Cant fast forward Videos in UMS 9.3.1

[mik_s]

No its not in the UMS program but on your renderer. you should see it alongside all your files.
If its not there then check to make sure that "Show the #-TRANSCODE-# folder" option is checked in the navigation settings.

[Nadahar]

UMS doesn't support transcoding to MP4. That said, the duration (in bytes, not seconds) would still be unknown so I don't quite see how it would solve anything.

In short, seeking while transcoding works on some renderers but not on others. The fundamental problem is that some use byte-based positioning (by number x from the start of the file) and some use time-based positioning. When transcoding, the duration in bytes in undefined, there's no way to know that until you have transcoded the whole file (aka played through it). The duration in time is known since it is the same as the duration of the source file. This means that renderers that use time-based positioning does support seeking while transcoding, but those that only accepts byte-based positioning doesn't.

That said, it's not quite that simple, as there are multiple details I left out, that can impact what the renderer supports and not. UMS doesn't handle all of these details properly, so there are probably some renderers where it could work had UMS done it correctly where it's not available. But, those that only support byte-based positioning regardless of if UMS had done all it should correctly, ultimately cannot seek when transcoding. There's simply no way to translate a byte-offset into a specific position when the data is being generated on-the-fly. The data that has already been transcoded isn't stored either, so UMS doesn't even know where it is byte-wise at any given time. When files aren't being transcoded, the situation is completely different, because the file is available on disk and the size is known, so jumping to any specific position in the source file is easy.

[mik_s]

A standard mp4 or mkv using H264 video and AAC audio should work just fine.

you only really need to do the "no transcoding" for files you think should be streamed which are getting transcoded to get an idea if UMS is making the right decision, and then you can tweak the config if it gets it wrong.

[mik_s]

Do any of those play on yours when using no transcoding?
I don't know anything about Roku but looking at the available configs there must be different versions which have more support. Also check for a firmware update see if that improves it.