I am wondering I created from plex web interface optimized versions for Mobile, TV and Original Quality and am noticing that the files are in some cases larger than the original files that I had uploaded to the server.
You’re using a narrow definition of “optimized” to mean efficiency in transmission. Optimized also means changed in form to better suit the playback device. That can mean video transcoded from more efficient formats to less computationally complex ones due to the direct play limitations of the client device, or to allow display of subtitles that are in a format the client can’t play natively.
When you ask for a file to be in “original” quality but also meet the requirements of a less-powerful playback device, the results will be larger because the transcoding needs to encode at a higher bitrate to maintain as much quality as possible despite the impact to quality that will occur from generational loss between two lossy codecs and the compression artifacts of the source codec combined with different artifacts of a destination codec.
Something to also be aware of is that, by default, Plex will “optimize” the media using H.264 for encoding. This alone can result in larger output file sizes if the source media was encoded using H.265 (aka, HEVC).
There’s a setting in your server’s transcoding settings to enable HEVC encoding; once enabled, you can further enable HEVC for optimization as well.
Need to make sure you’re on a recent Plex Media Server version. The settings are under the checkbox for hardware-acceleration for encoding. See pic here:
Hmmm. It’s an Apollo Lake processor, so I would think that would be fine for this. is your iGPU actually listed in the “Hardware Transcoding Device” menu?
Oh, man, I know! I had a double-take at that. When I saw that the DS418play was based on an Apollo Lake processor, I thought surely it supported HEVC encoding.
