Testing network performance

[Karamano]

(23rd Dec, 2012 10:18 PM)Enigmach Wrote:  Just my two cents since I've experienced similar problems before changing my setup. (My previous setup was my media on the pc connected through wifi with an NFS server, and my RPi cabled with no DTS receiver. This caused a lot of stutter on most media, even with overclocking.)

If I were you I would look into a different class of SD-card. I recently switched from a new Kingston Class 4 card to a Class 10 card and everything is incredibly smooth. My reasoning behind this, is that the streams that stutter in your case have a video bitrate above 4000 kbps and the ones that don't have bitrates below that. I'm not sure on how the Pi uses the networked files, but it seems as though the minimum write speed of the SD card of 4 MB/s could be the bottleneck which it was in my case. So if you have another card lying around, or willing to pay €9,- or something you could try this out.

Just as a note: files from USB worked better in my previous setup as well.

A few tests I did on the matter of the sd card:

1) Loaded problematic video files onto sd card and all played smooth.
Further more, a 20min clip took less than 14min to transfer over the network onto the sd card, which I assume means there is hypothetically enough network juice to keep up with the video, just the Pi or XBMC can't process the file successfully on the fly.

2) Executed "sudo hdparm -tT /dev/mmcblk0" test and got:

Terminal

Timing cached reads: 162 MB in 2.00 seconds = 80.80 MB/sec
Timing buffered disk reads: 58 MB in 3.06 seconds = 18.96 MB/sec

So I think sd card is up to speed, if I'm not mistaken.