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[sdw] WebVMT: Missing video file reference

From: Rob Smith via GitHub <sysbot+gh@w3.org>
Date: Fri, 18 May 2018 12:03:51 +0000
To: public-sdwig@w3.org
Message-ID: <issues.opened-324383955-1526645030-sysbot+gh@w3.org>
rjksmith has just created a new issue for https://github.com/w3c/sdw:

== WebVMT: Missing video file reference ==
In the current design, the video and map-track files are only associated in the HTML of the web page. I believe is an error, which I noticed during my recent implementation of the video capture tech demo.

WebVMT is a file format which should be agnostic of any webpages. I've found three use cases so far which highlight the issue:

1. A capture app which creates video and map-track files knows how they are associated. The design requires that the video file is unchanged by WebVMT, so this information must be stored in the VMT file. No HTML is involved.

1. A web page is designed to display user-loaded files, and expects to receive a video file and a VMT file. The HTML of the page contains no file association information, but must be able to correctly police the files loaded. This example becomes more obvious if the web page is imagined to accept two pairs of files into two displays, as the loading process can present the files in any order, e.g. video1.mp4, video2.vmt, video2.mp4 and video1.vmt, and the page must make the correct associations.

1. An archive of video and VMT files is shared online for display using the webpage above, so there is no file association in the HTML. A VMT-aware web crawler accessing the site needs to know the file associations to construct a valid geospatial-temporal index of each video file from its VMT details.

I propose to add a simple VIDEO block containing a URI value, as demonstrated below.

 * Example: video1.mp4 and video1.vmt in the same directory.
```
VIDEO {
    uri: video1.mp4;
}
```
* Example: video2.webm and video2.vmt in parallel directories.
```
VIDEO {
    uri: ../movies/video2.webm;
}
```
* Example: yourvideo.ogg and myvideo.vmt on different servers.
```
VIDEO {
    uri: http://yourdomain.com/yourpath/yourvideo.ogg;
}
```

Please view or discuss this issue at https://github.com/w3c/sdw/issues/1035 using your GitHub account
Received on Friday, 18 May 2018 12:05:03 UTC

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