At 18:47 +0200 2/06/05, Chris Lilley wrote:
On Thursday, June 2, 2005, 6:32:45 PM, Ned wrote:
Thanks, but now I am lost. Why is this a 'video' stream and not a 'text' stream, then?
NF> Presumably because the intent is to display this as video. The rules for what NF> can fit under video are pretty loose; this is certainly an acceptable use of NF> the video top-level type. Text, OTOH, is usually thought of as a series of NF> lines and not as a stream of characters.
Text is certainly a sequence of characters, which may or may not be preformatted into 'lines'. Other characteristics of text are that spell-checking and translation to a different language are reasonable things to do with it.
Whether the text/* top level type is like that is another matter again, of course; that type having sufficient problems that it should really not be used for anything much beyond text/plain; charset=us-ascii.
NF> My (incorrect) understanding was that video was an unacceptable choice due to NF> SDP constraints. Without that constraint I would have been pushing for this NF> to go under video from the beginning.
Timed text, because of its time dependent nature, is an arguable fit for video (but something of a stretch).
There is probably a need for a more reasonably defined top level type, like textual/* or something, but the timescales and amount of effort to establish such a thing are non-negligible.
Thanks guys. This is clearly a sticky area, and as you say, timed text is presumed to be visually presented (though I guess it could be read aloud) so I guess 'video' is OK. I suspect that the true distinction lies in considering presentation; 'text' types should be presentable by a text-to-speech system (for the vision impaired, for example), whereas 'video' would not be expected to be capable of this. This in turn would suggest moving back to 'text' here, but only if the rules and maybe name of the 'text' type were clarified, and I agree that that is a long road to hoe. I rest my case, let video rule (though I still doubt its true correctness). -- David Singer Apple Computer/QuickTime