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

On Wed, Apr 11, 2012 at 6:12 AM, David Singer <singer@apple.com> wrote:
>
> On Apr 10, 2012, at 1:37 , Silvia Pfeiffer wrote:
>
>> On Tue, Feb 28, 2012 at 4:39 AM, David Singer <singer@apple.com> wrote:
>>>>
>>>> Message-Header style gives us another way to escape continued lines,
>>>> which is to indent them with whitespace. This isn't any harder
>>>> programmatically, but is easier to read. (You did it anyway in your
>>>> example!) Might be more confusing to debug blank line escapes though.
>>>
>>> Yes. I also toyed with SMTP-like multi-line (no opening bracket, and the end is a period on a line by itself), but I don't think that's so easy to read, visually, and seems more error-prone.  Few people read SMTP input; people do expect to read VTT files.  I am guessing that for many cases, no escaping at all will be needed (']]' on a line by itself is pretty unlikely in CSS, as are lines starting with \, and stylesheets don't need to have blank lines).
>>>
>>>>
>>>>> Examples:
>>>>>
>>>>> kind=captions examplecompany-test = for steve
>>>>> initialTStimestamp=162642774
>>>>> stylesheetURL=http://www.example.com/vtt-plain.css stylesheet=
>>>>> [[ p { font-size: 100px; } \ p::first-line { background:
>>>>> url(http://www.w3.org/StyleSheets/TR/logo-REC) no-repeat;
>>>>> font-size: 10px; span { border-left: solid 1em black; } } ]]
>>>>> srclang=en-US label=Zeroes for King!
>>>>
>>>> My suggestion would look like:
>>>>
>>>> Kind: captions
>>>> X-examplecompany-test: for steve
>>>> Timestamp-offset: 162642774
>>>> StylesheetURL: http://www.example.com/vtt-plain.css
>>>> Style:
>>>> p { font-size: 100px; }
>>>>
>>>> p::first-line {
>>>>   background: url(http://www.w3.org/StyleSheets/TR/logo-REC) no-repeat;
>>>>   font-size: 10px;
>>>>   span { border-left: solid 1em black; }
>>>> }
>>>> srclang: en_US
>>>> Label: 𝟎s for 王!
>>>>
>>>
>>> what terminates the block, in your syntax?
>>
>> A line that starts without white space is not part of a block,
>> according to RFC822 (it's called "folding").
>
> RFC 822 defines clearly that everything after the first null line is the message body, not headers, so your example would have us treating

We're just parsing RFC822-style headers, not a full message. I
wouldn't want to use the full RFC822 parser!


>
>  p::first-line {
>  background: url(http://www.w3.org/StyleSheets/TR/logo-REC) no-repeat;
>  font-size: 10px;
>  span { border-left: solid 1em black; }
> }
> srclang: en_US
> Label: 𝟎s for 王!
>
> as cue-text :-(.  Or am I missing something?  That's also the case in the current VTT spec (that the header lines terminate on the first blank line).
>
> RFC 822 generally considers values as "one long line that can be folded if it's too long", and I am not sure that's right for us.   I think that line-breaks can be significant in some of the values we cant, no?  (Such as CSS).

Do we need empty lines?


> On my reading of 822, I think this example would have to be:
>
> Kind: captions
> X-examplecompany-test: for steve
> Timestamp-offset: 162642774
> StylesheetURL: http://www.example.com/vtt-plain.css
> Style:
>  p { font-size: 100px; }
>  p::first-line {
>   background: url(http://www.w3.org/StyleSheets/TR/logo-REC) no-repeat;
>   font-size: 10px;
>   span { border-left: solid 1em black; }
>  }
> srclang: en_US
> Label: 𝟎s for 王!

Yeah, I think that's correct.

Silvia.

Received on Wednesday, 11 April 2012 01:11:02 UTC