Emby Android on GoogleTV DV Bug

[LuckyQuantity 0]

Hey guys, I’m new here

I use Emby on my Google TV streamer and watch on my Sony OLED.

As soon as I play Dolby Vision content (Profile 5), the black bars appear slightly gray.

With SDR and HDR10, these issues do not occur in Emby.

Is there a solution for this, or can I provide more details to help find one? Feel free to ask.

Cheers

 

[Sammy 790]

 

[Luke 42077]

@LuckyQuantity

 

Hi there, let's look at an example. Please attach the information requested in how to report a media playback issue. Thanks!

 

[LuckyQuantity 0]

Thank you. I checked the log file myself. There’s no error. ExoPlayer is running with hardware decoding. Emby is also doing everything correctly.

That made me suspicious, so I tried using an external player: JustPlayer, which works perfectly.
 

Technical Bug Report

Subject: Raised black levels in letterbox bars during Dolby Vision Profile 5 playback on Google TV Streamer (Android 14)

Issue Description:

When playing Dolby Vision Profile 5 content (dvhe.05.06) using the built-in Emby standard player (ExoPlayer), the black letterbox bars (top and bottom) are not rendered as "perfect black" (OLED pixels off). Instead, they appear as a glowing dark grey.

Environment:

• Device: Google TV Streamer 4K (Model 2024).

• OS: Android 14.

• Display: Sony A80L OLED (HDMI Signal Format set to "Enhanced format (Dolby Vision)").

• App: Emby for Android TV (using internal ExoPlayer).

Technical Details & Log Analysis:

• Media Info: The file is identified as Dolby Vision Profile 5.

• Refresh Rate: The player correctly identifies the source at 23.976 fps and attempts a refresh rate switch.

• The Bug: Although the MediaCodecVideoRenderer is enabled, the ExoPlayer fails to correctly flag the "black level" for the non-video surface areas (the bars). This results in "raised blacks," where the display receives a signal that prevents OLED pixels from turning off completely.

Comparison / Steps to Reproduce:

1. Play any Dolby Vision Profile 5 file via the internal Emby player -> Result: Grey bars.

2. Play the same file via an external player (e.g., "Just Player" using androidx.media3) on the same device -> Result: Perfect black bars.

Conclusion:

This is a software-side issue regarding how Emby’s ExoPlayer implementation handles the video surface and Dolby Vision metadata on Android 14. The system's hardware decoder works correctly, as proven by other players.

[LuckyQuantity 0]

Technical Solution: Fixed Raised Blacks & Frame Rate Switching on Google TV Streamer

Issue:

Raised black levels (grey letterbox bars) during Dolby Vision Profile 5 playback, specifically on the Google TV Streamer (Android 14) connected to a Sony OLED (A80L).

The Conflict:

When the system-level setting "Match content frame rate" is enabled in the Google TV Streamer settings, it interferes with Emby's internal ExoPlayer refresh rate switching. This conflict causes the Dolby Vision "Surface" to render incorrectly, failing to signal a true black (0 nit) value to the OLED for the letterbox areas.

The Solution (Workaround):

1. Google TV Streamer Settings: Go to Settings > Display & Sound > Match content frame rate and set it to OFF.

2. Emby App Settings: Ensure that "Display mode switching" (or Refresh Rate Switching) is remains ENABLED within the Emby app playback settings.

Result:

By disabling the system-level override, Emby's ExoPlayer gains direct control over the HDMI handshake. The player successfully switches the Sony TV to 24p, and the Dolby Vision metadata is passed correctly without lifting the black levels. The letterbox bars remain perfectly black (pixels off).

Recommendation for Developers:

There appears to be a regression or conflict in how Android 14's global "Match Content" API interacts with the ExoPlayer's private surface rendering for Dolby Vision. Emby developers should investigate if the app is fighting the OS for control over the display surface when both settings are active.

[Luke 42077]

Hi, thanks for following up. We'll take a look at that.