- From: Glenn Adams <glenn@skynav.com>
- Date: Wed, 7 Dec 2016 11:42:41 -0700
- To: sylvain.kervadec@orange.com
- Cc: Nigel Megitt <nigel.megitt@bbc.co.uk>, "public-tt@w3.org" <public-tt@w3.org>
- Message-ID: <CACQ=j+eTgEqcCTTbhYyVCwJrhRo8sPPn2jmoEe00hMN5enMt0g@mail.gmail.com>
To be clear, I should add that, if no timing appears on region, then regions are always temporally active in TTML1; therefore, if showBackground is always, then you are correct that a region would be displayed regardless of whether content is selected into the region. Note, however, that if a region has a transparent background, then there would be no visible marks. You will need to specify whenVisible on showBackground to avoid this situation. In TTML2, one could simply specify <initial tts:showBackground="whenActive"/> to change the initial value, but you don't have this option in TTML1/IMSC1. On Wed, Dec 7, 2016 at 11:05 AM, Glenn Adams <glenn@skynav.com> wrote: > > > On Wed, Dec 7, 2016 at 7:24 AM, <sylvain.kervadec@orange.com> wrote: > >> Dear Nigel, >> >> >> >> Thanks for your feedback. >> >> This errata however clarifies the ‘whenActive’ case, but my >> misunderstanding concerns the ‘always’ case. >> >> >> >> It may come from my wrong interpretation of what is a “Temporally Active >> Region”. >> >> In my example, only the content elements carry timing attributes (‘begin’ >> and ‘end’). My understanding is that a region is a temporally active region >> when a temporally active content element is associated with it. Temporally >> inactive regions are thus not displayed, whatever the value of >> tts:showBackground. >> > > Regions are also timed and can take begin/end/dur. See also [1] and [2], > particularly: > > > To the extent that time semantics apply to the content of the layout element, > the implied time interval of this element is defined to be coterminous with > the *Root Temporal Extent*. > [1] https://www.w3.org/TR/ttaf1-dfxp/#layout-vocabulary-region > [2] https://www.w3.org/TR/ttaf1-dfxp/#layout-vocabulary-layout > > > >> But for example, if a region has to be considered as temporally active >> during the entire life of the document, then the tts:showBackground value >> has to be evaluated and rendered, even when no content element associated >> with this region is temporally active. >> >> >> >> IMSC1 prohibits overlapping presented regions. My example would thus be >> allowed or prohibited depending on the answer (Actually, it breaks IMSC1 >> compatibility on other features). >> >> >> >> Best regards, >> >> Sylvain. >> >> >> >> >> >> *De :* Nigel Megitt [mailto:nigel.megitt@bbc.co.uk] >> *Envoyé :* mercredi 7 décembre 2016 12:27 >> *À :* KERVADEC Sylvain IMT/OLPS; public-tt@w3.org >> *Objet :* Re: TTML / tts:showBackground='always' >> >> >> >> Dear Sylvain, >> >> >> >> Please could you read the errata to TTML1 at https://www.w3.org/2013/09/ >> ttml1-errata.html#errata-8.2.17-1 and see if it answers your question? >> >> >> >> For ease of reference, that section is: >> >> >> >> [[ >> >> Correction in TTML1 Section 8.2.17 - tts:showBackground attribute >> <http://www.w3.org/TR/2013/REC-ttml1-20130924/#style-attribute-showBackground> (published >> 2014-07-31) >> >> *Description*: >> >> Clarify meaning of whenActive. >> >> *Resolution*: >> >> Add the following paragraph immediately prior to the paragraph starting >> with "If a computed value of the property ...": >> >> A region satisfies the whenActive case if (1) it is a *Temporally Active >> Region* and (2) content is selected into the region, where that content >> is also *Temporally Active*. >> ------------------------------ >> >> ]] >> >> >> >> Kind regards, >> >> >> >> Nigel >> >> >> >> >> >> *From: *"sylvain.kervadec@orange.com" <sylvain.kervadec@orange.com> >> *Date: *Wednesday, 7 December 2016 at 09:41 >> *To: *"public-tt@w3.org" <public-tt@w3.org> >> *Subject: *TTML / tts:showBackground='always' >> *Resent-From: *<public-tt@w3.org> >> *Resent-Date: *Wednesday, 7 December 2016 at 09:43 >> >> >> >> Dear tt experts, >> >> >> >> I am looking for some clarifications on the expected behavior >> of the tts:showBackground parameter defined on a temporally inactive region. >> >> To be more specific, I would like to know if the background of a >> temporally inactive region with a tts:showBackground equal to ‘always’ >> shall be displayed or not. >> >> The topic has already been discussed (https://www.w3.org/AudioVideo >> /TT/tracker/issues/314, and 313, 330), but I still don’t know what is >> the correct answer. >> >> >> >> I am using TTML2 as a reference, as it introduces some missing >> definitions on active regions: >> >> The tts:showBackground definition says that “the background color of a >> region is always rendered when performing presentation processing on a >> visual medium”, when its value is equal to ‘always’. >> >> However, the text also says “For the purpose of determining the >> semantics of presentation processing, a region that is temporally inactive >> must not produce any visible marks when presented on a visual medium.” >> >> Reading IMSC1, “A presented region is a temporally active region that >> satisfies the following conditions:..” seems to indicate that an inactive >> region shall not be presented. >> >> >> >> My understanding is thus that an inactive region shall not be displayed, >> whatever the value of tts:showBackground, but I would appreciate your >> guidance on the topic. >> >> >> >> Here is an example: >> >> >> >> *<?xml version="1.0" encoding="UTF-8"?>* >> >> *<tt xml:lang="fre" xmlns="http://www.w3.org/2006/10/ttaf1 >> <http://www.w3.org/2006/10/ttaf1>" >> xmlns:ttp="http://www.w3.org/2006/10/ttaf1#parameter >> <http://www.w3.org/2006/10/ttaf1#parameter>" >> xmlns:tts="http://www.w3.org/2006/10/ttaf1#styling >> <http://www.w3.org/2006/10/ttaf1#styling>" ttp:cellResolution="50 30">* >> >> * <head>* >> >> * <styling>* >> >> * <style xml:id="ts0" tts:fontFamily="monospaceSansSerif" >> tts:lineHeight="1c" tts:textDecoration="none" tts:fontWeight="normal" >> tts:fontStyle="normal" tts:fontSize="1c 1c" tts:color="#FFFFFFFF" >> tts:backgroundColor="#00000064" tts:textOutline="#000000FF 0.1c 0c"/>* >> >> * <style xml:id="ts1" tts:lineHeight="2c" >> tts:textDecoration="none" tts:fontWeight="normal" tts:fontStyle="normal" >> tts:fontSize="1c 2c" tts:color="#FFFFFFFF" tts:backgroundColor="#00000064" >> tts:textOutline="#000000FF 0.1c 0c"/>* >> >> * <style xml:id="ps0" tts:textAlign="center"/>* >> >> * </styling>* >> >> * <layout>* >> >> * <region xml:id="r0" tts:origin="10% 73%" tts:extent="80% 17%" >> tts:displayAlign="before"/>* >> >> * <region xml:id="r1" tts:origin="10% 66%" tts:extent="80% 24%" >> tts:displayAlign="before"/>* >> >> * </layout>* >> >> * </head>* >> >> * <body>* >> >> * <div style="ts0">* >> >> * <p region="r0" begin="00:00:00.280" end="00:00:01.640" >> style="ps0">* >> >> * <span style="ts1" xml:space="preserve">extirpé ?</span>* >> >> * </p>* >> >> * <p region="r0" begin="00:00:02.720" end="00:00:04.840" >> style="ps0">* >> >> *<span style="ts1" xml:space="preserve">Je dois dire >> que...</span>* >> >> *</p>* >> >> * <p region="r0" begin="00:00:07.880" end="00:00:09.960" >> style="ps0">* >> >> *<span style="ts1" xml:space="preserve">mes yeux sont verts, >> en fait.</span>* >> >> *</p>* >> >> * <p region="r1" begin="00:00:11.360" end="00:00:11.360" >> style="ps0">* >> >> *<span style="ts1" xml:space="preserve">Je ne qualifierais >> pas</span>* >> >> *</p>* >> >> * <p region="r1" begin="00:00:11.360" end="00:00:13.280" >> style="ps0">* >> >> *<span style="ts1" xml:space="preserve">Je ne qualifierais >> pas</span>* >> >> *<br/>* >> >> * <span style="ts1" xml:space="preserve">notre >> réticence</span>* >> >> * </p>* >> >> * </div>* >> >> * </body>* >> >> *</tt>* >> >> >> >> The tts:showBackground defaults to ‘always’. >> >> Two overlapping regions are defined (for single-line and two-lines >> subtitles), only one being active at any time. >> >> If we have to display the background for inactive regions, it does not >> look good, as we have two semi-transparent regions on top of each other. >> >> Adding tts:showBackground=’whenActive’ would solve our problem, but our >> contents have been generated without any tts:showBackground value so far. >> >> >> >> >> >> Thanks in advance for your help. >> >> Best regards, >> >> Sylvain >> >> >> >> >> >> >> >> _________________________________________________________________________________________________________________________ >> >> >> >> Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc >> >> pas etre diffuses, exploites ou copies sans autorisation. 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Les messages electroniques etant susceptibles d'alteration, >> Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. >> >> This message and its attachments may contain confidential or privileged information that may be protected by law; >> they should not be distributed, used or copied without authorisation. >> If you have received this email in error, please notify the sender and delete this message and its attachments. >> As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified. >> Thank you. >> >> >
Received on Wednesday, 7 December 2016 18:43:38 UTC