On Sun, 2008-02-24 at 11:29 +0000, Stroller wrote: > On 24 Feb 2008, at 11:01, Florian Philipp wrote: > > ... > > I noticed a very annoying behavior. I've got a headless server (Athlon > > 64 X2) which primarily acts as a personal video recorder using > > mencoder > > and at-daemon. ... > > > > ... My problem is: Neither of them can handle > > recording/playing video while there is any background activity. That > > means I have to stop the dnet-daemon and suspend any emerges on my > > laptop. If I don't, both mencoder and mplayer loose sync of audio and > > video and drops frames. > > ... > > Hi there, > > What capture card are you using to record TV? > > > I would expect most people these days to be receiving some kind of > digital signal - DVB-T using an aerial, DVB-S using a dish or DVB-C > via cable. Here in the UK, for example, it would be most common to > receive DVB-T "Freeview". > > Receiving a digital signal requires no encoding, practically no > processor resources, as the DVB signal is just mpeg, and the card is > simply dumping the stream to hard-disk. > > Are you playing back the video across the network? > What processor / RAM configurations do your PCs have? > What hard-drives? > What size are the videos (pixels) and what format (encoding, bitrate) > are they stored in on your hard-drive? > > I think you have to demonstrate that the problem is processor-bound. > My immediate thought upon reports of stuttering is to question disk > or network throughput. > > Stroller.
It's a PCI-card for analog TV (ordinary cable with about 20 channels). It doesn't output mpeg but raw video/audio so I have to encode it. I use h.264 (1 pass, 2 threads) and lame. The settings are tweaked to allow 25fps and a good overall quality. I could give you the settings but I don't think they're really important. The load is somewhere around 1.3 to 1.8. Of course I could tweak it to achieve 25fps even with dnet-client in the background but that would cost me quality and wouldn't fix my problem on the notebook. On my notebook, CPU-utilization is just around 50%. There is no apparent bottleneck on my setup. The 100MBit network is fast enough to transfer the files while playback is running even without caching. I'm decoding them on my notebook. If there were a bottleneck other than CPU-scheduling, it would hit me every time, not just when another process demands CPU-time.
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