Bug 190669 - Apply WebVTT embedded Styles using Voice Span
Summary: Apply WebVTT embedded Styles using Voice Span
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Media (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2018-10-17 10:34 PDT by Rafik Mikhael
Modified: 2023-09-08 15:40 PDT (History)
6 users (show)

See Also:

Attachments
Source SubStation Alpha subtitles (1.44 KB, text/plain)
2018-10-17 10:34 PDT, Rafik Mikhael 		no flags Details
Converted WebVTT segment to be rendered. (1.60 KB, text/plain)
2018-10-17 10:35 PDT, Rafik Mikhael 		no flags Details
how libASS renders (362.44 KB, image/jpeg)
2018-10-17 10:35 PDT, Rafik Mikhael 		no flags Details
How browser renders. (363.85 KB, image/jpeg)
2018-10-17 10:36 PDT, Rafik Mikhael 		no flags Details
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Rafik Mikhael 2018-10-17 10:34:46 PDT 
Created attachment 352581 [details]
Source SubStation Alpha subtitles

This might be a duplicate of Bug ID #190369. But could provide a good example for your testing/dev work.

At Ellation we implemented live ASS to WebVTT conversion on Kaltura's nginx-vod-module. When we open our Stream URL on the browser, and enable subtitles/captions we don't get the expected styled fonts.

We are using styles with the following tags:
color, font-family, font-size, text-shadow, text-decoration.

We are applying some of these style tags using a voice span, and one of them using class specifier.

Neither of these is getting rendered correctly. Both fallback to White on Black background with fixed font-size from a fixed font-family.

I am running on macOS Sierra.

Attaching source ASS, and target WebVTT files, along with how libASS renders the text, vs how it is rendered on the browser.
Comment 1 Rafik Mikhael 2018-10-17 10:35:39 PDT 
Created attachment 352582 [details]
Converted WebVTT segment to be rendered.
Comment 2 Rafik Mikhael 2018-10-17 10:35:57 PDT 
Created attachment 352583 [details]
how libASS renders
Comment 3 Rafik Mikhael 2018-10-17 10:36:17 PDT 
Created attachment 352584 [details]
How browser renders.
Comment 4 Radar WebKit Bug Importer 2018-10-22 10:49:04 PDT 
<rdar://problem/45458144>