[mythtv-users] Bug in "Watch Recordings" ?
Steven Cruysberghs
steven.cruysberghs at pi.be
Thu May 13 08:19:02 EDT 2004
Short answer to long mail :
if you are using .14 version this is probably the bug where the preview
video from the "watch recordings" screen keeps playing in the background.
This has been fixed in CVS.
> Sorry for the long email, but there was a lot to say!! (Get comfortable)
>
> I think I found a bug in MythTV, specifically in "Watch Recordings".
>
> First let me explain my setup...
>
> I have my master backend in my living room, with 2 CTV receivers hooked
> up. The ringbuffer, and all recordings are stored on an NFS mounted data
> server connected over cat 5. I also have a slave frontend in my bedroom,
> coonected to the master backend over my 802.11G (54Mbps wireless). The
> slave has no tuners defined, so to watch tv, I use an unused tuner on
> the master backend, streamed wirelessly.
>
> On the master backed I have little to no problems. However, I have been
> noticing problems the slave in the bedroom. The video "stutters" like
> there is not enough bandwidth on the wireless link to handle the stream.
>
> It finally got to the point where I started troubleshooting. First off,
> I KNOW the pipe is big enough for the stream, as I can watch live tv on
> my laptop (802.11b - 11Mbps).
>
> What I discovered was, if I reboot both boxes, and go into live TV on
> the slave, everything works fine. For hours I can watch TV with no
> hiccups. Then I go into "Watch Recordings" and it plays fine for a few
> minutes, then starts stuttering. Now keep in mind, the recordings are
> physically on my data server, NFS mounted on the master backend,
> streamed over the wireless. At first I thought there was too much
> latency in the network, but here is where it gets odd.
>
> If I exit out of the recording, the network traffic does not die. Even
> after 20 minutes of sitting at the main menu, the activity lights are
> going nuts. I do some packet sniffing, and see myth traffic (port 6543)
> going back to the master backend. Furthermore, I see a ton of NFS
> traffic going between the master backend, and the data server. If I kill
> the frontend and both boxes, the traffic stops. Next I tried it the same
> thing on the master backend. If start watching a recording (stored on
> the dataserver). The hub lights up, as expected. I exit out, and the
> lights keep going! A tcpdump shows that it's all NFS traffic (the port
> 6543) traffic would not hit the wire, as the masterbackend is also the
> frontend). If I kill the frontend, the traffic stops.
>
> It seems like a few minutes into watching recordings, a huge amount of
> "extra" packets are being generated, and don't stop, even if sitting at
> the menu. There is no video stuttering on the master backend, presumably
> because the 100Mbps line can handle the "extra" traffic. Unfortunately,
> the wireless link can not. I did some bandwidth tests on that link, and
> consistantly get 1.2Mbps through - more that plenty, so this additional
> traffic must be a lot.
>
> Now, here are some answers to questions I KNOW are coming:
>
> 1. My recordings are being recorded at the exact same bitrate as live TV
>
> 2. I am not transcoding the files afterwards
>
> 3. When I exit the recording, I am not sitting at the "preview" screen,
> so the traffic is not coming from the thumbnail preview stream.
>
> And here is a snip of the tcpdumps I took:
>
> Sitting at the main menu, this is the traffic between the slave and the
> master backend:
>
> 22:34:13.183065 10.2.100.5.6543 > 10.2.100.7.32780: . 3808:5256(1448)
> ack 1 win 5792 <nop,nop,timestamp 107393 90608> (DF)
> 0x0000 4500 05dc 562c 4000 4006 02e0 0a02 6405 E...V, at .@.....d.
> 0x0010 0a02 6407 198f 800c 2c92 1d3b 27e7 addc ..d.....,..;'...
> 0x0020 8010 16a0 e61e 0000 0101 080a 0001 a381 ................
> 0x0030 0001 61f0 3282 b9ae b962 19d5 4e31 3de0 ..a.2....b..N1=.
> 0x0040 6300 1ae2 0810 e453 88c8 72ea b870 8c23 c......S..r..p.#
> 0x0050 f953 .S
> 22:34:13.183403 10.2.100.5.6543 > 10.2.100.7.32780: . 5256:6704(1448)
> ack 1 win 5792 <nop,nop,timestamp 107393 90608> (DF)
> 0x0000 4500 05dc 562d 4000 4006 02df 0a02 6405 E...V- at .@.....d.
> 0x0010 0a02 6407 198f 800c 2c92 22e3 27e7 addc ..d.....,.".'...
> 0x0020 8010 16a0 0e2d 0000 0101 080a 0001 a381 .....-..........
> 0x0030 0001 61f0 731e 06af 1061 8441 b931 17dd ..a.s....a.A.1..
> 0x0040 39a8 3b05 e827 0f03 626c 03ae 1f07 2c8b 9.;..'..bl....,.
> 0x0050 779d w.
> 22:34:13.183424 10.2.100.7.32780 > 10.2.100.5.6543: . ack 6704 win 63712
> <nop,nop,timestamp 90609 107393> (DF)
> 0x0000 4500 0034 103d 4000 4006 4e77 0a02 6407 E..4.=@. at .Nw..d.
> 0x0010 0a02 6405 800c 198f 27e7 addc 2c92 288b ..d.....'...,.(.
> 0x0020 8010 f8e0 d7da 0000 0101 080a 0001 61f1 ..............a.
> 0x0030 0001 a381 ....
> 22:34:13.183894 10.2.100.5.6543 > 10.2.100.7.32780: . 6704:8152(1448)
> ack 1 win 5792 <nop,nop,timestamp 107393 90608> (DF)
> 0x0000 4500 05dc 562e 4000 4006 02de 0a02 6405 E...V. at .@.....d.
> 0x0010 0a02 6407 198f 800c 2c92 288b 27e7 addc ..d.....,.(.'...
> 0x0020 8010 16a0 12f7 0000 0101 080a 0001 a381 ................
> 0x0030 0001 61f0 0018 b365 0b38 78ba 3b0e 5054 ..a....e.8x.;.PT
> 0x0040 fe87 09b6 164e 1dc3 cf9c 098b d803 d967 .....N.........g
> 0x0050 600e `.
> 22:34:13.185640 10.2.100.5.6543 > 10.2.100.7.32780: . 8152:9600(1448)
> ack 1 win 5792 <nop,nop,timestamp 107393 90609> (DF)
> 0x0000 4500 05dc 562f 4000 4006 02dd 0a02 6405 E...V/@. at .....d.
> 0x0010 0a02 6407 198f 800c 2c92 2e33 27e7 addc ..d.....,..3'...
> 0x0020 8010 16a0 a8ac 0000 0101 080a 0001 a381 ................
> 0x0030 0001 61f1 4918 5ec1 8bff e850 6871 e9b3 ..a.I.^....Phq..
> 0x0040 2810 62fa 530c ce22 d115 91ae 0000 0113 (.b.S.."........
> 0x0050 1224 .$
> 22:34:13.185657 10.2.100.7.32780 > 10.2.100.5.6543: . ack 9600 win 63712
> <nop,nop,timestamp 90609 107393> (DF)
> 0x0000 4500 0034 103e 4000 4006 4e76 0a02 6407 E..4.>@. at .Nv..d.
> 0x0010 0a02 6405 800c 198f 27e7 addc 2c92 33db ..d.....'...,.3.
> 0x0020 8010 f8e0 cc8a 0000 0101 080a 0001 61f1 ..............a.
> 0x0030 0001 a381 ....
>
> And here is a snip of the traffic between the master backend and the NFS
> data server:
>
>
> --
> ×·.¸¸.·´¨) ¸.·´ ¸.·´¨) O Jason Donahue
> (_¸.·´ (¸.·´¸.·× O jdonahue at timekiller.org
> (_¸.·´ O http://www.timekiller.org
>
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