Hi, i have a 1080p / bluray / mkv files that is usually about 20gb+ in size, - is there a reason on either the ipad or the apple tv 4 app - that it usually stops and say network connection to server is slow - when having Direct Stream and Direct Play turned on - but with Direct Stream turned off - it plays fine.
One possible answer is that the file has parts where the bitrate jumps a lot and so your network can’t transfer the file fast enough. I’ve seen cases where the bitrate can increase by 10 times. For example, say you have a file that has an average bitrate of 20 Mbps, at one scene, the bitrate jumps to 100 Mbps. If your network isn’t capable of handling the 200 Mbps stream, you get that message. When you turn of direct stream, PMs is most likely transcoding the file. PMS will cut off the spikes so you won’t have the 200 Mbps jump.
I’ve noticed that transcoding usually uses much smaller buffers than Direct Play too, so maybe that could be a factor.
I’ve noticed something similar as well. When I select the “Original” quality and Direct Play is used, it buffers a lot. However, if I select a another quality (to force the transcode) the file will stream without any buffering. What’s odd to me is that this will happen even when the difference between the Original quality and selected quality is small (Example: original quality is 4.5 Mbps and the selected quality is 4.0 Mbps).
If anyone has any ideas, I’m all ears! 
Maybe your network connection is only capable of transferring at 4.2 Mbps.
The original bitrate is also an average, so there may be large peaks and valleys and the peaks are causing the buffering. When PMS transcoded, it flattens out the peaks.
That’s a good point about the fluctuation of the bitrate in the non-transcoded stream. If I disable Direct Play and Direct Stream, will that force Plex to transcode everything?
Yes, that will force transcode of everything.
