DVB-C: stutter, other hints please? (1 Viewer)

[hansdegit]

Hey Taipan, still active on this forum? That's good news for the MP community.

I use the latest stable 0.2 release (0.2.0.4?)

I'll do a check with MP setup to verify the quality of the signal. It's a clean amplified signal, not split, directly attached to the wall-inlet. Do you know of any method to check the OHCI Firewire card? Think of interrupts etc.

Current specs:
MediaPortal Skin: BlueTwo Wide
Memory: 1024 MB
Motherboard: 'K8N' (ASUSTeK Computer INC.)
TV Card Model: FloppyDTV
TV Card Type: DVB C
TV Card Driver: 4.1.0 BDA
Video Card Model: Radeon 9550 (256 MB)
Video Card Driver: 6.14.10.6458
Video Card Resolution: 1360x768
Video Render Type: VMR9
Audio Card Model: Realtek AC'97 Audio
Audio Card Driver: 5.10.0.5620

edit: signal quality about 2/3 of maximum, signal strength too.

 

[Taipan]

signal quality about 2/3 of maximum, signal strength too.

I assume that these are readings from MediaPortal? I am not sure what they really mean, but if 2/3 = 66%, then that is way too low. You need figures that are 85% plus for "stutter free" DVB reception.

Have you tried using the FloppyDTV with the supplied TV application (My Theatre ?) - this might give you better signal strength and quality readings, and may confirm if the problem is the FloppyDTV card or MediaPortal?

Do you know of any method to check the OHCI Firewire card?

Sorry, no, I don't. Is the "stuttering" regular, or random and intermittent? Do you have any other FireWire devices connected, that could be removed?

 

[hansdegit]

I assume that these are readings from MediaPortal? I am not sure what they really mean, but if 2/3 = 66%, then that is way too low. You need figures that are 85% plus for "stutter free" DVB reception.

Oops...Yes, these are readings from MP and yes, it means 66% and some change.

The FloppyDTV is connected to an amplifier which adds 3 dB to the signal from the wall outlet. I have one port left on the amplifier, I'll try that one. It adds 4 dB to the signal. Or maybe the cable itself is faulty.

To be continued, I guess. Thanks for your help.

 

[infinite.loop]

I also had the stuttering playback problem with purevideo codecs.
Try the following:

1. start MediaPortal
2. switch to windowed mode (ALT +ENTER)
3. play any file in MyVideos or start MyTV (whereever you get the problems)
4. pause the playback
5. then start graphedit
6. and connect to the remote graph
7. now check if you only see the purevideo codecs for audio and video, if you see ffdshow, dscaler or something else in there too, then this could cause the stuttering/problems.
8. You can try to remove these additional filters and then reconnect the pins or create a new filter in graphedit with only the required filters.

If this fixes the problems, then you should check if you have post-pro filters enabled in MediaPortal, or alter the config/Merits of the codecs which were in that graph and causing the issues.

In my case, ffdshow was configured wrong, which means that it was added to every graph which was created for an mpeg2source.
the result was 100%CPU load and stuttering.

generally speaking, if you run into problems with playback, then you should:

• test with MPV/MPA (if you use other codecs)
• disabled post-processing (if enabled)
• check CPU-load during playback/watching TV
• check the created graph with graphedit
• play the file with VLC and check if it is working there

 

[hansdegit]

Well, to me it seems that the following line is hard-coded in MP:
"2007-01-01 15:33:26.546875 [Info.][7]: DVBGraph: StoreChannels() signal level:62 signal quality:62 locked:True"

I've connected various amplifier ports to the FloppyDTV; no matter what I try, those levels seem to be stuck at 62. How are these calculated?

 

[infinite.loop]

Well, to me it seems that the following line is hard-coded in MP:
"2007-01-01 15:33:26.546875 [Info.][7]: DVBGraph: StoreChannels() signal level:62 signal quality:62 locked:True"

thrust me, this line is not hard-coded

problem is that many TV-Cards do not provide "real" values for signal strenght/quality.

i.e. my Skystar2 always shows me "signal level:0 signal quality:100". and MyTV works fine.

many TV-Cards/drivers have that "problem".

 

[hansdegit]

Thanks for the explanation and your advice.

In my case, ffdshow was configured wrong, which means that it was added to every graph which was created for an mpeg2source.
the result was 100%CPU load and stuttering.

Well, actually that is what I want...I need ffdshow to resize the picture to 1360x768. The picture quality is absolutely fabulous.

And, of course, I do not want my cpu to work too hard, because that will result in noise from the cpu-fan. Watching TV almost always results in 50-60% cpu usage.

The stuttering is ONLY apparent in live-tv via DVB-C. The graph runs smoothly for DVD and analog TV.

Do I really need to pause the playback before connecting to the graph?

 

[mPod]

Watching TV almost always results in 50-60% cpu usage.

That's the result of ffdshow postprocessing. Very CPU consuming. Also all hardware acceleration is disabled in that case (caused by ffdshow, not MP). Thus your stuttering.

 

[hansdegit]

FloppyDTV malfunctioning?

That's the result of ffdshow postprocessing. Very CPU consuming. Also all hardware acceleration is disabled in that case (caused by ffdshow, not MP). Thus your stuttering.

mPod, let's not jump to conclusions.
First of all, when the CPU is at 50-60% it means that there is room for another 40-50%....Of course I understand that postprocessing is cpu-intensive, but my Athlon can cope. Easily.

Second: of course I tested this configuration without ffdshow and I can guarantee that the stuttering is not caused by ffdshow. Again, DVD's are stutter-free, analog TV too. And I use ffdshow there too.

I'm beginning to think that my FloppyDTV might be malfunctioning. Why?
- MPV also stutters. Way less than Purevideo, but yes....Some stuttering.
- dScaler exhibits some artefacts.
- PowerDVD is not free of problems.
All this only when watching DVB streams. Zapping is slow, too.
But perhaps the most compelling arument is that recorded TV also stutters on other computers using completely different codecs. As if some frames are skipped...

I'll try with another FloppyDTV tuner. Very annoying.

Thanks to all for your support.

 

[mPod]

Try MyTheatre to check your FloppyDTV. Easy.