PMS transcoding audio, how to avoid this?

Plex Media Server NAS & Devices
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Server Version#: 1.16.1.1291
Player Version#: LG webos latest version.

Hi Guys,
When I play movies that have directors commentary in them as well. Plex tends to transcode the actual audio for the movie (which leads to constant buffering) when i select direct play 5.1 there is no buffering but the audio is the stupid directors commentary.
How can I set it up so that it just direct plays the normal sound for the movie rather than the directors commentary?

In other words, how can I just set it up to play AC3 audio by default? which does not seem to require transcoding.

Thanks!

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You have to pick an audio stream that can be direct played by the Plex client. Check the technical specification for your TV set and choose audio tracks which are supported by your TV.

Plex defaults to the first audio track in the container (*). So, for example, if your movie has both TrueHD and AC3 audio, remux the file so the AC3 audio is the first audio track.

Blu-ray movies with dts-HD audio must also include a standard dts audio track. Blu-ray movies with TrueHD audio must also include a standard AC3 audio track. So, in theory, you should have access to an audio track your TV can play (if your TV supports both AC3 & dts).

If you do not have access to an audio stream your TV can direct play, you can use a combination of tools such as XMedia Recode (transcode/remux), Handbrake (transcode), MKVToolNix (remux, MKV only), and Subler (remux, MP4 only, Mac only) to transcode/remux available audio as needed.

Note: Watch out for subtitles. Some (all?) Plex Smart TV clients do not support image based subtitles such as PGS & VOBSUB. Enabling those subtitles forces a transcode. Also, be aware that enabling SRT subtitles while audio is transcoding will also force a video transcode. SubTitle Edit is a good tool for translating PGS/VOBSUB to SRT. The OCR process can be laborious, but it is the best tool I’ve found to accomplish the translation.

Example:

I have a LG B7 OLED. It direct plays AAC/AC3/dts/dts-HD audio streams up to 5.1 channels. Any 7.1 audio stream is transcoded, as is any TrueHD audio stream, since the TV does not support those audio formats.

So, when watching a movie using the LG Plex client, I specifically choose a supported audio stream. I avoid dts-HD MA 7.1 & TrueHD audio streams as they always transcode.

The Plex LG client is also susceptible to the previously mentioned subtitle condition. Therefore, I do not enable PGS/VOBSUB subtitles, or SRT when audio is transcoding, to avoid video transcodes.

(*) Your PMS language settings may have some effect on which audio track is selected first. I’m not sure what would happen if, for example, PMS was set to prefer English and a non-English audio track was present before an English audio track in the movie.

3 Likes
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Dear Fordguy61
Thanks for your response. The second part of your post is really enlightening for me. I have the same TV Lg Oled 65B7v and I have noticed exactly what you mentioned. When it is a 7.1 stream it will start transcoding (although when running through the photos and videos native lg app it doesn’t transcode or lag even with the 7.1) and TrueHD is also transcoded. You said you avoid DTS hd 7.1, however DTS hd (non 7.1) works fine.
The reason I asked is that in some films the 7.1 is the main audio for the movie and the AC3 5.1 is the directors commentary, so you end up with a buttery smooth movie but with the unneeded directors commentary! You recommend switching their audio tracks?

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Another question that I have is… I have a Synology DS218+ which seems to have a strong enough hardware (as noted on Plex nas compatibility list) to be able to transcode on the fly? why the buffering then? any settings I might be missing?

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I am not recommending you play the commentary tracks.

I am recommending you play an AC3 or dts (non-HD) version of the primary audio track, which is included on Blu-ray discs (Blu-ray standard). You may have to re-rip the disc if you did not include the AC3/dts version in your current rip.

If you do not have access to the original disc, and the movie does not have an AC3 or dts version of the primary audio track, you can create one using the tools mentioned in my first reply (ex: Transcode TrueHD to AC3 then mux back into current movie).

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A funny and unfortunately ironic thing is that the lg tv’s own player is able to play the same movie off PMS without any hiccups or transcoding. it even says ‘truehd 7.1’ with no transcoding (mocking me!)

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see @ [INFO] Plex, 4k, transcoding, and you - aka the rules of 4k

especially the questions/answers section

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Fordguy61 I have got THE solution for you mate.
Get one of these and plug it into the usb 3 port of your tv. It doesn’t show as if the tv is connected but it bloody works!

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If I may add?

That little rascal works flawlessly with Linux. I have one and have been using it for the part 1+ years. (Fedora dropped support for the RealTek ethernet chip in my All-in-One desktop).

I keep it as my spare now because I just got the new Aquantia NBaseT 5GbE USB 3.0

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Damn someone should have touted this solution before! My life is complete now (atleast my ocd of wanting everything to run smoothly)
I have the urge to order another one incase they run out of supply lol

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