# TrueHD/MLP audio transcodes fail — transcoder writes \`.mlp\` files into EAE 

**URL:** <https://forums.plex.tv/t/truehd-mlp-audio-transcodes-fail-transcoder-writes-mlp-files-into-eae/940690>\
**Category:** Plex Media Server\
**Tags:** server-mac, apple-tv\
**Created:** [July 16, 2026, 2:29pm UTC](https://forums.plex.tv/t/truehd-mlp-audio-transcodes-fail-transcoder-writes-mlp-files-into-eae/940690 "2026-07-16T14:29:57Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![shanehinzman](https://avatars.discourse-cdn.com/v4/letter/s/dfb087/32.png) [@shanehinzman](https://forums.plex.tv/u/shanehinzman)\
**Post date:** [July 16, 2026, 2:29pm UTC](https://forums.plex.tv/t/truehd-mlp-audio-transcodes-fail-transcoder-writes-mlp-files-into-eae/940690/1 "2026-07-16T14:29:57Z")

</div>

## Environment

- **PMS:** 1.43.3.10828-00f62d37d (macOS, darwin-aarch64), auto-updated from 1.43.2.10687-563d026ea on 2026-07-15
- **Host:** Mac Studio (Mac13,1, M1 Max), macOS 26.5.1 (build 25F80)
- **EAE codec package:** `EasyAudioEncoder-0dd4de86f2b9bb8b9b397a90-darwin-aarch64` (also re-downloaded fresh from [downloads.plex.tv](http://downloads.plex.tv) — identical behavior)

## Summary

After updating to 1.43.3.10828, **every transcode of TrueHD (and MLP) audio fails**. The transcoder log fills with thousands of repeats of:

```auto
ERROR - [Req#.../Transcode/...] [truehd_eae @ 0x...] error reading output: -1313558101 (Unknown error occurred)
ERROR - [Req#.../Transcode/...] [aist#0:1/truehd @ 0x...] Error submitting packet to decoder: Unknown error occurred

```

Clients spin forever on playback start. This also affects scheduled intro/credits detection on TrueHD items, which floods and rotates away all [server logs](https://support.plex.tv/articles/200250417-plex-media-server-log-files/) (~10 MB every 2–3 minutes while a job is stuck).

EAC3 paths (`eac3_eae` encode and decode) are **not** affected. The same EAE build transcoded TrueHD fine on 1.43.2.10687 until the moment of the update, so the regression is on the transcoder side of the handoff.

## Root cause (isolated repro outside PMS)

Running EasyAudioEncoder standalone (so its stdout is visible) and invoking the 1.43.3 Plex Transcoder against it directly:

```auto
cd /tmp/eae-test && /path/to/Codecs/EasyAudioEncoder-.../EasyAudioEncoder/EasyAudioEncoder & # creates its watch dirs in cwd

EAE_ROOT=/tmp/eae-test "/Applications/Plex Media Server.app/Contents/MacOS/Plex Transcoder" \
  -codec:1 truehd_eae -eae_prefix:1 test_ -t 10 \
  -i "input-with-truehd.mkv" -map 0:1 -codec:a pcm_s16le -y /tmp/out.wav

```

Observed:

1. The transcoder drops its intermediate input files into `Convert to WAV (to 8ch or less)/` with an **`.mlp` extension** , e.g. `test_13058-0-18197.mlp`
2. EAE prints **`No data written!`** for each file and never produces WAV output
3. ffmpeg then loops `[truehd_eae] error reading output: -1313558101` (-1313558101 is the FourCC “UNKN”)

So the 1.43.3 transcoder writes an intermediate format/naming for TrueHD that the currently-distributed EAE build does not accept. Either the transcoder should go back to the extension/container EAE expects, or a matching EAE build needs to ship — `downloads.plex.tv/codecs/.../EasyAudioEncoder-darwin-aarch64-standard.zip` still serves version `0dd4de86f2b9bb8b9b397a90` for this PMS build.

## What I ruled out

- Clean PMS restart (fresh `EAE_ROOT`, fresh `Plex EAE Service` process) — no change
- Deleting `Codecs/EasyAudioEncoder*` and letting PMS re-download — no change (same version served)
- Disk space (773 GB free), permissions, quarantine/codesign on the EAE binary — all fine
- EAC3 encode/decode through the same standalone EAE instance — **works** , so the EAE service itself is alive and the watchfolder handshake is fine for other codecs

## Impact

Any client that can’t direct-play TrueHD (Apple TV etc.) fails on all TrueHD content; nightly analysis tasks on TrueHD items burn CPU and destroy log history via rotation.