[mythtv-users] Terrible LiveTV performance

[Curtis Stanford]

Just to follow up on my own post, I really think this is a mythtv problem. I 
started up the frontend and was watching the console messages. I went Live TV 
and got the normal stuff:

connecting to backend server: 10.0.0.5:6543
Input #0, mpeg, from 'rbuf://10.0.0.5:6543/media/video/ringbuf1.nuv':
  Stream #0.0: Video: mpegvideo, 480x480, 29.97 fps, 6000 kb/s
  Stream #0.1: Audio: mp2, 48000 Hz, stereo, 384 kb/s
Opening OSS audio device '/dev/dsp'.
Over/underscanning. V: 0.050000, H: 0.020000, XOff: 0, YOff: 0
Using XV port 56
Changing from None to WatchingLiveTV

Then, I hit channel up and all hell breaks loose:

rebuffering (243713 256000)
Delaying to next trigger: 206784
Delaying to next trigger: 227785
Delaying to next trigger: 239087
Delaying to next trigger: 245684
Delaying to next trigger: 257767
Delaying to next trigger: 269170
Delaying to next trigger: 283405
Delaying to next trigger: 294443
Delaying to next trigger: 305797
Delaying to next trigger: 299890
Delaying to next trigger: 324516
Delaying to next trigger: 339098
Delaying to next trigger: 346693
Delaying to next trigger: 361066
Delaying to next trigger: 369218
Delaying to next trigger: 383587
Delaying to next trigger: 391067
Delaying to next trigger: 402502
Delaying to next trigger: 413431
Delaying to next trigger: 427829
Delaying to next trigger: 439188
Delaying to next trigger: 450028
Delaying to next trigger: 461107
Delaying to next trigger: 445005
Delaying to next trigger: 480445
Delaying to next trigger: 491434
Delaying to next trigger: 502865
Delaying to next trigger: 517163
Delaying to next trigger: 526256
Delaying to next trigger: 539480
Delaying to next trigger: 547129
Delaying to next trigger: 558103
Delaying to next trigger: 569560
Delaying to next trigger: 583824
Delaying to next trigger: 591424
Delaying to next trigger: 606081
Delaying to next trigger: 617081
Delaying to next trigger: 628163
Delaying to next trigger: 621044
Delaying to next trigger: 647026
Delaying to next trigger: 658193
Delaying to next trigger: 669517
Delaying to next trigger: 683809
Delaying to next trigger: 694736
Delaying to next trigger: 702767
Delaying to next trigger: 715114
Delaying to next trigger: 724821
Delaying to next trigger: 739617
Delaying to next trigger: 750411
Delaying to next trigger: 761486
Delaying to next trigger: 770746
Delaying to next trigger: 783702
Audio buffer overflow, audio data lost!
Audio buffer overflow, audio data lost!
Delaying to next trigger: 772746
Delaying to next trigger: 787773
Audio buffer overflow, audio data lost!
Audio buffer overflow, audio data lost!

and so on, indefinitely...

Just another clue.

By the way, occasionally, the channel change does work correctly but not very 
often.

On August 14, 2003 10:02 am, Curtis Stanford wrote:
> I'm glad other people are having this "changing channels" problem. I've had
> this for a while but thought it was my ivtv driver. You don't even have a
> PVR-250 and have the same problem. Interesting...
>
> On August 14, 2003 10:22 am, Paul Jara wrote:
> > I used to be able to watch live TV with MythTV without much issue. I've
> > got a P4 2.2 with 512MB RAM, and MPEG-4 480x480 live TV was quite
> > smooth. However, for the best part of 4 months, I've been using MythTV
> > solely to record shows and have been watching these recordings later.
> > I've been upgrading MythTV in this time period. This past week I just
> > got into using the live TV functionality again, and the performance is
> > just terrible on my machine. There are a couple of issues. I've been
> > using the RPMs but 3 times I've compiled from source and the problems
> > still remain. Interestingly enough, they are often worse when compiling
> > from source.
> >
> > 1) Slow-motion video after changing channels. When switching to live
> > TV, the first channel is quite viewable and performance is great - the
> > video is fluid with no dropped frames. Changing channels though causes
> > the audio to drop out, and the video to continue in slow-motion. The
> > only workaround is to exit out of live TV and restart it, at which
> > point the cycle continues with the initial channel working as expected
> > and subsequent channels not working properly.
> >
> > 2) Jerky video after changing channels. I've cleaned out and
> > re-installed MythTV about half a dozen times. More often than not, this
> > issue is the consistent one with issue 1) happening consistently with
> > only 2 of those installs (1 being an RPM install and the other a build
> > from source). Watching live TV is quite viewable with the initial
> > channel, but changing the channel immediately results in a consistent
> > dropping of frames. Consequently, the video appears jerky and the audio
> > periodically pops. I can workaround this issue by pausing the video,
> > building up a 5 second buffer, and resuming watching, at which point
> > the video is as smooth as that produced by the initial channel.
> >
> > I'm using RH9 with the latest kernel. I've got the ALSA drivers
> > installed for my SBLive! Value. ALSA support is not compiled into the
> > RPMs, but when building from source, I have compiled it in and as I
> > said, the problems are actually worse (similar behaviour, but they are
> > more exaggerated). Not sure if this is because of the ALSA support or
> > some other variables in the build process that vary from the RPMs. I'm
> > using an Nvidia GeForce 3 and have tried the two latest binary releases
> > and the XFree86 open source drivers without resolving this issue. This
> > problem happens when using MPEG-4 and RTjpeg as the live TV codec.
> > Ditto with using uncompressed audio and MP3 audio. I've tried with
> > Jitter reduction on/off, experimental AV sync on/off, aggressive
> > soundcard buffering on/off, and the commercial skipping and flagging
> > features on/off. None resolve the problem.
> >
> > I'm sure lots has changed since April, but at one time I was able to
> > watch live TV and it was great. I'm not sure where along the lines the
> > problems started but I've also built a recent CVS version and the
> > problems remain.
> >
> > -Paul
>
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