W3C home > Mailing lists > Public > w3c-wai-ig@w3.org > October to December 1999

Re: SMIL Validation

From: geoff freed <geoff_freed@wgbh.org>
Date: 21 Dec 1999 09:39:14 -0500
Message-ID: <-1266353351geoff_freed@wgbh.org>
To: <w3c-wai-ig@w3.org>, Bruce Bailey <bbailey@clark.net>, <w3c-wai-ig-request@w3.org>
CC: "'Web Accessibility Initiative'" <w3c-wai-ig@w3.org>
Hi, Bruce:

It *IS* possible to write a valid SMIL presentation and play it using the G2 (and the RealPlayer 7).  I don't want to spread untruths, so I'm sorry for the misunderstanding.  However... when it comes to adding text to the presentation, things change.  SMIL has no standard markup language for text presentation, so RealNetworks created their own-- RealText.  (By the way, Oratrix has just released a version of GRiNS that will play RealText files, too.)

As far as I know, it isn't possible to download a streamed SMIL presentation (unless you present the files in downloadable manner, like a zip file).  The whole idea behind streaming files is that downloads are rendered unnecessary; this obviates rights problems and media theft, among other advantages (I do know that RealNetworks presentations can be coded to allow the user to record onto a local drive, but I haven't seen any examples of this yet).  

Re an example of a SMIL presentation without video:  since you already have a copy of CAR.SMI and its associated media files, just replace its <layout> section with the one below:

  <layout>
   <root-layout background-color="black" height="60" width="250"/>
   <region id="textregion" top="10" left="-37" height="120" width="250"/>
  </layout>

Save the .SMI file and play it with the G2 or RealPlayer 7, and you will see the CAR clip without a video region but with captions in English or subtitles in German (if you change the language specification in the preferences menu).  Is this the kind of thing you're looking for?  If not, let me know.

I'll have to spend some time reviewing the validation report; thanks for giving me the URL.

Geoff Freed
WGBH/NCAM



On Monday, December 20, 1999, Bruce Bailey <bbailey@clark.net> wrote:
>Geoff --
>
>I really did know that RealPlayer and SMIL were *not* the same think, but I 
>assumed that G2 got it *right* -- but from what you write it sounds like we 
>are in the good-old-bad-days like with Netscape and HTML 2.0!
>
>Are you saying that it is not possible to write a SMIL file that follows 
>the W3C specs that also works as intended with RealPlayer?
>
>I am using the files contained in car.zip and elev1.zip posted at your site 
>from URL:
>http://www.wgbh.org/wgbh/movies/
>
>I have no way to confirm it with any certainty, but the "live" files are 
>hosted by the Able channel at URL:
>http://www.tvontheweb.com/channels/able/
>
>From what (little) I know, one CANNOT download "live" SMIL files, even 
>though they are plain ASCII text.  (This is true of the binary RealMedia 
>files too.)  One would think that there is some clever way around this. 
> Anyone on this list know the trick?  The files don't seem to be kept in 
>the browser cache either.  Personally, I would MUCH rather just download  
> the RealMedia (.rm) files (and play them offline), but I think keeping the 
>source out the hands of the users is one of the products
>"features".
>
>I have mirror the files on my agency's site.  I don't have the RealPlayer 
>server software/hardware, so the files are just raw.  You can't play them 
>(you'll get an error message), but they will download.  It would be nice if 
>NCAM did this (hint, hint), especially since the audio and video tracks 
>don't compress much (having the files in a single archive is
>nice though).
>
>The SMIL validation report can be found (for the time being) at URL:
>http://validator.w3.org/check?uri=http://www.dors.sailorsite.net/ncam_sm  
>il/car.smi
>
>Geoff, you are in a position better than anyone to answer the question that 
>got me started with this.
>	Given a RealAudio file (like cardescen.rm) and captions (say, for example, 
>carcapsen.rt), what does the WORKING .smi text file look like that plays 
>WITHOUT a "videoregion"?  (Or at least the minimum size
>necessary.)
>
>Thank you.
>
>-- Bruce
>
>
>On Monday, December 20, 1999 1:56 PM, geoff freed 
>[SMTP:geoff_freed@wgbh.org] wrote:
>> Hi, Bruce:
>>
>> I am curious to know what CAR file you used as a source, as there are a 
>couple available.  Also, there is at least one kludge built into the 
>CAR.SMI file:  the textregion contains a negative number:
>>
>> <region id="textregion" top="135" left="-37" height="120" width="250"/> 
></layout>
>>
>> which is necessary due to a bug in the G2 Player's ability to center text 
>properly.  This will definitely screw up a validation report.  Can you send 
>me the report?  Thanks.
>>
>> FYI, the text file used for the captions is a RealText file, which is 
>proprietary to RealNetworks.  That will also not validate properly.
>>
>> Geoff Freed
>> WGBH/NCAM
>
>
>
Received on Tuesday, 21 December 1999 09:38:14 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 19 July 2011 18:13:46 GMT