See also: IRC log
ericc: could have an extra video track as part of the main video resource
cyril: mp4 has this already
ericc: problem is that you only
have thumbnails for the currently buffered portion of
video
... people want to see thumbnails for the whole length
regarldess of what's buffered
<nigel> scribeNick: hober
[scribe missed a bit]
ericc: another way to do it would
be to have a separate video file for the thumbnails
... we need a way to associate that with a <video>
could define a new <track kind> value
scribe: one advantage is that it's self-contained, with images and timestamps
FrankOlivier: with compression etc., small file, loads quickly
ericc: could use an image sprite
nigel: video files don't
necessarily have timestamps, may just have frame numbers or
offset info
... Where in the system architecture should the mapping be done
between main video times and thumbnail times: for example what
if you want 1 thumbnail per minite of the main video
FrankOlivier: you'd make the thumbnail video have a lower framerate
ericc: have it be the same duration as the main video
cyril: jwplayer uses a vtt file containing geometry fragids to a single image sprite
<cyril> https://support.jwplayer.com/customer/portal/articles/1407439-adding-preview-thumbnails
zcorpan: use cases?
ericc: builtin controls and custom controls
cyril: is this a video track in the main video or a separate file
ericc: you want both
cyril: if the video contains captions in the video file, does edge expose those text tracks to js?
FrankOlivier: we don't
ericc: webkit does
... sites that implement custom controls should be able to use
this
zcorpan: doesn't make sense as a
track element
... prefer thumbs=""
hober: what about multiple sizes, need microsyntax
FrankOlivier: need multiple formats too, prefers track elements
cyril: we want both, for live you want the thumbs in-band
ericc: we don't have to block the load event like we do for enabled text tracks
nigel: thumbnail viewer is a <video> itself
FrankOlivier: this is MediaController
zcorpan: no, because you might
show a range of thumbs at once
... this is not semanticly a track, we should not use
<track>
cyril: similar to <track kind=chapter>
FrankOlivier: [something about data cues]
[chat about native controls v. custom controls; novel ui possible]
ericc: maybe a cue type, like
data cue
... then you get an event when it's time to display some
thumbnail
... not sure that's useful
zcorpan: events don't help
ericc: want a method to get the thumb for a time
FrankOlivier: or to get all of them
zcorpan: and their timings
ericc: and you get blob urls for lazy resolution
nigel: [rounding concern]
ericc: it's simple, it's frame in
thumbnail video at same time
... up to author to use same time scale
FrankOlivier: media fragments api has time offset and id
[frank and cyril talk about media frag id being frame id]
ericc: do we need the "get the thumb for time x" api
hober: yes
eric: problem in [something] we shouldn't repeat
ericc: for live content, don't want to hang onto old thumbs that you can't seek back to
zcorpan: UA should be able to purge thumbs for unseekable ranges
ericc: yes
... we should do the same thing for vtt
[more vtt and live streams discussion]
ericc: does it make sense to support both kinds, jwplayer-style and a video file
FrankOlivier: video file only
zcorpan, hober: agreed
[scribe missed something MarkVickers said]
cyril: [concern about compression and performance]
ericc: not a problem in practice, can use hardare decoder
nigel: what about devices with a signle hardward decoder
ericc: software decoder fallback is fine
nigel: animated why not generalise to any format that allows a particular single image at a time to be referenced?
ericc: anything the platform supports as a video
MarkVickers: alternate video track with all iframes
ericc: like mp4, need way to
identify purpose of in-band track
... makes sense for live content
MarkVickers: what about on demand?
ericc: can only display thumbs
for currently buffered range
... this is another reason for <track type>
zcorpan: this complicates media loading
hober: only if you support them
zcorpan: but you need to expose them to js
nigel: json file with links to images
FrankOlivier: you could use data
cue for that
... on cell network, loading lots of images separately is
bad
zcorpan: how do you envision
multiple sizes working?
... wouldn't work with <track kind>, need something else
as well
hober: like sizes=""
zcorpan: or srcset=""
ericc: we only need to expose something if it's important for script to be able to pick whih thumb track
hober: what about custom controls
FrankOlivier: reinventing media queries?
zcorpan ericc: no
[something about adaptive streaming and evaluation of media queries]
cyril: what's the relationship between thumbnails and posters
ericc: poster is dimensions of
main video, dimensions of thumb video is different
(smaller)
... coming up with api for script to be able to specify
resolution
need to expose metadata about each video track in the thumbnail video, including resolution and which one is selected
nigel: maybe storyboard not the same as scrubbing thumbnails
cyril: might want to check sourcing in-band media ... document
<cyril> https://dev.w3.org/html5/html-sourcing-inband-tracks/
hober: action items?
<scribe> ACTION: zcorpan to file bug on HTML [recorded in http://www.w3.org/2016/09/21-thumb-minutes.html#action01]
<zcorpan> https://github.com/whatwg/html/issues/1805 Should allow purging of unseekable inband cues
This is scribe.perl Revision: 1.144 of Date: 2015/11/17 08:39:34 Check for newer version at http://dev.w3.org/cvsweb/~checkout~/2002/scribe/ Guessing input format: RRSAgent_Text_Format (score 1.00) Succeeded: s/quicly/quickly/ Succeeded: s/??/nigel/ Succeeded: s/what if/Where in the system architecture should the mapping be done between main video times and thumbnail times: for example what if/ Succeeded: s/odn't/don't/ Succeeded: s/gif?/ why not generalise to any format that allows a particular single image at a time to be referenced?/ Found ScribeNick: hober Inferring Scribes: hober WARNING: No "Topic:" lines found. Present: cyril hober zcorpan ericc MarkVickers FrankOlivier nigel Got date from IRC log name: 21 Sep 2016 Guessing minutes URL: http://www.w3.org/2016/09/21-thumb-minutes.html People with action items: zcorpan WARNING: No "Topic: ..." lines found! Resulting HTML may have an empty (invalid) <ol>...</ol>. Explanation: "Topic: ..." lines are used to indicate the start of new discussion topics or agenda items, such as: <dbooth> Topic: Review of Amy's report[End of scribe.perl diagnostic output]