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Difference between revisions of "Timed track formats"

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* http://service.real.com/help/library/guides/realtext/realtext.htm
 
* http://service.real.com/help/library/guides/realtext/realtext.htm
  
Supports a number of features that aren't necessary. Uses "<br/>" for line breaks. Could probably be used as the basis for a new similar format.
+
Supports a number of features that aren't necessary. Uses "\<br/>" for line breaks. Could probably be used as the basis for a new similar format.
  
 
== SAMI (.smi) ==
 
== SAMI (.smi) ==
 
* http://en.wikipedia.org/wiki/SAMI
 
* http://en.wikipedia.org/wiki/SAMI
  
Probably has complicated legacy parsing requirements. Uses "<BR>" for line breaks. Would be difficult to extend in a backwards-compatible way.
+
Probably has complicated legacy parsing requirements. Uses "\<BR>" for line breaks. Would be difficult to extend in a backwards-compatible way.
  
 
== Structured Subtitle Format (.ssf) ==
 
== Structured Subtitle Format (.ssf) ==
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* http://blog.aegisub.org/2008/07/universal-subtitle-format-post-mortem.html
 
* http://blog.aegisub.org/2008/07/universal-subtitle-format-post-mortem.html
  
Extremely verbose. Uses "<br/>" for line breaks.
+
Extremely verbose. Uses "\<br/>" for line breaks.
  
 
= Other formats =
 
= Other formats =
  
 
CMML and SMIL are not listed above since they don't appear to be subtitle formats so much as timed media mixing formats.
 
CMML and SMIL are not listed above since they don't appear to be subtitle formats so much as timed media mixing formats.

Revision as of 01:27, 27 April 2010

Lists of formats:

Requirements:

  • We need to use time for timings, not frames, because the same file might apply to multiple versions of the same video, with different frame rates.
  • For a similar reason, any positioning needs to be relative to the frame, not absolute (in pixels)

(Extensions marked * below are shared by multiple formats.)

AQTitle (.aqt)

Uses frames for timings.

JACOSub (.jss)

Pretty complicated. Uses "\n" for line breaks.

Kate

Binary format with text components, making it hard to hand-edit. The text components seem pretty verbose.

MicroDVD (.sub*)

Uses frames for timings. Uses "|" for line breaks.

(Appears to be basically the PowerDivX format, but using seconds instead of frames.)

MPEG-4 Timed Text (.ttxt)

Pretty complicated. Seems to be formatting-centric. Has some pixel-based positioning. Difficult to hand-edit. Uses strings delimited by apostrophes to mark line breaks.

MPSub (.sub*)

Relative timings, which can be hard to hand-edit correctly. Uses real line breaks. Could be extended, though most useful extensions would not be backwards-compatible (e.g. adding a new timing format).

Ogg Writ

Binary format, nigh on impossible to hand-edit.

Phoenix Subtitle (.pjs)

  • No spec or demo file found

Uses frames for timings according to wikipedia.

PowerDivX (.psb)

Currently has low resolution timings. Uses "|" for line breaks. Simple format. Could be extended usefully.

(Appears to be basically the MicroDVD format, but using seconds instead of frames.)

RealText (.rt)

Supports a number of features that aren't necessary. Uses "\
" for line breaks. Could probably be used as the basis for a new similar format.

SAMI (.smi)

Probably has complicated legacy parsing requirements. Uses "\
" for line breaks. Would be difficult to extend in a backwards-compatible way.

Structured Subtitle Format (.ssf)

Couldn't find any information on this format.

SubRip (.srt)

Currently has pixel-based positioning. Simple format. Uses real line breaks. Could be extended usefully.

Gloss Subtitle (.gsub)

Couldn't find any information on this format.

SubStation Alpha (.ssa)

Pretty verbose. Has some pixel-based positioning. Uses "\N" for line breaks (though this is somewhat configurable). Has some rather subtle syntax of the kind that typically results in buggy implementations. (Indeed, see the "note" in [1].)

Advanced SubStation Alpha (.ass)

Even more complicated version of SubStation Alpha.

SubViewer (.sub*)

Simple format. Uses "[br]" for line breaks. Could be extended usefully.

Universal Subtitle Format (.usf)

Extremely verbose. Uses "\
" for line breaks.

Other formats

CMML and SMIL are not listed above since they don't appear to be subtitle formats so much as timed media mixing formats.