[DASH Playback] Frames from previous ad period overlap current period

:warning: Before you continue


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NOTE: PLEASE ONLY REPORT A SINGLE BUG USING THIS TEMPLATE.
If you’re experiencing multiple issues, please file a separate report for each.


:backhand_index_pointing_right: Bug Description


1. Summary

Using Shaka for DASH multi-period VOD playback with DAI ad periods, video frames are appended out of sequence during ad breaks. Video frames from the previous ad period overlap video in the current period.

App Name:
App Link on Amazon Appstore (found through Developer Console → Actions column in App List → View on Amazon.com): Paramount+, reproduced in Vega Video Sample App.

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

Using provided vpkg of Vega Video Sample App:

1. Launch the app on a Vega device.

2. Select the first title **“Empire”** under “Latest Hits” (a Widevine DASH VOD asset served through Google DAI with pre-roll + mid-roll ad breaks).

3. Let the pre-roll ad break play.

4. Once the main content period (Period 0) begins, **seek to ~645 seconds** (just before the first mid-roll break, which begins ~651 s).

5. Let playback run **continuously** through the entire mid-roll break (~651 s → ~757 s), which contains several back-to-back ads (each ~30 s, one DASH Period per ad).

6. Observe each ad-to-ad transition.

3. Observed Behavior

Explain what actually happened, noting any discrepancies or malfunctions.

The first ad end prematurely. During the second ad, you see the truncated frames from the first ad overlap the current ad part way through the ad. The overlap typically occurs on the following ads as well, with the last ad usually ending prematurely.

4. Expected Behavior

Describe what you expected the SDK to do under normal operation.

Seamless ad playback with no out of sequence frames.

4.a Possible Root Cause & Temporary Workaround

Fill out anything you have tried. If you don’t know, N/A is acceptable

AI analysis:
Suspected root cause (Vega native MSE): At DASH multi-period boundaries (per-period `timestampOffset`, per-period `appendWindowStart/End`), the native SourceBuffer appears to drop the trailing frames of the last video segment of a period (e.g., the final GOP / partial-segment / frames near `appendWindowEnd`) even though those frames are inside the append window. Audio (smaller segments) is unaffected. Desktop Chrome retains the same frames, so this is specific to the Vega native MSE/decoder pipeline, not the content or Shaka.

Workarounds attempted (no effect):

- Increased Shaka `streaming.rebufferingGoal` (0.01 → 4) and `bufferingGoal` (5 → 30): buffer filled far ahead but the same video-only hole persisted (confirming frames are dropped on append, not a buffering-goal problem).
- Set `streaming.inaccurateManifestTolerance` (0 → 1): did not close the boundary gaps.

5. Logs or crash report

(Please make sure to provide relevant logs as attachment)

For crash issues, please refer this guide for faster troubleshooting: Detect Where the App Crash Originates | Design and Develop Vega Apps

  • App/Device Logs

  • Crash Logs

  • Crash Report

  • For issues with Vega Studio Extension, please share log files from below folders:
    For v0.22+:

    ~/.vscode/extensions/amazon.vega-extension-<version>/ExtensionLogs
    ~/.vscode/extensions/amazon.vega-ui-extension-<version>/ExtensionLogs
    

    For v0.21 and earlier:

     ~/.vscode/extensions/amazon.kepler-extension-<version>/ExtensionLogs
     ~/.vscode/extensions/amazon.kepler-ui-extension-<version>/ExtensionLogs
    

6. Environment

Please fill out the fields related to your bug below:

  • SDK Version: 0.22.6150

  • App State: [Foreground]

  • OS Information: Please ssh into the device via vega exec vda shell (or kepler exec vda shell for v0.21 and earlier) and copy the output from cat /etc/os-release into the answer section below. Note, if you don’t have a simulator running or device attached, the command will respond with vda: no devices/emulators found

    NAME="OS"
    OE_VERSION="4.0.0"
    OS_MAJOR_VERSION="1"
    OS_MINOR_VERSION="1"
    RELEASE_ID="21"
    OS_VERSION="1.1"
    BRANCH_CODE="TV Ship"
    BUILD_DESC="OS 1.1 (TV Ship/27)"
    BUILD_FINGERPRINT="4.0.344088.0(3072cab629675a74)/27N:user/release-keys"
    BUILD_VARIANT="user"
    BUILD_TAGS="release-keys"
    BUILD_DATE="Thu Jun 18 06:50:08 UTC 2026"
    BUILD_TIMESTAMP="1781765408"
    VERSION_NUMBER="2101010002720"
    

7. Example Code Snippet / Screenshots / Screengrabs

Include any relevant code or component setup in React Native that can help reproduce the bug.

See media url and license server shared with Amazon contact.

:backhand_index_pointing_right: Playback Issues


If this is a playback issue, please provide your content URL, any pre-conditions (like geo-location), and let us know if it’s x86 or arm7.

See above.

Please share the following details in addition:_

  • Player SDK: [Shaka]
  • Player SDK Version: [4.16.13 and 4.8.5]
    • Audio Codecs: [AAC, ...]
    • Video Codecs: [h.264, mp4]
    • Manifest Types: [dash]

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

Shared with Amazon contact.

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.

Will share screen recording.

:backhand_index_pointing_right: 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.

<!-- Answer here if applicable  --> 

Hi @will.harris,

Thank you for the detailed bug report on the DASH multi-period playback frame overlap issue during ad breaks.

Our team is investigating this issue. We will provide an update as soon as we have more information.

We appreciate the thorough reproduction steps, AI-assisted root cause analysis, and the workarounds you’ve already attempted - this level of detail is extremely helpful for our investigation.

Thanks for helping us improve the Vega platform.

Warm regards,
Aishwarya