- From: Andreas Tai <tai@irt.de>
- Date: Wed, 17 Jul 2013 16:35:41 +0200
- To: John Birch <John.Birch@screensystems.tv>
- CC: "'nigel.megitt@bbc.co.uk'" <nigel.megitt@bbc.co.uk>, "'glenn@skynav.com'" <glenn@skynav.com>, "'public-tt@w3.org'" <public-tt@w3.org>
- Message-ID: <51E6ABBD.2060702@irt.de>
Yes, I think some informative guidance might be very helpful (if it was meant that way). To add a Non breaking Space in the TTML document, e.g. <span tts:backgroundColor="black" tts:color="white"> A subtitle on one line </span> is not a solution I would prefer, because it clearly breaks the separation of content and layout. What can be done for a specification that needs to define this presentation behaviour is the following: To state an normative prose what is defined in the YouView spec: "Where text with tts:backgroundColor is applied at the span level, the filled area shall extend the width of a space character to the left of the first rendered character on each line and to the right of the last rendered character on each line." In addition: an informative note how this could be achieved, e.g. with option B below - prefixing and suffixing with NBSP by the client(!). Actually for a specification that reference TTML 1.0 it make no sense to apply the tts:padding to a span - unless the fontSize is defined directly or indirectly as cell and the metric "c" is allowed for padding. The application to a p seems not to be needed anyway because this would be the same as the application of padding to the region where the p is contained. Best regards, Andreas Am 17.07.2013 11:16, schrieb John Birch: > A more palatable option might be to suggest this as a (temporary?) > implementation strategy... I.e. Specify that padding on a span is > allowed and should either be a) ignored or b) interpreted and > implemented in the client by prefixing and suffixing the text with > NBSP.... > > J > > > *From*: Nigel Megitt [mailto:nigel.megitt@bbc.co.uk] > *Sent*: Wednesday, July 17, 2013 09:50 AM > *To*: Glenn Adams <glenn@skynav.com>; Andreas Tai <tai@irt.de> > *Cc*: public-tt <public-tt@w3.org> > *Subject*: Re: Padding on tt:p and tt:span elements > > Agree that adding in spaces would achieve the desired appearance, and > might work as a short term fix for distribution purposes, but it is > not a good solution (or a solution at all) for archiving and other > processing: amending the text content of the TTML in order to fix the > appearance mixes two worlds that should ideally stay separate. Hence > the request to add padding to spans. > > > > > On 16/07/2013 20:45, "Glenn Adams" <glenn@skynav.com > <mailto:glenn@skynav.com>> wrote: > > > On Tue, Jul 16, 2013 at 12:31 PM, Andreas Tai <tai@irt.de > <mailto:tai@irt.de>> wrote: > > As a couple of TTML.next issues are discussed at the moment I > want to bring up the padding issue again. This is filed as > Issue 168. > > Currently it is hard to solve following requirement for > background colour fill that is defined in the Youview TTML > profile[1]: > > > Where text with tts:backgroundColor is applied at the span > level, the filled area shall extend the width of a space > character to the left of the first rendered character on each > line and to the right of the last rendered character on each > line. > > > One way to achieve this as a work around (in the near term) is to > use NBSP, EM SPACE, EN SPACE, THIN SPACE and so on, using > tts:wrapOption as needed to prevent line breaks. > > > If in TTML.next padding could be applied to a span: to what a > percentage value would relate to? In XSL 1.1 and CSS 2.1 it > relates to the width of the containing block [2]. So assumed > this will be the same definition in TTML, a span would be the > child of a p element and a padding value would be specified in > percentage for that span than it would be the width of that p > element? > > > Actually, the XSL-FO definition is based on the nearest ancestor > reference area, which is the block-container generated by > tt:region. So a percentage would be resolved according to the > contain region size. When we do map to CSS we will need to > translate to non-percentage values in order to avoid the distinct > CSS definition. > > This would be very similar to the current definition. In TTML > the percentage value for padding is defined as relative to the > width and height of the region. As the extent of a p is the > same as the extent of the region where it is contained the > width of the containing block is effectively the with of the > region. > > As the width of the region could vary this seems not a good > solution for the requirement defined by the Youview spec. > > The only possible solution to establish a relation between the > chosen font and the padding value seems to be the cell metric. > To emulate the width of a space the padding value of the start > edge for the first span in a line and the padding value for > the end edge of the last span in line could be set to 1c > (assumed that the font-size is 1c). Is there any more > intuitive solution? > > > Use NBSP. Any any case, 1c doesn't mean 1 EM unless fontSize is > defined as 1c. > > > Best regards, > > Andreas > > [1] > https://industry.youview.com/resources/YouView_Core_Technical_Specification_1.0.pdf, > page 120, Section 4.4.4.4 > [2] http://www.w3.org/TR/xsl/#padding-before > > > > > Am 24.05.2012 08 <tel:24.05.2012%2008>:33, schrieb Andreas Tai: >> For the EBU subset of TTML we have to include a change of the >> padding attribute in the version 1.0 to meet requirements of >> our target group. As understood a change that adresses Issue >> 168 (http://www.w3.org/AudioVideo/TT/tracker/issues/168) will >> be adopted in TTML earliest in 2013. Nevertheless it would be >> good that the wording in the EBU-TT spec is aligned with an >> expected change in TTML 1.1. >> >> The application of padding to p and span will be specified in >> the EBU-TT spec as follows: >> >> "Padding (or inset) space on all sides of a block area >> generated by a tt:p element or an inline area generated by a >> tt:span element. >> >> The padding property shall not be inherited." >> >> It would be great to hear your opinion. >> >> Best regards, >> >> Andreas >> >> >> Am 08.05.2012 22:27, schrieb Sean Hayes: >>> Hmm. I was sure I'd created an issue for this, but >>> apparently not. >>> >>> ISSUE-168 >>> <https://www.w3.org/AudioVideo/TT/tracker/issues/168> added >>> to database >>> >>> >>> ------------------------------------------------------------------------ >>> *From:* Andreas Tai [tai@irt.de <mailto:tai@irt.de>] >>> *Sent:* 08 May 2012 6:26 PM >>> *To:* Sean Hayes >>> *Cc:* Glenn Adams; John Birch; public-tt@w3.org >>> <mailto:public-tt@w3.org> >>> *Subject:* Re: Padding on tt:p and tt:span elements >>> >>> Will there be an entry in the tracker for this? >>> >>> In addition I attach an html-example that shows the wished >>> behaviour and a CSS definition that is similiar to the >>> needed TTML styles. >>> >>> Best regards, >>> >>> Andreas >>> >>> Am 25.04.2012 21 <tel:25.04.2012%2021>:56, schrieb Sean Hayes: >>>> >>>> While what you say is true it is very inconvenient from an >>>> authoring perspective, and if the user can set the font >>>> (which is a requirement of the FCC rules), then you need >>>> the region to be able to adapt. Better to use the <p> >>>> background which does adapt naturally. You can artificially >>>> introduce the padding using spans with preserved space, >>>> however this is a pretty ugly hack. I think it makes sense >>>> to allow padding on these elements. >>>> >>>> *John Birch | Strategic Partnerships Manager *|*Screen** >>>> *Main Line : +44 1473 831700 | Ext : 270 | Direct Dial : >>>> +44 1473 834532 >>>> Mobile : +44 7919 558380 | Fax : +44 1473 830078 >>>> John.Birch@screensystems.tv >>>> <mailto:John.Birch@screensystems.tv> | www.screensystems.tv >>>> <http://www.screensystems.tv> | >>>> https://twitter.com/screensystems >>>> >>>> *Visit us at >>>> SMPTE conference & exhibition, Stand G35, Sydney Exhibition >>>> Centre, Darling Harbour, 23-26th July* >>>> >>>> *P**Before printing, think about the environment* >>>> >>>> >>>> *From:*Glenn Adams [mailto:glenn@skynav.com] >>>> *Sent:* 25 April 2012 17:04 >>>> *To:* John Birch >>>> *Cc:* tai@irt.de <mailto:tai@irt.de>; public-tt@w3.org >>>> <mailto:public-tt@w3.org> >>>> *Subject:* Re: Padding on tt:p and tt:span elements >>>> >>>> On Wed, Apr 25, 2012 at 9:33 AM, John Birch >>>> <John.Birch@screensystems.tv >>>> <mailto:John.Birch@screensystems.tv>> wrote: >>>> >>>> You hit the nail on the head. Font size at authoring time >>>> is only true if font exists at browser... Otherwise >>>> substitution means all bets are off. >>>> >>>> not quite; you can always overestimate the size which >>>> permits containment without overflow >>>> >>>> Best regards, >>>> John >>>> >>>> *From*: Glenn Adams [mailto:glenn@skynav.com >>>> <mailto:glenn@skynav.com>] >>>> *Sent*: Wednesday, April 25, 2012 04:00 PM >>>> *To*: John Birch >>>> *Cc*: Andreas Tai <tai@irt.de <mailto:tai@irt.de>>; >>>> public-tt <public-tt@w3.org <mailto:public-tt@w3.org>> >>>> *Subject*: Re: Padding on tt:p and tt:span elements >>>> >>>> On Wed, Apr 25, 2012 at 5:22 AM, John Birch >>>> <John.Birch@screensystems.tv >>>> <mailto:John.Birch@screensystems.tv>> wrote: >>>> >>>> In TTML as I understand it(as a result of derivation >>>> from xsl:fo?), there is no possible mechanism that can >>>> *set* the region size as a result of a calculation of >>>> the *rendered* text size on the display. In contrast to >>>> broadcast practises, in TTML the text is fitted inside >>>> a predefined region (or overflows / clips), rather than >>>> the region (growing) fitting the text. >>>> >>>> it can, if the size can be determined at authoring >>>> time; but that will depend on font usage; so you are >>>> correct that if the font size is unknown, then you may >>>> have to overestimate the size, e.g., by using em or c >>>> length units >>>> >>>> *John Birch | Screen Systems | Strategic Partneships >>>> Manager* >>>> >>>> Main Line : +44 1473 831700 <tel:%2B44%201473%20831700> >>>> | Ext : 270 | Direct Dial : +44 1473 834532 >>>> <tel:%2B44%201473%20834532> >>>> Mobile : +44 7919 558380 <tel:%2B44%207919%20558380> | >>>> Fax : +44 1473 830078 <tel:%2B44%201473%20830078> >>>> John.Birch@screensystems.tv >>>> <mailto:John.Birch@screensystems.tv> | >>>> www.screensystems.tv <http://www.screensystems.tv> | >>>> http://twitter.com/ScreenSubtitles >>>> >>>> *SysMedia - Now part of Screen*......a fusion of >>>> expertise, a combination of World Leading Products >>>> >>>> *LAUNCHING SOON! *A new single website incorporating >>>> all Screen and Sysmedia products. >>>> >>>> *Visit us at >>>> Broadcast Asia, Block 4F3-01, UK Pavillion, Suntec >>>> Singapore, 19th - 22nd June 2012 * >>>> >>>> *P**Before printing, think about the environment* >>>> >>>> This message may contain confidential and/or privileged >>>> information. If you are not the intended recipient you >>>> must not use, copy, disclose or take any action based >>>> on this message or any information herein. If you have >>>> received this message in error, please advise the >>>> sender immediately by reply e-mail and delete this >>>> message. Thank you for your cooperation. Screen >>>> Subtitling Systems Ltd. Registered in England No. >>>> 2596832. Registered Office: The Old Rectory, Claydon >>>> Church Lane, Claydon, Ipswich, Suffolk, IP6 0EQ >>>> >>>> >>>> >>> >>> >>> -- >>> ------------------------------------------------ >>> Andreas Tai >>> Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH >>> R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR >>> Floriansmuehlstrasse 60, D-80939 Munich, Germany >>> >>> Phone:+49 89 32399-389 <tel:%2B49%2089%2032399-389> | Fax:+49 89 32399-200 <tel:%2B49%2089%2032399-200> >>> http:www.irt.de <http://www.irt.de> | Email:tai@irt.de <mailto:tai@irt.de> >>> ------------------------------------------------ >>> >>> registration court& managing director: >>> Munich Commercial, RegNo. B 5191 >>> Dr. Klaus Illgner-Fehns >>> ------------------------------------------------ >> >> >> -- >> ------------------------------------------------ >> Andreas Tai >> Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH >> R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR >> Floriansmuehlstrasse 60, D-80939 Munich, Germany >> >> Phone:+49 89 32399-389 <tel:%2B49%2089%2032399-389> | Fax:+49 89 32399-200 <tel:%2B49%2089%2032399-200> >> http:www.irt.de <http://www.irt.de> | Email:tai@irt.de <mailto:tai@irt.de> >> ------------------------------------------------ >> >> registration court& managing director: >> Munich Commercial, RegNo. B 5191 >> Dr. Klaus Illgner-Fehns >> ------------------------------------------------ > > > -- > ------------------------------------------------ > Andreas Tai > Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH > R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR > Floriansmuehlstrasse 60, D-80939 Munich, Germany > > Phone:+49 89 32399-389 <tel:%2B49%2089%2032399-389> | Fax:+49 89 32399-200 <tel:%2B49%2089%2032399-200> > http:www.irt.de <http://www.irt.de> | Email:tai@irt.de <mailto:tai@irt.de> > ------------------------------------------------ > > registration court& managing director: > Munich Commercial, RegNo. B 5191 > Dr. Klaus Illgner-Fehns > ------------------------------------------------ > > > ---------------------------- > > http://www.bbc.co.uk <http://www.bbc.co.uk> > This e-mail (and any attachments) is confidential and may contain > personal views which are not the views of the BBC unless specifically > stated. > If you have received it in error, please delete it from your system. > Do not use, copy or disclose the information in any way nor act in > reliance on it and notify the sender immediately. > Please note that the BBC monitors e-mails sent or received. > Further communication will signify your consent to this. > > --------------------- > > > This message may contain confidential and/or privileged information. > If you are not the intended recipient you must not use, copy, disclose > or take any action based on this message or any information herein. If > you have received this message in error, please advise the sender > immediately by reply e-mail and delete this message. Thank you for > your cooperation. Screen Subtitling Systems Ltd. Registered in England > No. 2596832. Registered Office: The Old Rectory, Claydon Church Lane, > Claydon, Ipswich, Suffolk, IP6 0EQ > -- ------------------------------------------------ Andreas Tai Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR Floriansmuehlstrasse 60, D-80939 Munich, Germany Phone: +49 89 32399-389 | Fax: +49 89 32399-200 http: www.irt.de | Email: tai@irt.de ------------------------------------------------ registration court& managing director: Munich Commercial, RegNo. B 5191 Dr. Klaus Illgner-Fehns ------------------------------------------------
Received on Wednesday, 17 July 2013 15:00:53 UTC