Spot consistency in subtitle file

wolfgangw / backports

Deep inspection of digital cinema packages

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Spot consistency in subtitle file #27

Open liloneum opened 11 years ago

liloneum commented 11 years ago

Time code in a subtitle file has to follow the spot numbering.

e.g.

<Subtitle SpotNumber="100" FadeUpTime="5" FadeDownTime="5" TimeIn="00:10:00:000" TimeOut="00:10:05:00">
  <Text VPosition="8" VAlign="bottom" HAlign="center" Direction="horizontal">Penultimate subtitle</Text>
</Subtitle>
<Subtitle SpotNumber="101" FadeUpTime="5" FadeDownTime="5" TimeIn="00:00:00:000" TimeOut="00:00:05:000">
  <Text VPosition="8" VAlign="bottom" HAlign="center" Direction="horizontal">Subtitle generated by mistake by the subtitle editor</Text>
</Subtitle>

wolfgangw commented 11 years ago

Lilian, thanks for the feedback. Actually, in TI's Subtitle Specification no mode of temporal ordering is specified. It was probably an inadvertent omission, though. S428-7, on the other hand, explicitly asks for a temporal stack (my word) where TimeIn shall be equal to or greater than the corresponding value in a preceding spot.

Allow me to think a bit about it. I am leaning towards a temporal sequentiality check, of course.

liloneum commented 11 years ago

OK. So why not just a hint for TI's Subtitles. You're right, subtitles are displayed not matter the order. For S428-7, I think the mxf will not be wrapped if it does not respect the rules...

wolfgangw commented 11 years ago

Because of the lack of specification the various implementations in the field might well be treating out-of-order subtitles differently. On which system did you test?

liloneum commented 11 years ago

I tried it on easydcplayer. I'll try it on a server as soon as it is possible.