definitely get many languages on one DVD as well as "director's commentaries" (and actors' commentaries, camera operator's commentaries, etc... Brings back the joyous days of my work in subtitling!) You can also get different "layers" of picture files so that you get subtitles in the chosen language. So different files, yes, but normally they all play in sync.

[Cudzoziemiec]

I guess what would have been really weird would have been if we'd had two pictures and/or two soundtracks opening simultaneously!

[Feanor]

I guess so - as you say you can definitely get many languages on one DVD as well as "director's commentaries" (and actors' commentaries, camera operator's commentaries, etc... Brings back the joyous days of my work in subtitling!) You can also get different "layers" of picture files so that you get subtitles in the chosen language. So different files, yes, but normally they all play in sync.

The different languages , director's commentaries etc are not different files.
They are different streams, contained within the same 'container' file.
As are the subtitles.
Some of the subtitles are 'forced'; so they always display even if the user has not selected any ( eg when elves speak in LOTR ).

[Cudzoziemiec]

I don't know much at all about the technological side of it, but when we made subtitles of principal photography (by which we meant text that's important to the plotline and is physically in the scene, so has to be translated) we used to call it a 'forced file'. It may well strictly be a stream rather than a file though.