Re: meta-data in the VTT file header, a strawman proposal

On Apr 20, 2012, at 14:22 , Silvia Pfeiffer wrote:

>> 
>> Note that ]] on a line by itself is pretty rare, even in a wiki, no?  That's the only case that needs escaping;  ]] on a line by itself, and blank (and for safety, apparently blank) lines.  Otherwise, the text goes through unmodified.  So lines containing ]] are fine.
>> 
>> Since we're talking about existing implementations, this is almost exactly what SMTP uses for the body of a mail message, though there the terminator is a period (".") on a line by itself, and the blank line problem does not arise.
>> 
>>> In my opinion the changes required to introduce white-space characters
>>> at the beginning of a line are less intrusive than having to introduce
>>> an escaping mechanism.
>> 
>> 
>> Oh, so far I think the reverse.  822 requires a method to indicate true hard line breaks, for attribute values that need them, and that's an extension to 822.  For any common body of text with a number of lines that are empty or start with a non-blank character, all those lines need modifying, whereas an SMTP-like terminator syntax only needs to modify lines that look like a terminator and blank lines, which is a lot less in common cases.  A terminator-and-escape syntax ensures exact recovery of the original input, whereas with 822 one cannot tell the difference between lines that originally started with a blank, and lines that had one added for 822 compatibility.
> 
> 
> OK, Glenn and you've made me see the problems with 822 - indeed we
> would need some changes.
> 
> But the "[[" and "]]" proposal is soo ugly and not used anywhere else.
> I would be surprised if we couldn't find a solution that is being used
> elsewhere.


As I say, it's essentially what is used for mail message bodies in SMTP, plus the minimum extra needed for our application (blank-line suppression).  Maybe there is an existing system like this that includes blank-line management;  anyone think of one?

(I'll leave alone the aesthetic question!)

David Singer
Multimedia and Software Standards, Apple Inc.

Received on Friday, 20 April 2012 05:41:09 UTC