Re: Decisions related to "line" and "position" cue settings

I've used mp4box before, am not sure it the result is compatible with those
players. I'll have to give it a try.

Best Regards,
Silvia.
On 18 Oct 2014 09:10, "Courtney Kennedy" <ckennedy@apple.com> wrote:

> Hi Philip,
>
> That’s correct, it handles vtt in ISO files or in HTTP Live Streaming.  I
> do not know of any free or inexpensive tools that are publicly available
> that do create ISO files with VTT in them. MacCaptions has this
> functionality.
> ______________________________
> Courtney Kennedy
> Engineering Manager, Media Sharing
> mobile: 408-771-8615
>
>
>
> > On Oct 17, 2014, at 3:04 PM, Philip Jägenstedt <philipj@opera.com>
> wrote:
> >
> > Hi Courtney,
> >
> > I've upgraded to Yosemite, but am unable load an external .vtt file in
> > QuickTime Player. Does it only support in-band WebVTT and if so, are
> > there any tools that can mux a video file with a .vtt file for
> > testing?
> >
> > Philip
> >
> > On Fri, Oct 17, 2014 at 7:28 PM, Courtney Kennedy <ckennedy@apple.com>
> wrote:
> >> Hi Again Silvia,
> >>
> >> Now that OS X Yosemite is available, I can also let you know that it has
> >> full support for WebVTT in QuickTime Player X and in iTunes Player, or
> in
> >> any 3rd party apps built using Apple's AVFoundation framework for video
> >> playback.  Both Yosemite and iOS 8 have the same level of support for
> >> WebVTT.
> >>
> >> Best Regards,
> >> Courtney
> >> ______________________________
> >> Courtney Kennedy
> >> Engineering Manager, Media Sharing
> >>
> >>
> >>
> >>
> >> On Oct 12, 2014, at 1:44 PM, Courtney Kennedy <ckennedy@apple.com>
> wrote:
> >>
> >> Hi Silvia,
> >>
> >>
> >> On Oct 11, 2014, at 11:29 PM, Silvia Pfeiffer <
> silviapfeiffer1@gmail.com>
> >> wrote:
> >>
> >> Hi Courtney,
> >>
> >> Thanks, that's great information. When you say that it supports the
> >> full content of the WebVTT spec, does that mean you also support
> >> regions?
> >>
> >>
> >> Yes, we implemented support for regions.
> >>
> >> How can I test the features? Is the Video Player App
> >> available on MacBooks? (I couldn't find it).
> >>
> >>
> >> Its available on iOS8.
> >>
> >> Is there a set of test
> >> files that you support so we can make sure to be compatible with your
> >> implementation in the spec?
> >>
> >>
> >> We are working on putting together a set of test files, but don’t have
> them
> >> ready yet.
> >>
> >>
> >> Thanks,
> >> Silvia.
> >>
> >>
> >> On Thu, Oct 9, 2014 at 6:51 AM, Courtney Kennedy <ckennedy@apple.com>
> wrote:
> >>
> >> Hi Philip,
> >>
> >> Apple’s Video Player App and any third party video players that build
> upon
> >> Apple's AVFoundation APIs support the full current version of the WebVTT
> >> spec in iOS 8.  Webkit does not yet.
> >>
> >> Courtney
> >>
> >> On Oct 8, 2014, at 12:32 PM, Philip Jägenstedt <philipj@opera.com>
> wrote:
> >>
> >> Hi Courtney,
> >>
> >> That would indeed qualify as strong interest.
> >>
> >> I can't find any trace of this implementation in WebKit:
> >>
> https://trac.webkit.org/browser/trunk/Source/WebCore/html/track/VTTCue.idl
> >> (no lineAlign/positionAlign)
> >>
> https://trac.webkit.org/browser/trunk/Source/WebCore/html/track/VTTCue.cpp
> >> (nothing relevant in setCueSettings)
> >>
> >> Searching the Web for "WebVTT iOS8" also doesn't find anything useful.
> >>
> >> I guess it's still in Apple's non-public repo and not widely known
> >> yet? Since I don't have an iOS device to test with, can you provide
> >> some details on which bits have been implemented?
> >>
> >> Thanks!
> >>
> >> Philip
> >>
> >> On Wed, Oct 8, 2014 at 7:56 PM, Courtney Kennedy <ckennedy@apple.com>
> wrote:
> >>
> >> Hi Philip,
> >>
> >> As I stated in my response to Silvia on September 8th, I am strongly in
> >> favor of having the current version of the spec become V1, with these
> >> features in place.    Apple implemented support for these features in
> iOS8,
> >> so there is an existing implementation available now.   I think that
> >> qualifies as strong implementor interest.
> >>
> >> Best Regards,
> >> Courtney Kennedy
> >>
> >> On Oct 8, 2014, at 5:49 AM, Philip Jägenstedt <philipj@opera.com>
> wrote:
> >>
> >> On Mon, Sep 8, 2014 at 6:39 AM, Silvia Pfeiffer
> >> <silviapfeiffer1@gmail.com> wrote:
> >>
> >> Hi everyone,
> >>
> >> As you may have noticed, Philip and I had some intensive discussions
> >> about text positioning in general and the "line" and "position" cue
> >> settings in particular over the last 6 months.
> >>
> >> The way I've come to look at text positioning is that the lines in a
> >> cue together form a cue box and get positioned together. The width and
> >> height of the cue box is defined by the smallest box that all line
> >> boxes would fit into (the bounding box) with a width restriction width
> >> given by the "size" setting. Within that cue box, text alignment is
> >> controlled via the "align" setting.
> >>
> >> When we look at the "line" setting (i.e. vertical positioning), in the
> >> past, the "line" setting positioned the first line in a cue (for
> >> snap-to-lines) and the percentage-point of the cue box for a
> >> percentage-point "line" setting. This meant that it was basically
> >> impossible to e.g. position a cue box such that the top of the cue box
> >> was positioned at the center point of the viewport.
> >>
> >> Therefore, we introduced what I called the "line alignment" setting.
> >> It allowed specifying whether the top, the center, or the bottom of
> >> the cue box was aligned to the "line" setting position.
> >>
> >> For example: line:10%,top would align the top of the cue box at the
> >> 10% mark of the video height.
> >>
> >> Similarly, we introduced what I called the "position alignment"
> >> setting, which does the same for the "position" setting: it allows
> >> specifying whether the left, the center or the right of the cue box
> >> was aligned to the "position" setting. This would, e.g. allow left
> >> aligned text in its cue box to be centered in the horizontal middle of
> >> the video.
> >>
> >> Or another example: position:20%,right would right align the cue box
> >> at the 20% mark of the video width (it would still at most be 80%
> >> wide, or less depending on the "size" setting).
> >>
> >>
> >> Now, Philip has pointed out that these specs are not backwards
> >> compatible. Adding a second, comma-separated value to the "position"
> >> and "line" settings basically makes existing implementations of these
> >> fail. E.g. line:10%,middle will not fall back to line:10%, but will
> >> rather fail parsing and result in no explicit "line" setting,
> >> reverting back to the default -1 line.
> >>
> >> We therefore have a choice:
> >>
> >> 1. We can live with this lack of backwards compatibility. If somebody
> >> decides that they need to specify the alignment for the cue box in
> >> relation to the "line" and "position" settings, they will want a full
> >> implementation of that feature anyway.
> >>
> >> 2. We can move these alignments to extra cue settings. Thus, we would
> >> introduce "lineAlign" and "positionAlign" as two new cue settings that
> >> apply to the cue box alignment. This will make sure that we remain
> >> backwards compatible.
> >>
> >>
> >> I'm happy to go with either of these two options, so am curious to
> >> hear what people think.
> >>
> >> Incidentally, there is a second question here: should these be
> >> features of v1 (and thus go down the path towards the REC spec), or is
> >> it sufficient to move these off to v2?
> >>
> >> Opinions?
> >>
> >>
> >> My preference is separate settings in the syntax, which would map
> >> better to the IDL interface. Chaning the syntax will make it trickier
> >> to write markup that works OK-ish in both old and new parsers. For the
> >> same reason, it would also be good if the new settings moves the cues
> >> around as little as possible, so that even if the alignment isn't
> >> correct they're still on the same place on screen.
> >>
> >> Of course, I must admit that part of the reason is that I'm still on
> >> the fence about whether this is worth implementing at all. I think
> >> this should be a v2 feature or wontfix, unless we have some strong
> >> implementor interest elsewhere.
> >>
> >> Philip
> >>
> >>
> >>
> >>
> >>
> >> ____________
> >> Courtney Kennedy 408.974.3386, mobile: 408.771.8615
> >> Engineering Manager, Media Sharing
> >> Apple, Inc.
> >>
> >>
>
>