Safari 10.1 throws Error: The provided value is non-finite

[ChristiaanScheermeijer]

When using vtt.js in Safari it throws Error: The provided value is non-finite on this part cue.line = settings.get("line", "auto");.

I think this is an issue in the Safari VTTCue implementation, but I hope to find a workaround in this polyfill.

Below the stacktrace:

consumeCueSettings@http://localhost:9000/bower_components/vtt.js/lib/vtt.js:269:10
parseCue@http://localhost:9000/bower_components/vtt.js/lib/vtt.js:303:23
parse@http://localhost:9000/bower_components/vtt.js/lib/vtt.js:1268:23

• macOS Sierra 10.12.4
• Safari Version 10.1 (12603.1.30.0.34)

[johnBartos]

Here's what we do in jwplayer:

var line = settings.get('line', 'auto');
if (line === 'auto' && defaults.line === -1) {
    // set numeric line number for Safari
    line = -1;
}
cue.line = line;

[aligon]

Here's how we worked around it:

const oldVTTCue = global.VTTCue;

try {
    global.VTTCue = VTTCue;

    parser.parse(vtt);
    parser.flush();
} finally {
    global.VTTCue = oldVTTCue;
}

The VTTCue in scope is the one from vtt.js

[jsg2021]

The spec clearly allows for 'auto' :|
https://w3c.github.io/webvtt/#webvtt-cue-line

Apple's native VTTCue is not spec compliant.

[ChristiaanScheermeijer]

Agreed, but why not solving it in the polyfill?

[ChristiaanScheermeijer]

Thanks, cue.position also throws this error.

[jsg2021]

I added position to my PR

[jsg2021]

Apparently the travis build failed with that change... :/ position wasn't 'auto'?

[jsg2021]

Ugh... apparently that breaks the tests. cue.position is auto by default (in chrome & ff...in safari its 50) and I'm just using the default if set... and falling back to what was there... :/

[ChristiaanScheermeijer]

Im using cue.line !== "auto" ? cue.line : "auto" for line and position which seem to work. Not sure if they pass the test though.

[jsg2021]

This is not really resolved yet...

[jsg2021]

my PR should fix it