My guess would be the SD card being the problem. SD cards aren’t that fast, even in best case scenarios and a raspi isn’t exactly a best case scenario. And besides, you’re probably sharing it with the OS. Try a USB HDD or at the very least a fast USB 3.0 stick.
(Also, Class 10 doesn’t say anything about read speed, only write speed that isn’t terribly fast either with 10MB/s. A UHS rating would give more indication about read speeds)
Direct play is scp the file to the pi and play from the class 10 sd card. LAN is gigabit.
My guess would be the SD card being the problem. SD cards aren’t that fast, even in best case scenarios and a raspi isn’t exactly a best case scenario. And besides, you’re probably sharing it with the OS. Try a USB HDD or at the very least a fast USB 3.0 stick.
(Also, Class 10 doesn’t say anything about read speed, only write speed that isn’t terribly fast either with 10MB/s. A UHS rating would give more indication about read speeds)