Why PLEX Is Not Direct Playing Your Media

If you run your own Plex Media Server and your playback experience is plagued by long buffering times or intermittent stuttering, this blog post is for you.

As the name Plex Media Server already implies, Plex is a two-component solution featuring a server and clients. If Direct Play is your goal (which it should be, at least for local network streaming) you don’t need to worry about your server’s hardware too much. The right client setup is much more important than a beefy server.

First, let’s look at the three different playback modes:

• Direct Play
• Direct Stream
• Transcoding

Direct Play means that your server is transferring the video file as it is over the network. Your client is handling the decoding of the video locally. This only works if your client supports playing back the video and audio format of the file. Direct Play offers the best audio and video quality and the fastest skip forward/backward times. Buffering times are almost non-noticeable, and you can skip forward instantly.

Direct Stream means that only the video is transferring directly but audio is being transcoded. In that case, Plex extracts the audio, transcodes it to something which is compatible with your client and then muxes the converted audio back into the video container before it’s streamed to the client. This typically happens when the video file contains lossless audio tracks such as Dolby TrueHD or DTS:X but the client doesn’t support playback of lossless audio. Transcoding audio does not require a lot of power and doesn’t even need a dedicated GPU since it’s not touching the video. In fact, transcoding is done on the CPU. However, since the audio needs to be extracted, converted, and put back into the video file, Direct Stream will introduce some noticeable buffer times when playback is started or when you skip forward/backward.

Transcoding happens when either the video or the video and the audio are incompatible with the client. In that case, the entire video is live transcoded (converted) by the Plex server. Transcoding video requires much more processing power than just transcoding audio. If you must/want to use video transcoding, I highly recommend paying for the Plex Pass and make sure that your server is running on a system which supports hardware accelerated transcoding (use GPU instead of CPU).

Plex Transcoding Settings

Plex has an official article about playback modes as well.

Reasons for Content not Direct Playing

The most common reason your Plex server is not direct playing media is actually because of the audio and not the video format. While most Plex clients have no issue direct playing lossy (compressed) formats such as Dolby Digital (AC3) or Dolby Digital Plus (EAC3 (enhanced)), they are not compatible with lossless (uncompressed) formats such as Dolby TrueHD, DTS-HD, DTS-HD-MA or DTS:X. Therefore, Plex will automatically direct stream and not direct play such content.

What You need for Direct Play

To be able to direct play these high-quality audio formats, you’ll need the following:

• A soundbar/receiver which supports decoding of these formats
• A TV with HDMI 2.1 and eARC (Enhanced Audio Return Channel)
• A client device like a TV or a streaming box which supports audio passthrough or decoding of Dolby TrueHD and DTS-HD/X.

If your TV can decode or pass through Dolby TrueHD and DTS-HD/X formats via eARC and your soundbar supports these formats as well, you should be able to direct play all your media.

However, many TVs, including some LG OLED models don’t support DTS formats completely and don’t even pass it through to a receiver. I have an LG OLED C1 (2021) which unfortunately only supports Dolby Atmos TrueHD but no DTS at all which means that any DTS audio will always be transcoded if media is being played back through the Plex for LG app. Luckily, LG has added back DTS support to their TVs in 2023 and kept it in their 2024 models.

Anyway, don’t take my word for it and always make sure to check what formats are supported for audio passthrough yourself before buying a new TV. Sadly, not all manufacturers include all the details about which formats are supported on their websites, but I’ve found that RTINGS is always a reliable source.

RTINGS Info about Audio Passthrough Formats for LG C1

So, if your TV doesn’t support DTS too and if you want to direct play DTS audio, you’ll need a streaming box which supports audio passthrough. The only mainstream players which I know of that support audio passthrough currently are:

• Xbox One S | X
• Xbox Series S | X
• Nvidia Shield (2019 models)

Unfortunately, the Apple TV 4K does not support audio passthrough at this time. Hopefully, Apple will add that in a future software update or version.

With an external device, the HDMI output of your streaming box must go into the HDMI-In of your soundbar/receiver and the out of the soundbar/receiver must go to one of the HDMI-Ins of your TV.

If you use a soundbar, it must also support DTS-HD/X. The popular Sonos Arc does only support DTS but not DTS-HD/X. While it may be a great soundbar for streaming apps like Netflix and the like, I highly recommend going for something different which does support Dolby TrueHD and DTS:X.

I sold my Nvidia Shield the day that Xbox got the software update which enabled support for audio passthrough. Therefore, I don’t remember if audio passthrough must be specifically enabled on the Shield, but I know it has to be manually enabled on an Xbox. You can read how to do that here.

My Home Cinema Setup

I have perfected my home cinema setup, and it can direct play basically anything I throw at it. Here’s how it looks like.

• TV: LG OLED C1
• Soundbar: LG SN8YG
• Streaming Box: Xbox Series X

My Xbox is hooked up to an HDMI 2.1 switch which has two HDMI-Outs. One goes to the HDMI-In of the soundbar and the other one goes to an HDMI-In of the TV. The HDMI-Out of the soundbar goes to the eARC HDMI port of the TV. This port can act as an HDMI-In when the switch is outputting to the soundbar, and it can act as an audio-out (return channel) when the switch is outputting to a different HDMI-In of the TV directly.

Home Cinema Diagram (Icons by: https://icons8.com)

The blue and green lines on the left are the same HDMI cable connected to the HDMI eARC port of the TV.

The reason I’m doing it like this is because the HDMI passthrough of the soundbar only supports 4K @ 60 Hz fixed but both the TV and the Xbox support 4K 120 Hz VRR. So, when I’m playing games, I have the switch active on the TV. With this config, I can also direct play TrueHD content from Plex because the TV can pass that via eARC to the soundbar.

The Xbox has a very handy menu in Volume & audio output settings that tells you exactly which audio formats are supported with your current setup.

Supported HDMI formats with eARC (Xbox connected directly to TV)

When I want to watch something with DTS-HD/X audio, I just change the output on the switch to go to the soundbar. While I could also direct play Dolby TrueHD with this config, I’m losing an additional 60 Hz and VRR. I get the best of both worlds by using a switch and setting it to whatever mode I need it for the current job.

Supported HDMI formats with HDMI passthrough (Xbox connected to Soundbar HDMI-In)

I have a simplified setup of the one I described above in my bedroom. In my bedroom, I don’t have a HDMI switch. My Xbox Series S is connected to the HDMI-In of the soundbar and the HDMI-Out of the soundbar is connected to the HDMI eARC port of the TV.

Diagram for Simplified Setup (Icons by: https://icons8.com)

The blue and green lines on the right are the same HDMI cable connected to the HDMI ARC port of the TV.

In this set up, only the TV supports eARC but the soundbar does not. That means that I can’t direct play Dolby TrueHD via Plex for LG but other apps such as Netflix or live TV etc. will still send audio to the soundbar over ARC. However, Plex on Xbox is able to direct play Dolby TrueHD and DTS-HD/X since everything goes through the soundbar before it gets to the TV.

Here you can see that DTS-HD-MA 7.1 is easily direct played, even though it’s just a 3.0.2 soundbar (SN7CY).

Direct Play of DTS-HD MA

This is just a 1080p file but since video was never the issue in the first place, I have no issues direct playing any 4K HEVC HDR video with lossless audio either.

4K HDR HEVC DTS-HD MA 7.1 Direct Play

4K HDR HEVC Dolby TrueHD 7.1 Direct Play

If you have an Xbox, you can check if it’s sending the audio directly to the soundbar/receiver by pressing the Xbox Guide Button. You’ll see a PASSTHROUGH label when it’s active.

Xbox Audio Passthrough Label

When I play the same file on the Plex for LG app on the C1, the audio is transcoded because the TV doesn’t support DTS formats at all.

Direct Stream / Audio Transcode of DTS-HD MA 7.1

Xbox consoles also feature an Audio setup menu which lets you test/demo all supported audio formats. Of course, this will only let you select formats which are actually supported in your setup.

Audio setup in Xbox settings

Conclusion

In most cases, your Plex client not direct playing media is caused because your client/setup is incompatible with lossless audio and not because it can’t direct play the video you’re trying to stream. To fix it, you’ll need a soundbar or a receiver which supports decoding of lossless audio, and your TV needs to be able to pass through Dolby TrueHD and DTS-HD/X, or you’ll need to buy a streaming player like an Xbox or an Nvidia Shield which supports audio passthrough and hook it up through HDMI passthrough of your soundbar/receiver.

Audio passthrough and HDMI passthrough are two different things. Audio passthrough is a software setting on Xbox/Shield which allows the device to send the audio directly to the soundbar/receiver so that this device can decode and play the audio. HDMI passthrough means that the soundbar is capable of receiving audio and video streams (over the same HDMI cable), decode (play) the audio and pass the video stream to the TV over the HDMI-Out port of the soundbar.

Albeit they are very popular choices, an Apple TV 4K or the new Chromecast with Google TV both don’t support audio passthrough and won’t help you achieve the holy grail of direct playing everything. An Xbox might not seem like an obvious choice, but it really is a great Plex client, especially since the Xbox Series S is quite affordable.

Alternatively, if your video files include an AC3 or EAC3 audio track in addition to TrueHD or DTS-HD, you can also switch to that audio track to make the file direct play. Of course, you may be missing out on some of the audio detail, but the good thing is that even lossy Dolby Digital Plus supports Atmos. This is essentially what you’re getting when Netflix or other streaming services label content as Dolby Atmos. You’re getting lossy and not lossless.

Example of a Video which includes both TrueHD and AC3 audio tracks

I hope this helps clear things up and that it helps you to achieve direct play heaven as well.