how much network bandwidth is required?

[fpdave]

I have a recording server, and am playing back live tv to another pc.

This is over a power line based Devolo dLan which reports 120Mbps upstream
(from my recording server), so should be fine.

But I am getting bad stuttering.

Playback is fine for 10 seconds when it starts live replay, but it then deteriorates and stutters badly.

Windows is reporting 3.5-3.8MBytes/sec network transfer rate, which should only be about 24Mbps, so should be fine. If I try and copy a file at the same time it doesnt get much/any worse and the transfer rate goes up a bit.

CPU utilisation is 50% with the overlay renderer.

I'm using PVRX2 on vista and I've tried several different renderers and mpeg2 decoders.

[HarryH3]

Many other users have reported stuttering problems using powerline networking. By its design, TCP/IP allows packets to go missing if there are problems somewhere in the data path. If the receiver hasn't seen an expected packet within a given amount of time, or if a packet arrives damaged, then the receiver simply requests that the sender retransmit that packet (or packets). This process works wonderfully for downloading files, sending email, displaying web pages, etc. as the complete file is reassembled in the background before you ever know there were problems.

However, in video streaming it's obviously very important that ALL of the packets arrive and that they arrive in sequence and in a timely manner. Using a larger cache can help, as it gives the process time to gather missing or damaged packets before sending the stream on to the video renderer. If the data stream is dropping and/or damaging a lot of packets, then the packets may not be correct in the cache when they're called. Each time this happens, you see garbage on your screen...

Powerline networking is vulnerable to all sorts of interference from electrical motors, poorly designed power supplies, RF signals showing up on those nice, long, untwisted power wires (think antenna) running through your house, etc. That noise can mess up your data stream. Similar dropouts can happen with wireless networks, as they're subject to all kinds of RF interference from other networks, wireless phones, baby monitors and such that share the same spectrum.

Sometimes you get lucky with powerline or wireless networking and it just works. But any interference is going to degrade the video. So far, nothing beats a good old Cat5 or better Ethernet cable strung between the sender and receiver. It's the most reliable way to stream video.

[dslowik]

You might want to try running the DPC latency checker at http://www.thesycon.de/deu/latency_check.shtml to see if a driver might be stealing to much time from your CPU.

[fpdave]

Sorted (I hope).

on my server I altered the Recording Source LiveTV Quality (config|Capture Sources|Edit|Recording Source Settings|Live TV Quality), to NTSC 352x480/PAL 352x576, Constant, 2500kbits/sec. The quality seems OK, but its also reliable (for the last few days anyway).

Previously it was set at variable bit rate 4000-6000 kbits/sec!!

[morser]

This might help.

I upgraded my network from 100mb to 1000mb. I was streaming uncompressed video capture to gbpvr clients. If I understood perfmon correctly, during playback of a 1080i video file, my network bandwidth in use was 384mbps

[-stattik-]

You may want to tweak this setting in config.xml.

<ClientModeCachedReadSize>49152</ClientModeCachedReadSize>