[Fennec]

For me, Kodi (NFS) works a lot better than Plex when it comes to local playback. Why is this?
Using a Synology NAS DS918+ and Nvidia Shield (wired).
I don't understand the differences in software well enough to know but I'm sure there's a simple answer. 

The performance disparity is especially noticeable when skipping through TV Shows/Movies. Kodi is instant whereas plex will present a spinning wheel or the episode will pixelate when skipping just 30 seconds ahead, or it may even take a minute or so to catch up when moving 20+ minutes ahead. Kodi is always instant. This seems to be an issue with transcoding and direct streaming as opposed to direct playing. Yet Kodi doesn't need to do any transcoding or direct streaming? I suppose because Kodi is not a server like Plex is? I don't know.

[PatK]

This question is a little like the differences between apples & oranges to some extent, both sweet, both attractive. In the past the two programs were much closer in operation but over the years this has spread to the point one would not be recognizable from the other. The location of the database where all of your media metadata is stored might answer some of the performance differences, Plex keeps the library on a media server, while Kodi keeps the library local. There are advantages to both set-ups but for home use nothing beats fast & local. I could talk about add-ons to the cows come home, both have them and in that respect, they are not what I expect from Kodi. There are extras that share meta-data & library between the programs,  but again I prefer to keep the software separate for less complexity and ease of maintenance. Given skin choices, and the sheer flexibility of the customization and the continuous effort by motivated developers we have in Kodi a world class program and a great community.

Chief differences would be the open sources and free to use software, and for some users, that is everything. But no one says you can't have both.

[Fennec]

The location of the database where all of your media metadata is stored might answer some of the performance differences, Plex keeps the library on a media server, while Kodi keeps the library local. 

Yep, I'm aware of this. Kodi stores the metadata on my Shield while Plex stores it on my Synology NAS. Maybe this is where I'm somewhat confused. Isn't metadata *mostly* things like cover art, backgrounds and the synopsis etc? I wouldn't expect this to cause a substantial difference in local playback between the two pieces of software.

And I still don't understand why Plex would need to transcode many different audio formats -- does Kodi need to do this? If we take the Nvidia Shield for example, it supports all of my media's audio formats and yet Plex still needs to transcode some of them. I was told else where that this is because I don't have the hardware (AVR) to direct play them. So wouldn't Kodi be faced with the same issue?

[PatK]

I wouldn't expect this to cause a substantial difference in local playback

Then again, it's a network thing... you must have access to the internet for the server to call home, not to mention that Kodi doesn't transcode and in that process is processor slices.

Plex would need to transcode

Transcoding allows for smaller file sizes for faster network transmission, but requires more processor slices on both ends. While standard gfx encodes are handled by most graphic engines in chip hardware these days which Kodi can take advantage of, using hardware decoding.

[Fennec]

 

Transcoding allows for smaller file sizes for faster network transmission, but requires more processor slices on both ends. While standard gfx encodes are handled by most graphic engines in chip hardware these days which Kodi can take advantage of, using hardware decoding.

To see if I'm understanding this correctly, by "both ends" requiring "more processor" power, you mean the server (my NAS) and client (my Shield), right? Kinda thought transcoding was handled entirely from the server (NAS). 

So Kodi would be using the hardware decoding of my Shield for local?

[PatK]

So Kodi would be using the hardware decoding of my Shield for local?

If Kodi is on the shield it will attempt to use the gfx hardware routines built into the shield, if that fails it will attempt to use the Nvidia Tegra K1-32 CPU (you should be able to check the differences in the settings, hardware accel vs software rendering), local storage would likely be a USB drive vs. network.