Recording HD to a network drive

[jonm]

I'll certainly give it a try - thanks.

[jonm]

Lol, if you can copy 9GB over 10 minutes, wonder why it's struggling to copy the same over the span of an hour. What are the specs of your PC and what's your set-up like?

The media PC is pretty new, 2.6Ghz core2duo with 2Gb RAM, and the server at the other end is a 2.4Ghz P4 running Fedora.

Network performance doesn't seem to be an issue, as evidenced by the copying of a 9Gb recording in 10 mins, so I really don't know what's going on.

I'm wondering what config settings in GBPVR I can tweak that would affect this?

[jonm]

Changed the Vista network throttling settings, and it's made no difference.

I'm just trying recording HD to the server now, and I can see from the server that it's receiving about 1460Kb/sec over the network, but also transmitting about 500Kb/sec. That suggests to me that there's a lot of network overhead going on, presumably very small packets? [Or am I talking rubbish?]


nmon Linux9g Hostname=lord Refresh= 2secs 14:53.50
Network I/O
I/F Name Recv=KB/s Trans=KB/s packin packout insize outsize Peak->Recv Trans
eth0 1472.5 511.6 4803.5 4804.5 313.9 109.0 1481.7 514.8


Based on an hour of HD being around 9Gb, that network rate needs to be more like 2600kb/sec by my rough calculations.

[ilovejedd]

Just did some calculations. 9GB (albeit, 1 hour HD recording is probably closer to 8GB than 9GB) over 10 minutes is 15.36 MB/s. Maximum bitrate of OTA HD is 19mb/s (at least in the US, dunno what it is in UK), around 2.375 MB/s. There seems to be something weird going on, just dunno if it's Vista, Fedora or something else. Do you have a spare Windows PC which you might be able to dump recordings to in lieu of the Fedora server?

Do you happen to have QoS enabled on the router?

[jonm]

Do you have a spare Windows PC which you might be able to dump recordings to in lieu of the Fedora server?

Do you happen to have QoS enabled on the router?

Hi, thanks for the suggestions. I already tried recording to another Windows PC, same symptoms - although it's not quite as easy to see the exact network throughput, but I tried playing the recorded file and it was corrupted just like the ones recorded to the Fedora server are.

As for QoS - there is no router, there's just a Gbit switch between the two. I've tried two different switches - a 3Com and a Netgear - with no effect.

[ilovejedd]

It seems to point the problem is with the Vista server. What specific version of Windows are the other PC's running? Can you try installing GB-PVR on those and transferring the TV tuner temporarily?

[jonm]

I guess I could try, I have a spare-ish PC running XP that I could install it on.

(I really don't want to be running XP on my media PC though, so I'll be dismayed if that works, but at least it would point the finger at Vista as you say)

[mvallevand]

I don't think it is Vista so much as the efficiency of using a Windows share. I read a message from sub recently that said that ts files are written as they are read from the capture card so all those 188 byte writes are going to be intensive to a network. If you add a mux on top of it there is just that much more chance for problem.

You can't possibly compare a write with a read, since reads will be blocked.

Martin

[jonm]

Interesting... thanks. Why 188 bytes? I don't suppose you can point me to that message?

[sub]

Because thats what size transport stream packets are. GB-PVR doesnt flush them to disk when writing though, so disk buffering normally wites them in bigger chunks every so often.