While wireless G is technically a theoretical 54Mbps and yours says 48Mbps, actual data throughput is lower...I could get 25Mbps max. In the right conditions, a MINORITY of the time, you'll see no issues. But, if you have other wifi signals in range or someone uses a microwave or cordless phone...forget it.
Also, video is time sensitive...the packets must transfer in order. For file transfers, packets can be retransmitted and it doesn't affect anything, but with video, this results in noticeable artifacts. Wireless is crappy for time-sensitive tasks.
Wireless N may help, but even many suffer the same problem with G as packets are dropped and must be resent. Powerline hasn't worked for everyone, either, probably for the same reason.
What would I suggest if you want to transfer HD material? Ethernet...works every time. Or you can look into MoCA.