New Mobile App (Android) Won't Play AAC with more than 2 channels

Simon.Roth · May 7, 2025, 10:25pm

Server Version#: 1.41.6.9685
Player Version#: Android - 2025.15.0 (966828394)

I recently noticed that then new Mobile App (Android) will not play a file if the audio codec is AAC and it has a channel count over 2. It returns the below error on any file with AAC 5.1. I have tested across multiple files and received the same result every time. If I reencode these same files to be AAC 2.0 (with no other changes) they will play without issue. Also, if I reencode them to another codec, such as AC3 and keep them at 5.1 they tend to work as well.

I have also included a log snippet for such an event below.

"MediaCodecAudioRenderer error, index=3, format=Format(1, null, null, audio/mp4a-latm, aac, -1, english, [-1, -1, -1.0, null], [6, 48000]), format_supported=YES"

05/07/2025 17:28:59:361 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [CastScreen] Start Casting - Cast Data found
05/07/2025 17:28:59:362 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [Vizbee] Casting content /library/metadata/367314
05/07/2025 17:28:59:366 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [Vizbee] Playing Locally - Not connected to TV
05/07/2025 17:28:59:382 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [CastScreen] Fallback - Original path found
05/07/2025 17:28:59:475 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [PlaybackSession] Updating session for new item.
05/07/2025 17:28:59:517 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Loading native video player.
05/07/2025 17:28:59:517 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Selecting subtitle stream:  undefined
05/07/2025 17:28:59:517 [Simon5d21eaaf0aae5410-com-plexapp-android] ERROR [NativeVideo] Video size changed, but view size unknown.
05/07/2025 17:28:59:519 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [MediaDecisionEngine] Running initial load
05/07/2025 17:28:59:519 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaDecisionEngine] Refreshing decision. Reason: Initial load startOffsetMs: 0
05/07/2025 17:28:59:570 [Simon5d21eaaf0aae5410-com-plexapp-android] ERROR [NativeVideo] Unable to change dimensions, size invalid.
05/07/2025 17:28:59:855 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaInspector] Selected video quality as original.
05/07/2025 17:28:59:855 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaInspector] Selected video quality as original, whilst session quality is undefined.
05/07/2025 17:28:59:855 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [PlaybackOptions] Updating session quality to original (max bitrate undefined).
05/07/2025 17:28:59:855 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaInspector] Selected video quality as original.
05/07/2025 17:28:59:855 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaInspector] Selected video quality as original, whilst session quality is original.
05/07/2025 17:28:59:894 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE][Video] hevc is supported by platform.
05/07/2025 17:28:59:900 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE][Video] hevc is supported by platform.
05/07/2025 17:28:59:904 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE][Audio] aac is supported by platform.
05/07/2025 17:28:59:907 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE][Audio] aac is supported by platform.
05/07/2025 17:28:59:907 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE] Application decision, directPlay: true, directStreamVideo: true, directStreamAudio: true
05/07/2025 17:28:59:907 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO   videoStream: {
  "id": 3610069,
  "streamType": 1,
  "default": true,
  "codec": "hevc",
  "index": 0,
  "bitrate": 1550,
  "bitDepth": 8,
  "chromaLocation": "left",
  "chromaSubsampling": "4:2:0",
  "codedHeight": 1088,
  "codedWidth": 1920,
  "colorPrimaries": "bt709",
  "colorRange": "tv",
  "colorSpace": "bt709",
  "colorTrc": "bt709",
  "frameRate": 23.976,
  "height": 1080,
  "level": 120,
  "profile": "main",
  "refFrames": 1,
  "scanType": "progressive",
  "width": 1920,
  "displayTitle": "1080p (HEVC Main)",
  "extendedDisplayTitle": "1080p (HEVC Main)"
}
05/07/2025 17:28:59:907 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO   audioStream: {
  "id": 3610070,
  "streamType": 2,
  "selected": true,
  "default": true,
  "codec": "aac",
  "index": 1,
  "channels": 6,
  "bitrate": 192,
  "language": "English",
  "languageTag": "en",
  "languageCode": "eng",
  "profile": "lc",
  "samplingRate": 48000,
  "displayTitle": "English (AAC 5.1)",
  "extendedDisplayTitle": "English (AAC 5.1)"
}
05/07/2025 17:28:59:907 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO   subtitleStream: none
05/07/2025 17:28:59:911 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE][Audio] aac is supported by platform.
05/07/2025 17:28:59:918 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE][Video] hevc is supported by platform.
05/07/2025 17:28:59:920 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaInspector] Selected video quality as original.
05/07/2025 17:28:59:920 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaInspector] Selected video quality as original, whilst session quality is original.
05/07/2025 17:28:59:945 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE] Server decision, directPlay: true, directStreamVideo: true, directStreamAudio: true
05/07/2025 17:28:59:945 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO   reason: Direct play OK.
05/07/2025 17:28:59:945 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE] Direct play is supported for this media item.
05/07/2025 17:28:59:945 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE] Playing audio as aac.
05/07/2025 17:28:59:945 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MDE] Playing video as hevc.
05/07/2025 17:28:59:946 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [MediaDecisionEngine] Decision has been refreshed. Reason: Initial load startOffsetMs: 0
05/07/2025 17:28:59:973 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Unloading native video player.
05/07/2025 17:28:59:973 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Loading native video player.
05/07/2025 17:28:59:973 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Selecting initial audio stream at index 1.
05/07/2025 17:28:59:973 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Selecting subtitle stream:  undefined
05/07/2025 17:28:59:987 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [Metrics] Playback metric event playback:itemstart recorded: {
  "offset": 0
} {
  "startTime": 0,
  "playbackCount": 1,
  "codecs": {
    "audioCodec": "aac",
    "subtitleCodec": null,
    "videoCodec": "hevc"
  },
  "auto": null,
  "groupID": null,
  "groupIndex": null,
  "itemIndex": null,
  "page": null
} {
  "duration": 3758,
  "drm": null,
  "type": "episode",
  "provider": "com.plexapp.plugins.library"
}
05/07/2025 17:29:00:005 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [NativeVideo] Video size changed to 2560x1440
          at 320/0,
          original size was 1920x1080 (1),
          view was 3200x1440.
05/07/2025 17:29:00:444 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [Metrics] Playback metric event playback:failure recorded: {
  "error": "MediaCodecAudioRenderer error, index=3, format=Format(1, null, null, audio/mp4a-latm, aac, -1, english, [-1, -1, -1.0, null], [6, 48000]), format_supported=YES"
} {
  "bufferingCount": 1,
  "bufferingDuration": 733,
  "bufferingDurationUnit": "ms",
  "secondsWatched": 0,
  "percentWatched": 0,
  "numSeeks": 0,
  "bufferDurationFromSeeks": 0,
  "startTime": 0,
  "playbackCount": 1,
  "codecs": {
    "audioCodec": "aac",
    "subtitleCodec": null,
    "videoCodec": "hevc"
  },
  "auto": null,
  "groupID": null,
  "groupIndex": null,
  "itemIndex": null,
  "page": null
} {
  "duration": 3758,
  "drm": null,
  "type": "episode",
  "provider": "com.plexapp.plugins.library"
}
05/07/2025 17:29:01:209 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO [PlaybackSession] Unloading session
05/07/2025 17:29:01:219 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [Metrics] Playback metric event playback:itemend recorded: {
  "result": "stopped"
} {
  "bufferingCount": 1,
  "bufferingDuration": 733,
  "bufferingDurationUnit": "ms",
  "secondsWatched": 0,
  "percentWatched": 0,
  "numSeeks": 0,
  "bufferDurationFromSeeks": 0,
  "startTime": 0,
  "playbackCount": 1,
  "codecs": {
    "audioCodec": "aac",
    "subtitleCodec": null,
    "videoCodec": "hevc"
  },
  "auto": null,
  "groupID": null,
  "groupIndex": null,
  "itemIndex": null,
  "page": null
} {
  "duration": 3758,
  "drm": null,
  "type": "episode",
  "provider": "com.plexapp.plugins.library"
}
05/07/2025 17:29:01:227 [Simon5d21eaaf0aae5410-com-plexapp-android] DEBUG [Metrics] Playback metric event playback:sessionend recorded: {} {
  "bufferingCount": 1,
  "bufferingDuration": 733,
  "bufferingDurationUnit": "ms",
  "secondsWatched": 0,
  "percentWatched": 0,
  "numSeeks": 0,
  "bufferDurationFromSeeks": 0,
  "startTime": 0,
  "playbackCount": 0,
  "codecs": {
    "audioCodec": "aac",
    "subtitleCodec": null,
    "videoCodec": "hevc"
  },
  "auto": null,
  "groupID": null,
  "groupIndex": null,
  "itemIndex": null,
  "page": null
} {
  "duration": 3758,
  "drm": null
}
05/07/2025 17:29:01:234 [Simon5d21eaaf0aae5410-com-plexapp-android] INFO Unloading native video player.

boblinthewild · May 8, 2025, 5:36am

I know this doesn’t help you, but I can play MP4 videos with AAC5.1 on a Samsung Tab A9+ without a problem. Also running 2025.15, though my server is version is newer (1.41.7.9749). Not sure if the server version or the physical Android device type is making for a different experience.

I did notice ‘mp4a’ in the error message you provided. Is it possible the video is encoded as m4a, which I believe only supports two-channel AAC audio?

Otherwise, hopefully your logs provide some clues for Support.

Simon.Roth · May 18, 2025, 12:35am

Thanks, all my files are h.265 (HEVC) in .mkv containers.

This issue didn’t exist in the previous mobile app veraion and all files would play normally.

I’m not sure what changed, but something did for sure.

boblinthewild · May 18, 2025, 1:38am

FWIW, I just tried watching a h.265/AAC 5.1/mkv video and it played fine (now on Android 2025.16). Again, hard to say why our experiences are different, so hopefully the support folks figure it out.

ChristianKent · May 29, 2025, 10:57am

I’m getting this also. Did you ever get it to work?

ChristianKent · May 29, 2025, 2:04pm

Is this only in the new app? Coz it looks like I can fix this by converting AAC 6 channels to EAC3.

Basically for multichannel, Advanced Audio Codec Low Complexity (A_AAC-2) will not play but Advanced Audio Codec Low Complexity with Spectral Band Replication (A_AAC-5) will.

Also, 2 channels don’t have this problem. And it all works in the desktop app and roku, so this is only on the android app.

ChristianKent · May 30, 2025, 12:59am

I figured this out.

Check the file mediainfo output and it will show that the audio channel layout for that 6 channel AAC-LC is L R C Cb Lb Rb and the expected is C L R Ls Rs LFE. You’ll know it’s not correct because most interpreters will read it as undefined or 6.0 channels instead of 5.1 channels.

github.com/HaveAGitGat/Tdarr_Plugins

Defect in FFMPEG corrupts AAC 5.1 6-channel layout

opened 08:52PM - 15 Dec 23 UTC

zkhcohen

**Affected Plugin:** Tdarr_Plugin_JB69_JBHEVCQSV_MinimalFile (NOTE: There …may be many more plugins affected by this issue) **Bug:** If '-ac 6' is not added as an option when transcoding, downmixing or converting to AAC 5.1 audio, the channel layout will be invalid. The expected channel layout is 'C L R Ls Rs LFE' however FFMPEG produces the 'hexagonal audio' layout 'L R C Cb Lb Rb' which is largely unsupported and causes many video players to crash, including certain versions of VLC, and ExoPlayer on CCwGTV. Googling "L R C Cb Lb Rb" will return dozens of additional reports of this issue, but none have been directly attributed to a Tdarr plugin until now. **Solution:** There are various potential implementations so I'll defer to someone with more experience, but ensuring that '-ac 6' is set in any scenario when transcoding, downmixing or converting to AAC 5.1 (6 channel) audio is the solution. Here's what I implemented: ```javascript if (file.ffProbeData.streams[audioIdx].channels == 6) { bolDownMixAudio = true; } ``` ...which will trigger that option to be set at the bottom of the plugin code: ```javascript if (bolDownMixAudio) { strFFcmd += ` -ac ${audioNewChannels} `; } ``` --- **Solution to fix your files affected by this bug:** I've created a plugin based off of Tdarr_Plugin_JB69_JBHEVCQSV_MinimalFile which fixes the issue on any affected files in your library. [You can download the plugin here.](https://www.mediafire.com/file/gwjk67siplf8xx0/Tdarr_Plugin_zkhcohen_audio_channel_fix.zip/file) It uses several conditions to check whether it should act upon a given file: 1. The original plugin must've been executed against the file (checks metadata / file format). 2. There must only be a single audio track. 3. The audio track must have 6 channels. 4. FFMPEG must indicate that the channel layout is 'undefined' (if the channel layout _was_ correct, it would return '5.1'). The plugin uses 'channelmap' to re-map the channels to their appropriate locations, outputting it as an AAC with the original bitrate, and merely copying the video and subtitles tracks. If someone has a more efficient way of re-mapping the _channel metadata_, please let me know. All attempts to simply remap the layout metadata failed due to FFMPEG's lack of support for this channel layout.

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