- From: John Birch <john.birch@screen.subtitling.com>
- Date: Fri, 19 Sep 2008 15:06:20 +0100
- To: "Timed Text Working Group WG" <public-tt@w3.org>
Hi Geoff, You raise an interesting point. I agree, in all captioning systems it is possible to locate captions as appropriate to avoid other on-screen activity. In a live presentation, in a TV captioning scenario, the location of the captions may often be controlled as you describe by the captioner / subtitler. In some cases captions are automatically relocated under control of automation or other equipment (for example - logo insertion equipment). Note: In the US systems [608 and 708], captions may be relocated **by the viewer** Incidentally - this is unique to 608/708 captioning methods, all other TV captioning standards do not allow the viewer to control caption presentation sytle (including position), only caption visibility. Yet, for the DFXP scenario I am undecided if the problem you describe does actually exist. As mentioned above, for a pre-recorded media asset the captions can be correctly located because the captioner has a priori knowledge. However, for a 'live' asset, it is not possible to use the standard DFXP mechanism (a single DFXP file) for the captioning - since parsing of that file requires a complete file to be present (in theory if not in practice :-). Hence the streamed DFXP that was introduced into DFXP. Would it not be possible to create locations for dynamic flowed content that exist only within each of the units of DFXP that are streamed? I confess to not having that aspect of the CR in my head... So apologies if this is invalid. But my understanding was that the streamed version of DFXP was intended to cater for this type of issue... That is a lack of a priori knowledge about what needs to be transmitted... BTW - my main concerns about dynamic flow are that it won't actually work (as I think it needs to) under the CR proposal :-) Note: - I do not equate 'live captioning' with dynamic flow... I see dynamic flow as equally valid for a downloaded media asset with captions (in which case dynamic flow is a means to avoid timing and flowing all the captions explicitly). Yours sincerely, John Birch John Birch | Screen Subtitling Systems Ltd | Strategic Partnerships Manager Main Line : +44 (0)1473 831700 | Ext : 270 | Office : Mobile: +44 (0)7919 558380 | Fax: +44 (0)1473 830078 john.birch@screen.subtitling.com | www.screen.subtitling.com The Old Rectory, Claydon Curch Lane, Claydon,Ipswich,IP6 0EQ,United Kingdom See us at HD World, New York, October 15th - 16th, Stand 1110 Before Printing, think about the environment -----Original Message----- From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On Behalf Of Timed Text Working Group Issue Tracker Sent: 19 September 2008 14:43 To: public-tt@w3.org Subject: ISSUE-1 (dynamicFlow): dynamicFlow in DFXP cannot emulate an important feature of EIA-608 captions ISSUE-1 (dynamicFlow): dynamicFlow in DFXP cannot emulate an important feature of EIA-608 captions http://www.w3.org/AudioVideo/TT/tracker/issues/1 Raised by: Geoff Freed On product: One of my concerns about the current dynamicFlow in DFXP is that it cannot emulate an important feature of EIA-608 captions, which is the ability to create and change regions on the fly. Currently, dynamicFlow can feed text into pre-created regions in pre-specified locations. In a real-time-captioning situaton, region locations may not be known ahead of time, and during a broadcast blocks of caption text sometimes have to be moved from, say, the lower-third of the picture to the upper-third to avoid covering important graphics, or sometimes they are just moved up (or down) one or two rows. As far as I know, DFXP does not allow to on-the-fly creation of new regions, does it? If not, then the current dynamicFlow isn't really suited for live captioning or subtitling, and this is something that I'd like to improve, it if is possible within the bounds of the charter. 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
Received on Friday, 19 September 2008 14:07:02 UTC