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| Choppy Live TV http://forums.linhes.org/viewtopic.php?f=15&t=18297 |
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| Author: | stinga [ Mon May 12, 2008 2:48 pm ] |
| Post subject: | Choppy Live TV |
G'day all, I have 3 DVB's and 1 pvr350. Recording and watching from all cards is fine. Watching live TV from pvr350 is OK but from the DVB cards it is not. It is like using VOIP where packets are being lost, I think the video is OK but the audio is choppy. (but that might be me noticing the audio more then the video) Watching live TV, pressing record and then watching the recording is fine, so it can't be the stream to disk that is the problem, it is getting the data off the disk. Any ideas what the issue might be? Memory seems OK. Code: root@mythtv:~# free total used free shared buffers cached Mem: 1032972 1019404 13568 0 3420 686772 -/+ buffers/cache: 329212 703760 Swap: 1959920 412288 1547632 vmstat 3 Shows anywhere from 70 to 90 id on both cards. In fact the output from vmstat is nearly identical when using each card type. I thought about IRQ's and I have a less then ideal situation on one of the DVB cards. Code: root@mythtv:~# cat /proc/interrupts CPU0 0: 797700235 IO-APIC-edge timer 4: 4 IO-APIC-edge serial 6: 3 IO-APIC-edge floppy 8: 1 IO-APIC-edge rtc 9: 0 IO-APIC-level acpi 12: 2380 IO-APIC-edge i8042 14: 4359117 IO-APIC-edge ide0 15: 72 IO-APIC-edge ide1 16: 90139524 IO-APIC-level eth0 17: 4774 IO-APIC-level libata 18: 261545513 IO-APIC-level ivtv0, Technisat/B2C2 FlexCop II/IIb/III Digital TV PCI Driver, nvidia 19: 3875605 IO-APIC-level EMU10K1 20: 46404472 IO-APIC-level Technisat/B2C2 FlexCop II/IIb/III Digital TV PCI Driver 21: 2108665 IO-APIC-level Technisat/B2C2 FlexCop II/IIb/III Digital TV PCI Driver NMI: 0 LOC: 797709712 ERR: 1 MIS: 0 but changing to another DVB card makes no difference. Code: root@mythtv:~# cat /proc/cpuinfo
processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 44 model name : AMD Sempron(tm) Processor 2600+ stepping : 2 cpu MHz : 1607.820 cache size : 128 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up pni lahf_lm ts ttp tm stc bogomips : 3216.66 I am thinking of building a new FE and moving ones of the cards to it, we can get HD over DVB-S but this FE/BE does not have enough grunt. Anu ideas on what the issue might be? |
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| Author: | cliffsjunk [ Tue May 13, 2008 5:14 pm ] |
| Post subject: | |
Your join date says you probably already know about XvMc and how much it helps if you have an Nvidia card although I am not sure it helps anything but Mpeg2 playback. That Sempron sounds a little weak if you are trying to play HD at all. Did I hear you say that you can watch a recording while it is recording, but you cannot watch live TV which should be the same? These should be the same except for maybe squeezing it all in one set of buffers when playing live, which should make live better if anything. Do you have a different recording profile for live vs. recorded? You may swap the cards around into different slots as 5 slot motherboards share an IRQ, usually between slots 4 and 5. If you set the BIOS to "Pnp OS = NO" it will assign irq's and print them out just before boot up. I used to use this to move cards off of shared IRQ's as a first pass hardware setup trick before installing an OS. Are you running a PCI or an AGP fx5200? My understanding is that AGP (e.g. AGP 8x) is better than even PCIx. On a PATA Athlon 1400 system (pvr-350) I get over 45 mbytes a second from dd. Code: dd bs=1M if=/dev/hda of=/dev/null count=1000
should take less than 30 seconds to run for a test. You may use hdparm to try "unmask IRQ" for your hard drive, but backup or research the data corrupting possibilities first. Good luck, Cliff |
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| Author: | goofnrox [ Wed May 14, 2008 7:30 am ] |
| Post subject: | |
I have the exact same problem. Watching live TV with my Air2PC is very choppy, but starting a recording, and watching that recording is fine. I also have a PVR150 that works as it should for live TV. Myth is supposed to be acting the same for live TV and recordings, but it seems it is not, and I have not been able to find a fix for it. Good luck and post up if you find a fix. |
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| Author: | stinga [ Wed May 14, 2008 8:52 am ] |
| Post subject: | |
G'day, Yes, I know about XvMc and nvidia cards. Not doing HD at the moment, but plan to soon and then a new FE will be needed. Yes, I can watch a recording while recording it and the play back is fine. Since DVB is an mpeg2 stream and it just gets dumped to disk there is nothing settable in the "Live TV" profile for those devices. That could be a factor, because I can set the pvr350. I don't think swapping cards is going to make much difference, since it happens on all DVB cards, and 2 of the 3 are on their onwn IRQ. AGP fx5200 Code: 01:00.0 VGA compatible controller: nVidia Corporation NV34 [GeForce FX 5200] (rev a1) (prog-if 00 [VGA]) Subsystem: Micro-Star International Co., Ltd. Unknown device 9073 Flags: bus master, 66MHz, medium devsel, latency 248, IRQ 18 Memory at fd000000 (32-bit, non-prefetchable) [size=16M] Memory at d8000000 (32-bit, prefetchable) [size=128M] [virtual] Expansion ROM at fe9e0000 [disabled] [size=128K] Capabilities: [60] Power Management version 2 Capabilities: [44] AGP version 3.0 Code: root@mythtv:~# dd bs=1M if=/dev/hda of=/dev/null count=1000
1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 18.3275 seconds, 57.2 MB/s Maybe solved!! There is a setting in the FE setup called "extra Audio buffering", I have set this and the problem seems to have gone away. I have not done extensive watching though to see if it really has gone.[/b] |
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| Author: | goofnrox [ Wed May 14, 2008 10:47 am ] |
| Post subject: | |
Maybe solved!! There is a setting in the FE setup called "extra Audio buffering", I have set this and the problem seems to have gone away. I have not done extensive watching though to see if it really has gone.[/b][/quote] This seems to have worked on mine also! Both HD and SD ATSC channels play fine now. Suiteness. |
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