Server: Latest Plex on Ubuntu LTS
Client: Android 11 and Windows 10
Whenever I download any video from my Plex server on the local network, the download speed is extremely slow if I select a lower video quality to download. However, if I download original quality, the speed is blazing fast.
I have tried this even on a PC which has gigabit Ethernet to the PMS.
The download speed when is 100 Mbps or less when I download the lower quality.
Before you can download a lower quality version of the media, it needs to be transcoded by your server to create that version. Downloading the original quality all the server needs to do is send a copy of the original file which compared to transcoding has practically no CPU load required.
-Shark2k
But is transcoder really that slow? I mean I use an NVME for OS and Plex Metadata. And I have a 10th gen i3. I expected better.
It’s really dependent on your CPU if you are doing software transcoding or GPU if doing hardware transcoding. Then there are other factors that will determine how fast it’s going to be done such as what you have the transcoder quality option set to in settings for your server. Another factor is what the quality of the source file is (720p, 1080p, 4k, any of those last 2 as full Blu-ray remuxes meaning they have the original bitrate from the Blu-ray, no prior transcoding) and then what quality you are going down too. Also, if you have other activity going on on your server that will have an impact.
Of course there is also the fact that it depends on how Plex handles doing the transcode and sending the data to the client. I believe Plex creates chunks and sends those, so depending on the size of the chunks, you might be getting “full” speed from those because they are small enough that they don’t get up to the speeds you see with original quality.
-Shark2k
Yes; it really is that slow! You didn’t specify the quality settings you were using but that you were getting around 100Mbps transfer speed so I can’t speak to details but that sounds like your transcode is going quite fast.
The only kind of “chucks” going on here is in the bowels of the transcoder. libavformat (the part of the transcoder writing the output) writes parts of the file in small chunks (the elements within a cluster in an MKV file). Everything else is streamed to the client as soon as it’s available.
Thanks for verifying what I thought about the transcoding being slow.
Also, thanks for the response to my second part.
I think what I might have been thinking of/referring to is how I believe I understood sync to work (and downloads may still use the same concept) which was to have many different smaller sized files that added up to the full media and Plex would play those back seamlessly. If that is true, that is actually what I was referring to and chunks probably wasn’t the best way to describe that.
-Shark2k
The original file was H264 and its bitrate was about 15 Mbps. I tried to download medium and low quality on PC.
I only recently discovered Downloads on Plex, and it seriously needs some working. Maybe give an option to transcode first then download?
It doesnt matter if you transcode first and download after, you will spend the same amount of time. Download works as intended, if you reduce quality the file is transcoded as quickly as your hardware allows.
If you believe the transcode is slow, get better hardware - Switch to hardware accelerated transcoding, etc. Its on you.
downloading original quality from your server is just copying (remuxing) your movie file to your client device. no transcode is happening in between the server and client.
downloading a lower quality on the other hand is the original movie file in your Plex server is being transcoded (being created first because you don’t have that file in your server) before transferring the lower quality version file in the client. transcoding takes time and also depends on PC CPU.
Another thing, It don’t matter whether you have GIGABIT internet/network switch for LAN in transcoding because your computer (Plex server) dictates the duration of your transcode. If you got shityy outdated PC/Nas server, it would take more time than those PC with powerful CPUs.
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