HEVC export silently drops the audio track in AME Beta 27.0.0.29 (H.264 and the 26.3.2 release are fine)

Exporting to HEVC (H.265) / MP4 in the beta produces a file with no audio stream at all. The Audio tab is set to AAC 320 kbps / 48 kHz / Stereo, the job reports "File Successfully Encoded", and the encoding log even records the audio settings — but there is no audio track in the output. No error, no warning. You only find out when you play the file.

The same source and settings work in Media Encoder 2026 (26.3.2.2), and H.264 works in the beta. It appears specific to the HEVC exporter.

Steps to reproduce: 1. Add a ProRes 422 XQ .mov with a PCM 16-bit 48 kHz stereo audio track to the queue. (Mine: 1080x1920, 24 fps.) 2. Set the output format to HEVC (H.265), MP4 container. 3. Set Video to Main 10, Rec. 2100 HLG 203 nits, VBR 1-pass, target 25 Mbps, Software Encoding. 4. In the Audio tab, confirm Audio Codec = AAC, 320 kbps, 48 kHz, Stereo. 5. Encode, then inspect the output with MediaInfo or ffprobe (or just play it).

Result: The MP4 contains only the HEVC video stream. There is no audio stream in the file. The queue reports "File Successfully Encoded" with no error or warning, and AMEEncodingLog.txt lists "- Audio: AAC, 320 kbps, 48 kHz, Stereo" for the job as though the track had been written. No AMEEncodingErrorLog.txt is produced.

Expected: The MP4 should contain an HEVC video stream and an AAC audio stream, as it does in Media Encoder 2026 (26.3.2.2) from the same source with the same settings.

System info Application: Adobe Media Encoder (Beta) v27.0.0.29 OS: Windows v10.0.26200, RAM: 189.67 GB GB, CPUs (logical): 32 GPU: NVIDIA GeForce RTX 4080, driver 32.0.16.1656 Comparison build: Adobe Media Encoder 2026 v26.3.2.2 (does not exhibit the bug)

ADDITIONAL FINDINGS

1. It's the codec, not the preset or the source. Same source file, same beta, same audio settings only the codec changed:

   HEVC Main 10 -> no audio stream H.264 High 10 -> aac (LC), 48000 Hz, stereo, 317064 bps correct

Since H.264 muxes audio into MP4 correctly in the same build, this rules out the MP4 container, the PCM source audio, and the preset.

2. It's the build. I ran the identical source through the beta and then the release about four minutes apart:

   Beta 27.0.0.29 -> video only Release 26.3.2.2 -> video + aac (LC), 48000 Hz, stereo, 317300 bps

3. Only the audio differs. I stream-copied the video out of both files and hashed it:

   beta MD5 = 2c1ec735203b9846d14395ed0efaeb37 release MD5 = 2c1ec735203b9846d14395ed0efaeb37

The video encode is byte-for-byte identical between the two builds. And the whole file-size difference is the missing track: 54,808,304 - 54,106,430 = 701,874 bytes, against 695,746 bytes predicted for a 317 kbps AAC track at 17.54 s.

4. Reproduced on two different source files, both times.

5. Because the log records the correct audio settings and reports success, the audio settings are being read and validated fine — the failure is further down, in the audio encode or mux stage of the HEVC path specifically.

6. Possibly relevant: in the working H.264 output, audio is stream 0 and video is stream 1. In the HEVC outputs, video is stream 0. The two exporters assemble their output differently, which might be where to look.

NOT YET TESTED HEVC to a MOV container, hardware vs. software encoding, a stock HEVC preset rather than my custom one, a source with AAC rather than PCM audio, and SDR rather than HLG output. Happy to run any of these if it helps.

I have the encoding logs, the application log, and full ffprobe dumps of the sources and every output glad to attach them.