Bug Description
1. Summary
Some webvtt files are not displayed when using ShakaPlayer’s text track rendering.
Bug Severity
Select one that applies
- Impacts operation of app
- Blocks current development
- Improvement suggestion
- Issue with documentation (If selected, please share the doc link and describe the issue)
- Other
2. Steps to Reproduce
- Load the problematic VTT into ShakaPlayer with addTextTrackAsync
- Subtitles don’t display at all
3. Observed Behavior
Explain what actually happened, noting any discrepancies or malfunctions.
Subtitles don't display at all
4. Expected Behavior
Describe what you expected the SDK to do under normal operation.
Subtitles are displayed correctly
4.a Possible Root Cause & Temporary Workaround
Fill out anything you have tried. If you don’t know, N/A is acceptable
N/A
5. Logs or crash report
6. Environment
Please fill out the fields related to your bug below:
-
SDK Version: 0.20.3494
-
App State:
[Foreground] -
OS Information
Please ssh into the device viakepler exec vda shelland copy the output fromcat /etc/os-releaseinto the answer section below. Note, if you don’t have a simulator running or device attachedkepler exec vda shellwill respond withvda: no devices/emulators foundNAME="OS" OE_VERSION="4.0.0" OS_MAJOR_VERSION="1" OS_MINOR_VERSION="1" RELEASE_ID="2" OS_VERSION="1.1" BRANCH_CODE="VegaMainlineTvIntegration" BUILD_DESC="OS 1.1 (VegaMainlineTvIntegration/10188080)" BUILD_FINGERPRINT="1.0.18808.0(9a1d8dfa7da5d600)/10188080N:user/dev-keys" BUILD_VARIANT="user" BUILD_TAGS="dev-keys" BUILD_DATE="Fri Aug 22 16:02:33 UTC 2025" BUILD_TIMESTAMP="1755878553" VERSION_NUMBER="202028808030"
7. Example Code Snippet / Screenshots / Screengrabs
Include any relevant code or component setup in React Native that can help reproduce the bug.
this.player.addTextTrackAsync(uri, language, kind, mimeType, codec, label, forced)
Playback Issues
If this is a playback issue, please provide your VPKG and/or content URL, any pre-conditions (like geo-location) [Share privately with your Amazon contact] , and let us know if it’s x86 or arm7.
<!-- Describe your playback issue if applicable -->
Please share the following details in addition:_
- Player SDK:
[Shaka] - Player SDK Version:
[4.6.18]- Audio Codecs:
[AAC] - Video Codecs:
[h.265, mp4] - Manifest Types:
[dash]
- Audio Codecs:
Q: Would you like to be contacted to share your latest VPKG compiled with latest SDK:
[Y/N] [Share privately with your Amazon contact]
Q: VPN or Login needed to verify functionality in VPKG?
[Y/N] [Share privately with your Amazon contact]
Q: If applicable, please provide your media/content url
If this is created dynamically, tokenized, etc please provide a way for us to access it
N/A
Q: Are there any special headers required to reproduce the issue you are facing?
N/A
Additionally please provide the following if possible
Provide Screenshots / Screengrabs / Logs. Please include as much information as you can that will help debug.
<!-- Answer here if applicable -->
Additional Context
Any Additional Context you would like to provide?
Add any other relevant information, such as recent updates to the SDK, dependencies, or device OS that may affect the bug.
WebVTT witt problems
WEBVTT
00:00:00.000 --> 00:01:00.000 line:100%,end position:50%,center
Line1 Text
<i>Line2</i>
WEBVTT
00:00:00.000 --> 00:01:00.000 line:100%,end position:50%,center
Line1 Text
<b>Line2 Text</b>
WEBVTT
00:00:00.000 --> 00:01:00.000 line:100%,end position:50%,center
Line1 Text
<u>Line2 Text</u>
WEBVTT
00:00:00.000 --> 00:01:00.000 line:100%,end position:50%,center
Line1 Text
<v>Line2 Text</v>
WebVTT without problems
(but style is not applied)
WEBVTT
00:00:00.000 --> 00:01:00.000 line:100%,end position:50%,center
<i>Line1</i>