Re: [mythtv-users]Tips for fixing prebuffering pause and WriteAudio: buffer underrun
I seem to have all of my install mistakes corrected, except for one. When I play recorded content all is well. But when I play live TV, I get many *prebuffering* *pause* messages, and an occasional WriteAudio: buffer underrun. The video stutters during the *prebuffering* messages. Did u compile with opengl-vsync on? Once that disabled, playback is fine on my machine... Regards. Tj ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users]Tips for fixing prebuffering pause and WriteAudio: buffer underrun
On Mar 31, 2005, at 8:04 AM, Tj NG wrote: I seem to have all of my install mistakes corrected, except for one. When I play recorded content all is well. But when I play live TV, I get many *prebuffering* *pause* messages, and an occasional WriteAudio: buffer underrun. The video stutters during the *prebuffering* messages. Did u compile with opengl-vsync on? Once that disabled, playback is fine on my machine... Regards. Tj Sadly, no. Always looking for the easy fix. I turned on full logging on the backend and the frontend, but I'll need to do some homework before I can total sense of it. It does look like the audio buffer is constantly low, but until I look into what code is writing what messages, I won't be able to decode what is happening. Thinking about this, I came up with what would be a cool debugging tool. It would be slick if there were dummy sources/sinks, that could be plugged into myth, and could be used to stress test the various parts of the system. So there would be a module that acted like a frontend, and tried to stream data from the backend at a rate that was stepped up until the backend couldn't keep up, and then printed statistics. Or a simplified backend that was capable of sending a simple stream (something like gears) at a high rate and logged stats about the requests from the frontend. Maybe this functionality exists, dunno. I do know if I was smarter, I would write it. I don't know if my problem right now is a slow backend, frontend, or network. I assume it is not the network, I'm using 100Mbps with a switch, and I tried copying files over NFS from the backend to the frontends /dev/null (frontend is diskless, nowhere else to write it that wouldn't interfere with the network), and noted a fairly decent throughput. Still on my list of things to try is use OSS instead of ALSA. Others have suggested ALSA may be the culprit, and they may be right, but I have a feeling it isn't. The problem is usually worse when entering live tv mode, and then smooths out, and then occasionally appears now and then. To me it seems like a borderline bandwidth issue somewhere. I think I'll try bumping down my bitrate. I did order parts from Monarch to build a new backend. I'm hoping to use these parts to try and troubleshoot this. If they ever ship. But thanks for the suggestion. -Michael ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users]Tips for fixing prebuffering pause and WriteAudio: buffer underrun
Michael Carland wrote: Still on my list of things to try is use OSS instead of ALSA. Others have suggested ALSA may be the culprit, and they may be right, but I have a feeling it isn't. The problem is usually worse when entering live tv mode, and then smooths out, and then occasionally appears now and then. To me it seems like a borderline bandwidth issue somewhere. I think I'll try bumping down my bitrate. I did order parts from Monarch to build a new backend. I'm hoping to use these parts to try and troubleshoot this. If they ever ship. But thanks for the suggestion. Sorry couldn't be much help. :) FWIW, I have no problems with ALSA (I am using 1.0.8).. Regarrds, Tj ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users]Tips for fixing prebuffering pause and WriteAudio: buffer underrun
On Mar 31, 2005, at 8:12 PM, Tj wrote: Michael Carland wrote: Still on my list of things to try is use OSS instead of ALSA. Others have suggested ALSA may be the culprit, and Sorry couldn't be much help. :) FWIW, I have no problems with ALSA (I am using 1.0.8).. Had high hopes there for a moment! Thought I was on ALSA 1.0.6, but I really have 1.0.8. Been reading too many posts tonight I guess. Thanks again. -Michael ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Tips for fixing prebuffering pause and WriteAudio: buffer underrun
--- Matthew Phillips [EMAIL PROTECTED] wrote: On 28/03/2005, at 9:15 AM, Michael Carland wrote: I seem to have all of my install mistakes corrected, except for one. When I play recorded content all is well. But when I play live TV, I get many prebuffering pause messages, and an occasional WriteAudio: buffer underrun. The video stutters during the prebuffering messages. Hi Michael, I had a very similar problem which cropped up after switching to ALSA output. After a long saga of list-trawling, it turned out to be an error with an uninitialised variable in Myth's ALSA audio module (I so wish C++ would regard this sort of thing as an error). After grabbing a patch from CVS and rebuilding, all is fixed. The patch against 0.17 is attached. Since we have the same frontend hw, I could look into making the (RPM) binaries available if there's somewhere to drop them. Matthew. Thanks for the patch. At first, I thought it worked. When I started live tv, 4 pauses and one underrun where logged, but then it was looking good. That lasted about a minute, and then it was back to the stuttering. It's a little confusing, it does not happen recording a program, and it does not happen when playing a recording, so it's not easy to pin on the frontend or backend. May I ask what kind of tuner card you are using? -Michael __ Do you Yahoo!? Yahoo! Mail - Easier than ever with enhanced search. Learn more. http://info.mail.yahoo.com/mail_250 ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Tips for fixing prebuffering pause and WriteAudio: buffer underrun
On 28/03/2005, at 11:22 PM, Michael Carland wrote: --- Matthew Phillips [EMAIL PROTECTED] wrote: On 28/03/2005, at 9:15 AM, Michael Carland wrote: I seem to have all of my install mistakes corrected, except for one. When I play recorded content all is well. But when I play live TV, I get many prebuffering pause messages, and an occasional WriteAudio: buffer underrun. The video stutters during the prebuffering messages. Hi Michael, I had a very similar problem which cropped up after switching to ALSA output. After a long saga of list-trawling, it turned out to be an error with an uninitialised variable in Myth's ALSA audio module (I so wish C++ would regard this sort of thing as an error). After grabbing a patch from CVS and rebuilding, all is fixed. The patch against 0.17 is attached. Since we have the same frontend hw, I could look into making the (RPM) binaries available if there's somewhere to drop them. Matthew. Thanks for the patch. At first, I thought it worked. When I started live tv, 4 pauses and one underrun where logged, but then it was looking good. That lasted about a minute, and then it was back to the stuttering. It's a little confusing, it does not happen recording a program, and it does not happen when playing a recording, so it's not easy to pin on the frontend or backend. That's very odd. My impression is that live TV mode is really the same as watching a recording as it's laid down (with the added feature of the buffer being limited and circular). So the fact that you get the problem only with live TV is unexpected - I was getting it regardless of mode. I also found that FF/RW a few times would re-sync until the next time I hit pause/unpause or a signal glitch threw it off. May I ask what kind of tuner card you are using? I'm using a VisionPlus VisionDTV DVB-T PCI card. Matthew. ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
[mythtv-users] Tips for fixing prebuffering pause and WriteAudio: buffer underrun
I seem to have all of my install mistakes corrected, except for one. When I play recorded content all is well. But when I play live TV, I get many prebuffering pause messages, and an occasional WriteAudio: buffer underrun. The video stutters during the prebuffering messages. I done some googling, and tried a few things, but have not been able to get around this. I am looking for tips on how to find the source of the problem. I have tried vmstat on both the frontend and the backend, and don't see anything that stands out. No swapping, plenty of memory, at least 20% idle cpu on both ends. I have the Extra audio buffering checked. I tried the Aggresive Soundcard Buffering, but it didn't help, so I turned it back off. I am using ALSA on the frontend, and other than the stutters, it sounds fine. Myth 0.17 The backend is a 400MHz K6-3, 2.6.10 kernel, PVR-500MCE, ivtv 0.3.2p. The frontend is an Epia M10K, 2.6.10 kernel, X.org 6.8.2 with XvMC enabled (and appears to be working from the logs). Output of frontend during live tv: 2005-03-27 17:17:34.691 Using protocol version 14 2005-03-27 17:17:37.867 Opening audio device 'default'. Using XvMC version: 1.0 XvMC found and using VLD surface 2005-03-27 17:17:37.958 Using XV port 64 Fulfilled via DRI at 5898240 Fulfilled via DRI at 6428192 Fulfilled via DRI at 6958144 Fulfilled via DRI at 7488096 Fulfilled via DRI at 8018048 Fulfilled via DRI at 8548000 Fulfilled via DRI at 9077952 Fulfilled via DRI at 9607904 Fulfilled via DRI at 10137856 2005-03-27 17:17:38.629 Using realtime priority. 2005-03-27 17:17:38.647 Changing from None to WatchingLiveTV 2005-03-27 17:17:38.657 Video timing method: DRM Freed 0 (pool 0) Freed 10491168 (pool 2) Fulfilled via DRI at 10491168 2005-03-27 17:17:47.315 prebuffering pause 2005-03-27 17:17:57.877 prebuffering pause 2005-03-27 17:17:58.256 prebuffering pause 2005-03-27 17:17:58.573 prebuffering pause 2005-03-27 17:17:58.889 prebuffering pause 2005-03-27 17:17:59.305 prebuffering pause 2005-03-27 17:17:59.622 prebuffering pause 2005-03-27 17:17:59.938 prebuffering pause 2005-03-27 17:18:00.255 prebuffering pause 2005-03-27 17:18:00.571 prebuffering pause 2005-03-27 17:18:00.887 prebuffering pause 2005-03-27 17:18:00.888 WriteAudio: buffer underrun Nothing special in the backend log: 2005-03-27 17:17:33.213 adding: myth as a client (events: 0) 2005-03-27 17:17:33.221 adding: myth as a remote ringbuffer 2005-03-27 17:17:33.236 Changing from None to WatchingLiveTV 2005-03-27 17:21:48.355 Changing from WatchingLiveTV to None vmstat on backend during live tv (ok, bo 0 may be odd, but I didn't see that before): procs ---memory-- ---swap-- -io --system-- cpu r b swpd free buff cache si sobibo incs us sy id wa 1 0 0 556680 15192 12833600 0 604 4490 4210 4 38 58 0 0 0 0 556104 15192 12886000 0 544 4443 4541 5 33 62 0 0 0 0 28 15192 12948000 0 640 4113 4917 3 28 69 0 0 0 0 554952 15192 13005200 0 620 4106 4838 3 28 69 0 0 0 0 554312 15192 13070000 0 0 4002 5313 2 26 72 0 0 0 0 553608 15192 13146000 0 668 3937 5112 2 26 72 0 0 0 0 552840 15192 13218800 0 828 4068 4532 4 34 62 0 And vmstat on frontend: procs ---memory-- ---swap-- -io --system-- cpu r b swpd free buff cache si sobibo incs us sy id wa 1 0 0 164028 0 16814400 0 0 1754 2035 23 21 56 0 2 0 0 164028 0 16814400 0 0 2406 2590 24 23 54 0 0 0 0 163900 0 16814400 0 0 2553 1628 40 49 11 0 0 0 0 163900 0 16814400 0 0 2342 1973 33 45 22 0 1 0 0 163900 0 16814400 0 0 3748 2761 39 46 14 0 0 0 0 163900 0 16814400 0 0 4291 3595 32 42 26 0 Any tips for further figuring this out? One thing I read was to turn off XvMC, but will that work on an cle266 without the deinterlacing (Bob)? Thanks, -Michael __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] Tips for fixing prebuffering pause and WriteAudio: buffer underrun
On 28/03/2005, at 9:15 AM, Michael Carland wrote: I seem to have all of my install mistakes corrected, except for one. When I play recorded content all is well. But when I play live TV, I get many prebuffering pause messages, and an occasional WriteAudio: buffer underrun. The video stutters during the prebuffering messages. I done some googling, and tried a few things, but have not been able to get around this. I am looking for tips on how to find the source of the problem. I have tried vmstat on both the frontend and the backend, and don't see anything that stands out. No swapping, plenty of memory, at least 20% idle cpu on both ends. I have the Extra audio buffering checked. I tried the Aggresive Soundcard Buffering, but it didn't help, so I turned it back off. I am using ALSA on the frontend, and other than the stutters, it sounds fine. Hi Michael, I had a very similar problem which cropped up after switching to ALSA output. After a long saga of list-trawling, it turned out to be an error with an uninitialised variable in Myth's ALSA audio module (I so wish C++ would regard this sort of thing as an error). After grabbing a patch from CVS and rebuilding, all is fixed. The patch against 0.17 is attached. Since we have the same frontend hw, I could look into making the (RPM) binaries available if there's somewhere to drop them. Matthew. mythtv-0.17-mppalsa.patch Description: Binary data ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
