When I enable audio passthrough, my 4K HEVC main 10 HDR material suddenly needs transcoding (video as well as audio). I don’t understand this. Video direct play should be unaffected by this setting I believe. However, when disabling passthrough the material plays just fine via direct stream (only audio gets transcoded of course). I saw someone on reddit reporting the same issue. Any ideas?
Relevant part of log while passthrough is turned on:
Mar 27, 2021 09:44:40.058 [0x7f0a9a7fc700] DEBUG - [Transcode] Found session GUID of bc82399822bb6586-com-plexapp-android in session start.
Mar 27, 2021 09:44:40.059 [0x7f0a9a7fc700] DEBUG - [Transcode] TranscodeUniversalRequest: using augmented profile Android
Mar 27, 2021 09:44:40.059 [0x7f0a9a7fc700] DEBUG - [Transcode] Downloading document http://127.0.0.1:32400/library/metadata/15477?includeBandwidths=1&offset=-1&X-Plex-Incomplete-Segments=1&X-Plex-Session-Identifier=bc82399822bb6586-com-plexapp-android
Mar 27, 2021 09:44:40.059 [0x7f0a9a7fc700] DEBUG - [Transcode] Auth: authenticated user 1 as victor_peeters
Mar 27, 2021 09:44:40.070 [0x7f0a9a7fc700] DEBUG - [Transcode] It took 0.000000 ms to retrieve 119 items.
Mar 27, 2021 09:44:40.071 [0x7f0a9a7fc700] DEBUG - [Transcode] We're going to try to auto-select an audio stream for account 1.
Mar 27, 2021 09:44:40.071 [0x7f0a9a7fc700] DEBUG - [Transcode] Selecting best audio stream for part ID 32622 (autoselect: 1 language: nl)
Mar 27, 2021 09:44:40.071 [0x7f0a9a7fc700] DEBUG - [Transcode] Audio Stream: 107094, Subtitle Stream: 122956
Mar 27, 2021 09:44:40.073 [0x7f0a9a7fc700] DEBUG - [Transcode] Scaled up video bitrate to 71496Kbps based on 4.500000x fudge factor.
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Selected protocol hls; container: mkv
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: analyzing media item 22015
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Aladdin (2019): Direct Play is disabled
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Aladdin (2019): media must be transcoded in order to use the hls protocol
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Aladdin (2019): selected subtitle cannot be converted to a compatible format, burning into video stream
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Aladdin (2019): avoiding video remux due to burned subtitle stream
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Aladdin (2019): no remuxable profile found, so video stream will be transcoded
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Cannot direct stream video stream due to profile or setting limitations
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] Scaled up video bitrate to 71496Kbps based on 4.500000x fudge factor.
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Cannot direct stream audio stream due to codec truehd when profile only allows eac3
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] MDE: Aladdin (2019): selected media 0 / 22015
Mar 27, 2021 09:44:40.074 [0x7f0a9a7fc700] DEBUG - [Transcode] Streaming Resource: Session 0x7f0ac03bffc0:bc82399822bb6586-com-plexapp-android changed transcode slot usage to used. Used slots is now 1
Log when passthrough is enabled. Video and subs are played by direct stream, audio gets transcoded.
Mar 27, 2021 09:52:29.248 [0x7f0a5b7fe700] DEBUG - [Transcode] Found session GUID of bc82399822bb6586-com-plexapp-android in session start.
Mar 27, 2021 09:52:29.249 [0x7f0a5b7fe700] DEBUG - [Transcode] TranscodeUniversalRequest: using augmented profile Android
Mar 27, 2021 09:52:29.249 [0x7f0a5b7fe700] DEBUG - [Transcode] Downloading document http://127.0.0.1:32400/library/metadata/15477?includeBandwidths=1&offset=-1&X-Plex-Incomplete-Segments=1&X-Plex-Session-Identifier=bc82399822bb6586-com-plexapp-android
Mar 27, 2021 09:52:29.249 [0x7f0a5b7fe700] DEBUG - [Transcode] Auth: authenticated user 1 as victor_peeters
Mar 27, 2021 09:52:29.261 [0x7f0a5b7fe700] DEBUG - [Transcode] It took 0.000000 ms to retrieve 119 items.
Mar 27, 2021 09:52:29.261 [0x7f0a5b7fe700] DEBUG - [Transcode] We're going to try to auto-select an audio stream for account 1.
Mar 27, 2021 09:52:29.262 [0x7f0a5b7fe700] DEBUG - [Transcode] Selecting best audio stream for part ID 32622 (autoselect: 1 language: nl)
Mar 27, 2021 09:52:29.262 [0x7f0a5b7fe700] DEBUG - [Transcode] Audio Stream: 107094, Subtitle Stream: 122956
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Selected protocol hls; container: mkv
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: analyzing media item 22015
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): Direct Play is disabled
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): media must be transcoded in order to use the hls protocol
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): no direct play video profile exists for http/mkv/hevc
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): no direct play video profile exists for http/mkv/hevc/truehd
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): selected sidecar subtitle stream cannot be direct played
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): no direct play video profile exists for http/mkv/hevc/ac3
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): selected sidecar subtitle stream cannot be direct played
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Cannot direct stream audio stream due to codec truehd when profile only allows aac
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] MDE: Aladdin (2019): selected media 0 / 22015
Mar 27, 2021 09:52:29.263 [0x7f0a5b7fe700] DEBUG - [Transcode] Streaming Resource: Added session 0x7f0a741a9590:bc82399822bb6586-com-plexapp-android
Mar 27, 2021 09:52:29.264 [0x7f0a5b7fe700] DEBUG - [Transcode] Streaming Resource: Reached Decision id=15477 codes=(General=1001,Direct play not available; Conversion OK. Direct Play=3000,App cannot direct play this item. Direct play is disabled. Transcode=1001,Direct play not available; Conversion OK.) media=(id=22015 part=(id=32622 decision=transcode container=mkv protocol=hls streams=(Video=(id=107093 decision=copy width=3840 height=2160) Audio=(id=107094 decision=transcode bitrate=774 encoder=aac channels=6 rate=48000) Subtitle=(id=122956 decision=copy languageCode=dut location=embedded))))
