Emby Android app crashes when playing FLAC files over mobile data (works fine with Wi-Fi or VPN)

[JMLGVaderMaul 0]

Hi everyone,

I’ve encountered a consistent issue when playing FLAC audio files through the Emby Android app while using mobile data (without VPN).
After several tests and log captures, I believe this could be a reproducible bug related to FLAC playback handling in the Android client.

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Issue description

When attempting to play FLAC files (both 16-bit and 24-bit) from the Emby Android app over a mobile data connection, the app immediately crashes once playback starts.

However:

• MP3 files play normally.

• Video playback also works fine.

• The same FLAC files play perfectly when using Wi-Fi or mobile data + VPN.

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Test scenarios and results

Mobile Data (no VPN)

• Network: 4G

• Result: App crashes instantly when playing FLAC.

• MP3 files play normally.

Mobile Data + VPN (to my home network)

• Result: FLAC plays perfectly without issues.

Wi-Fi (same LAN as server)

• Result: FLAC plays normally.

Wi-Fi hotspot (shared from another phone’s mobile data)

• Result: FLAC plays fine.

The issue only happens when streaming directly over mobile data without VPN.

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Server and client details

• Server: Emby Server 4.9.1.80 on Windows 10

• Client: Emby for Android 3.5.12

• Device: POCO X6 5G (Android 14)

• Playback type: Direct Play (no transcoding)

• Tested files:

  Working: Shakira – Que Me Quedes Tú (MP3)

  Crashing: 14 SymphonicSuite [AoT] Part2 - 5th - Apple Seed (FLAC)

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Relevant log information

Server log (embyserver.txt)

• No transcoding errors or codec issues appear during playback attempts.

• The server responds correctly to requests (HTTP 200 OK).

• When the client crashes, the connection simply drops — there is no “ffmpeg error” or “transcode failed” event, meaning the file was being streamed directly.

Android client log

• Shows normal app startup, but includes:

   

  Server discovery timed out waiting for response. Found 0 servers

  followed by the connection attempt to the remote server:

   

  http://domain.com:8096

• This indicates the Android app fails to maintain a stable connection or properly handle the FLAC stream over HTTP mobile data.

• No explicit crash exception is logged, suggesting a native player crash (ExoPlayer layer) when handling FLAC over an unstable or modified HTTP connection.

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Preliminary analysis

Based on the tests and logs:

• The issue appears to be a client-side crash in the Emby Android app during Direct Play of FLAC over HTTP using mobile data.

• The problem disappears when using:

  A VPN (which encapsulates and stabilizes the HTTP connection).

  Wi-Fi connections (LAN or shared hotspot).

• This suggests that mobile carriers might alter HTTP traffic, or that the app’s player has insufficient error handling for packet loss or header modification in FLAC streams.

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Temporary workarounds

• Use VPN: FLAC playback works fine over mobile data with a VPN.

• Use Wi-Fi: No issues observed.

• Force transcoding: Converting FLAC to MP3 or AAC for remote connections prevents the crash.

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Request

Could the Emby team confirm if this is a known issue with FLAC Direct Play on Android over mobile data (non-VPN)?
If needed, I can enable full debug logging and reproduce the crash again to capture additional details

embyserver_2.txt

[Abobader 3463]

Hello JMLGVaderMaul,

** This is an auto reply **

Please wait for someone from staff support or our members to reply to you.

It's recommended to provide more info, as it explain in this thread:

Thank you.

Emby Team

[Luke 42077]

Hi, we are looking into this. Thanks.

[shrublight 3]

I've started seeing the exact same issue.

On a side note, flac files play fine going through android auto, without using a VPN.

Using my phone on its own, with mobile data causes an instant crash.

[salmonter 0]

Same issue here.  Works over wifi and mp3s and videos work fine, no flac.

[VaderMaul 0]

Update – Temporary Solution Found

I found a temporary fix for the issue with FLAC files crashing the Emby Android app when using mobile data.

On the Android client side, under Settings → Playback, there are two options:

Remote streaming quality

Remote streaming quality (cellular)

Both were previously set to Auto.

After changing both settings to a fixed value — for example, 4 Mbps — the app no longer crashes when playing FLAC files over mobile data.

After applying this change, I tested several FLAC tracks in two Android devices, and they played successfully without the app closing.

It seems that when set to Auto, the Emby Android app may incorrectly handle bitrate negotiation or buffer management for FLAC streams under mobile data, causing the crash. Setting a fixed streaming bitrate stabilizes playback.

[Luke 42077]

HI, thanks for the info. We are working on this.

[Eidolf 3]

Hello, I hoped that it was fixed in the latest stable version 4.9.3.0 because of this sentence ( - Music transcoding fixes ), but it didn't change the flac behavior on my installation.
Am I right that it is still a undergoing problem and still a work in progress?

[sa2000 673]

2 hours ago, Eidolf said:

but it didn't change the flac behavior on my installation.
Am I right that it is still a undergoing problem and still a work in progress?

A problem has been seen on Emby for Android where for remote connections playback of flac files, only the first two tracks of the album fallback to transcoding and play ok - the third track does not play.  This is being investigated on this topic:  https://emby.media/community/index.php?/topic/145987-music-stops-playing-after-2-songs/

Update: The Emby for Android app (now at version 3.5.28) is not crashing when playing flac files. The current issue with remote connections playback of flac files, is that it is not switching to transcoded playback for album tracks after the second track

Edited February 2 by sa2000

[Eidolf 3]

Thanks for the link, on my last search in Dezember I only found and followed this topic not knowing there is a second one specific for the Android App.
I will have a look into the other topic.