How to Fix Audio Sync Problems in Plex Media Server

January 20, 2024

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Frustrated by videos in Plex where the audio doesn’t match up with the video? Out-of-sync audio can ruin the viewing experience. Thankfully, with the right troubleshooting, you can get Plex back in perfect sync.

This comprehensive guide covers 12 fixes to resolve Plex audio sync problems on devices like Roku, Nvidia Shield, Windows, and more. Read on to fix your audio delay issues for good.

Why Plex Audio Goes Out of Sync

Before diving into the solutions, it helps to understand what causes Plex audio sync problems in the first place:

  • Transcoding Issues: When Plex transcodes media into a format your device can play, errors during transcoding can throw off AV sync. This is one of the most common culprits.
  • Bad Metadata: If the media file itself has incorrect metadata like frame rate, it could lead to sync issues.
  • Connection Problems: An unstable internet connection while streaming can also impact synchronization.
  • Hardware Limitations: Older or underpowered Plex clients may struggle to maintain sync during playback.

The good news is that with the fixes outlined below, you can resolve lagging, delayed, or out-of-sync Plex audio on nearly any device.

12 Ways to Fix Plex Audio Out of Sync

Follow these top methods to get perfectly synced audio in Plex again:

1. Pause and Resume Playback

The simplest fix is to briefly pause the video then resume playback. For small, gradual sync drifts, this resets the sync effectively.

Plex Pause And Resume Playback

2. Skip Ahead and Rewind

Similarly, skipping forward 30 seconds then rewinding can recalibrate Plex’s audio sync without restarting playback fully.

Plex Skip Ahead And Rewind

3. Tweak Transcoding Quality

Changing transcoding quality settings can improve audio sync within Plex. Under server settings, try:

  • “Make My CPU Hurt” (improves accuracy over speed)
  • Lower resolutions like 720p/3Mbps bitrate
Plex Tweak Transcoding Quality

However, transcoding also worsens the problem on weaker Plex servers. Consider optimizing media instead.

4. Adjust Client Buffer Settings

Increasing buffer size allocates more memory to smooth out playback. Within Plex app settings, set buffers to:

  • Initial Buffer: 25MB
  • Pending Buffer: 50MB
  • Total Buffer: 75MB
Plex Adjust Client Buffer Settings

5. Disable Direct Play

With Direct Play enabled, try forcing Plex to transcode both video and audio streams instead. If that doesn’t resolve it, some users have had success switching to Plex alternatives like Emby.

Plex Disable Direct Play

6. Toggle Display Modes

Changing picture, color, sound modes in your playback device’s settings may also fix sync.

7. Reset App and Reinstall

Uninstalling and reinstalling the Plex app often resolves elusive audio delay issues as well.

Uninstall Plex

8. Adjust Audio Offset

Under Plex app settings, offset audio track directly to dial in perfect lip sync:

  • Alt + A = Increase audio delay
  • Alt + Shift + A = Decrease audio delay

9. Disable Audio Passthrough

Turning off Passthrough forces Plex to decode audio, avoiding sync issues caused by external devices.

Plex Disable Audio Passthrough

10. Update Plex Media Server

Updating to latest Plex version also helps resolve bugs causing audio drift.

11. Verify File Integrity

Use MediaInfo or FFmpeg to inspect files for corruption and bad metadata also throwing off AV sync.

12. Downgrade Plex

If a recent Plex update triggered sync delays, rolling back Plex server to an older version may help.

Key Takeaways and Preventative Tips

To recap, the top ways to fix Plex audio out of sync are:

  • Pause/skip playback to reset sync
  • Tweak transcoding quality higher
  • Increase buffer size
  • Disable Direct Play
  • Reinstall Plex app
  • Adjust audio offset
  • Disable Passthrough
  • Update Plex server
  • Validate media files
  • Downgrade Plex

Here are some pro tips to avoid sync problems in the future when using Plex:

  • Direct play media whenever possible instead of transcoding
  • Optimize files for direct streaming ahead of time
  • Enabling hardware acceleration in Plex can significantly improve transcoding speeds and synchronization. However, audio sync issues can still occur on weaker clients like the Steam Deck.
  • Use wired connections for faster speeds
  • Increase Plex buffer settings
  • Add pauses when sync drifts to reset

We hope this guide helps you banish annoying Plex audio sync issues for good. Let us know if you have any other fixes that worked for you!

Frequently Asked Questions

Here are answers to some common questions about fixing Plex audio out of sync:

Why does my Plex audio go out of sync randomly?

This is usually caused by on-the-fly transcoding errors or an unstable network connection interrupting streaming. Tweaking transcoding quality and buffers often helps.

Why is Plex audio sync fine for some files but not others?

If older files play fine but newer ones drift, it’s likely due to bad metadata or encoding issues in the problem files themselves. Analyzing them with tools like MediaInfo can help troubleshoot.

Does hardware acceleration fix Plex audio sync problems?

Enabling hardware acceleration in Plex can significantly improve transcoding speeds and synchronization. However, audio sync issues can still occur on weaker clients.

Should I downgrade or upgrade Plex if I have audio sync problems?

It depends – if sync issues appeared only after updating Plex, downgrading could help. But an upgrade can also resolve bugs causing sync delays.

Can adjusting picture settings fix audio sync issues?

Yes, particularly changing Game Mode to Standard Mode. Other display enhancements can indirectly throw off audio sync in Plex.

Why does Plex drift out of sync over time while watching?

This gradual sync drift is often caused by a mismatch between the timestamps in the media container and the actual stream duration. Resetting sync via pauses/skips helps.