[mythtv-users] Again: Issue trying to watch IPTV stream from ISP.

[Jean-Yves Avenard]

Hi

I posted earlier last month about how I was having issues trying to
watch an IPTV video stream using mythtv. I use MythTV from trunk,
extracted on February 8th (0.21).

When trying to watch a stream, while it looks perfect using VLC, with
MythTV it's barely usable.
At first using a url like: udp://ip_address:1234 , the quality was
awful, enormous amout of mpeg artifacts (big squary pixels
everywhere), picture breaking up etc, but excellent sound
I though this could have been an issue with my computer, so I used
that excuse to upgrade my machine from a Pentium 4, 3.4GHz to a E8200
(2.66GH Core-2-duo) with 2GB of RAM.
This did not help at all. exactly the same problems.

My ISP has been very kind and has been working with me on this and
told me to use instead the url rtp://ip_address:1234
This did improve thing a lot, picture quality is good, but it keeps
pausing every 3-4s and so does the sound which is also not in sync
with the video.

I have recorded for a few seconds two streams. One using MythTV :
tv5_myth.mpg, the other using VLC: tv5_vlc.mpg

Both files play perfectly using VLC.
Using mythfrontend, the myth recording plays just like it originally
did: lots of interruption, sound cutting off etc, the VLC recording
just looks plain weird. At some stage mythfrontend just crashed with
an error unknown codec.
Here are the files
http://avenard.org/iptv/tv5_myth.mpg
http://avenard.org/iptv/tv5_vlc.mpg

I tried mythfrontend on both my mac (core2 duo 2.4GHz) and my CentOS
box (where mythbackend is running). On both machines the effects are
the same

On the linux box, I run mythfrontend with root suid and configure it
to use real-time thread. I've tried changing the audio buffer option
and use the aggressive audio buffering, very little differences

mythfrontend while running will show plenty of errors like:
2008-02-21 12:55:06.842 WriteAudio: buffer underrun
2008-02-21 12:55:07.023 WriteAudio: buffer underrun
2008-02-21 12:55:07.253 WriteAudio: buffer underrun
2008-02-21 12:55:07.339 WriteAudio: buffer underrun
2008-02-21 12:55:11.904 NVP::AddAudioData():p1: Audio buffer overflow,
audio data lost!
2008-02-21 12:55:11.918 NVP::AddAudioData():p1: Audio buffer overflow,
audio data lost!
2008-02-21 12:55:11.918 NVP::AddAudioData():p1: Audio buffer overflow,
audio data lost!
2008-02-21 12:55:11.918 NVP::AddAudioData():p1: Audio buffer overflow,
audio data lost!
2008-02-21 12:55:11.918 NVP::AddAudioData():p1: Audio buffer overflow,
audio data lost!

I'm kind of lost now. my installation works perfectly, except for
those damn IPTV streams.
Can anyone download the 2 recordings and let me know how well it works
for them, and what you did to make it work?

Thank you
Jean-Yves