No subject
Thu Sep 20 15:16:44 UTC 2007
processor and hadn't seen the video / audio sync issues up till 2 weeks ago
(as I mention above) when I started hosing around with the Video Settings
regarding XvMC (Had it set to Standard instead of XvMC). Switched that back
and all my video is going through just fine now.
The oddest thing about this was when I was having De-Sync problems I was
running 30 - 40% CPU with Myth (and I THOUGHT with Real Time priority though
I can't ever seem to get it to tell me explicitly that Real Time is in fact
set properly). When I was having lockups that was up to 40 - 60% (without
XvMC) but my A/V sync was sound, threw a monky wrench into my "Must be CPU
Usage" theory I was going with for a long time.
The end result I've found, and no offense intended to the Myth developers,
is that Xine handles video MUCH better than Myth does, or, possibly, Xine
requires a potload less horsepower to properly play A/V than Myth's internal
player does. I don't know whether it's less intensive code or whether
there's something about the way Xine manages it's codecs for A/V playing but
the bottom line is that it is a slightly more robust handler of video,
PARTICULARLY HD Video.
Honestly, I'd like to see a feature added to allow pre-recorded shows the
same flexibility as recorded "videos" and allow a user to select Xine as
their application to play recorded shows back through. While I realize that
we'd loose the ability to Edit (which is important) and some other
interesting features, for those people who are having issues playing HD
video through the internal player it would stop them from having to exit out
of Myth to watch what they want to watch.
When I was going through this myself I heard of a few people that had setup
their "record to" directory in Myth as the same area where their "videos"
were kept. While this mixes things up (unfortunate) it DOES allow you the
option of using Xine in Myth to play your pre-recorded shows...just not
through the "Watch Recorded" Interface that is SO HANDY.
--Douglas Wagner
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<br><br><div class="gmail_quote">On Dec 11, 2007 11:06 AM, MythTV <<a href="mailto:mythtv at blandford.net">mythtv at blandford.net</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="Ih2E3d">DaveD wrote:<br>> I am having trouble with A/V sync on some HD shows recorded from our PBS<br>> channel. It is the only channel I get that broadcasts 720p. Some shows<br>> have the problem, some do not. What happens is the video continuously
<br>> races ahead of the sound and Myth constantly adjusts, some times slowing<br>> the video, some times speeding up (and dropping parts of) the sound.<br>> It's very unwatchable.<br>><br>> Good news is I can watch the recordings with Xine or Mplayer. Both work
<br>> fine. Myth works fine on all other HD recordings (all other HD channels<br>> are 1080i). All SD works fine.<br>><br><br></div>I posted yesterday about a similar problem I am having as well.<br><br>I recorded a show last night that would exhibit the problem.
<br><br>It is a SD Digital show.<br><br>Mplayer can play it without any problem ( 7% cpu ) but mythtv stutters<br>continuously and is unwatchable.<br><br>I tried all of the predefined playback profiles and non of them made any
<br>difference.<br><br><br>Mythtv:<br>2007-12-11 10:04:53.104 NVP: Video is 30 frames ahead of audio,<br> doubling video frame interval to slow down.<br>2007-12-11 10:04:53.170 NVP: Video is 30 frames ahead of audio,
<br> doubling video frame interval to slow down.<br>2007-12-11 10:04:53.171 NVP: Video is 30 frames behind audio (too slow),<br>droppin<br>g frame to catch up.<br>2007-12-11 10:04:53.171 NVP: Video is 30 frames behind audio (too slow),
<br>droppin<br>g frame to catch up.<br>2007-12-11 10:04:53.171 NVP: Video is 30 frames behind audio (too slow),<br>droppin<br>g frame to catch up.<br>2007-12-11 10:04:53.171 NVP: Video is 30 frames behind audio (too slow),
<br>droppin<br>g frame to catch up.<br>2007-12-11 10:04:53.171 NVP: Video is 30 frames behind audio (too slow),<br>droppin<br>g frame to catch up.<br>2007-12-11 10:04:53.171 NVP: Video is 30 frames behind audio (too slow),
<br>droppin<br>g frame to catch up.<br>2007-12-11 10:04:53.254 NVP: Video is 30 frames ahead of audio,<br> doubling video frame interval to slow down.<br>2007-12-11 10:04:53.297 NVP: Changing speed to 0
<br><br>Mplayer:<br>TS file format detected.<br>VIDEO MPEG2(pid=99) AUDIO A52(pid=100) NO SUBS (yet)! PROGRAM N. 1<br>VIDEO: MPEG2 528x480 (aspect 2) 29.970 fps 15000.0 kbps (1875.0<br>kbyte/s)<br>[VO_XV] Could not grab port 355.
<br><div class="Ih2E3d">==========================================================================<br>Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough<br></div>VDec: vo config request - 528 x 480 (preferred colorspace: Mpeg PES)
<br><div class="Ih2E3d">Could not find matching colorspace - retrying with -vf scale...<br>Opening video filter: [scale]<br>The selected video_out device is incompatible with this codec.<br>Try appending the scale filter to your filter list,
<br>e.g. -vf spp,scale instead of -vf spp.<br>VDecoder init failed :(<br>Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b<br>Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2))<br>
==========================================================================<br>==========================================================================<br></div>Opening audio decoder: [liba52] AC3 decoding with liba52<br>
Using SSE optimized IMDCT transform<br>Using MMX optimized resampler<br>AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)<br>Selected audio codec: [a52] afm: liba52 (AC3-liba52)<br>==========================================================================
<br>AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)<br>Starting playback...<br>VDec: vo config request - 528 x 480 (preferred colorspace: Planar YV12)<br>VDec: using Planar YV12 as output csp (no 0)<br>Movie-Aspect is 1.33
:1 - prescaling to correct movie aspect.<br>VO: [xv] 528x480 => 640x480 Planar YV12<br><div><div></div><div class="Wj3C7c"><br><br>_______________________________________________<br>mythtv-users mailing list<br><a href="mailto:mythtv-users at mythtv.org">
mythtv-users at mythtv.org</a><br><a href="http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users" target="_blank">http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users</a><br></div></div></blockquote></div><br><br>I hate to be the one to mention this, but unfortunately I had that issue for about a year before I upgraded the box. Like clockwork, anything recorded off our local ABC Affiliate here in St. Louis would have it's audio out of sync with it's video through Myth while I could drop out of Myth and play it through Xine without any issues at all.
<br><br>As a matter of fact it happened to me no more than 2 weeks ago for the first time in ages. I was getting random Linux Lockups while playing back video (The whole machine would freeze and die, SSH unresponsive, console switches (from text to graphical or among text consoles) didn't work, etc.) and I had fiddled with some of the settings (BTW I feel like I've traced this to OpenGL in
20.2...I was using Open GL for 3 - 4 months in 20.1 and had NO issues with lockup, but I believe that's the only setting I've disabled on my system atm) including the XvMC settings.<br><br>But anyway, to get back on track with the thread: In essence A/V sync wasn't working, I'd drop out of Myth and load up Xine and everything would work perfectly fine. That was my solution for 6 - 8 months when I first started using the system.
<br><br>From there, I upgraded from a 2.8 HT Intel processor to a 3.0 64-Bit AMD processor and hadn't seen the video / audio sync issues up till 2 weeks ago (as I mention above) when I started hosing around with the Video Settings regarding XvMC (Had it set to Standard instead of XvMC). Switched that back and all my video is going through just fine now.
<br><br>The oddest thing about this was when I was having De-Sync problems I was running 30 - 40% CPU with Myth (and I THOUGHT with Real Time priority though I can't ever seem to get it to tell me explicitly that Real Time is in fact set properly). When I was having lockups that was up to 40 - 60% (without XvMC) but my A/V sync was sound, threw a monky wrench into my "Must be CPU Usage" theory I was going with for a long time.
<br><br>The end result I've found, and no offense intended to the Myth developers, is that Xine handles video MUCH better than Myth does, or, possibly, Xine requires a potload less horsepower to properly play A/V than Myth's internal player does. I don't know whether it's less intensive code or whether there's something about the way Xine manages it's codecs for A/V playing but the bottom line is that it is a slightly more robust handler of video, PARTICULARLY HD Video.
<br><br>Honestly, I'd like to see a feature added to allow pre-recorded shows the same flexibility as recorded "videos" and allow a user to select Xine as their application to play recorded shows back through. While I realize that we'd loose the ability to Edit (which is important) and some other interesting features, for those people who are having issues playing HD video through the internal player it would stop them from having to exit out of Myth to watch what they want to watch.
<br><br>When I was going through this myself I heard of a few people that had setup their "record to" directory in Myth as the same area where their "videos" were kept. While this mixes things up (unfortunate) it DOES allow you the option of using Xine in Myth to play your pre-recorded shows...just not through the "Watch Recorded" Interface that is SO HANDY.
<br><br>--Douglas Wagner<br>
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