FMP24/DSD+/Win 8.1 poor decoding

I am trying to conventionally/manually decode some P25 channels and I am getting only hisses and crackles with a ton of errors in DSD+ when using FMP24 2.4 plus DSD+ 2.8 on Windows 8.1 with the following commands:

FMP24.exe -o20001 -P59 -s1
DSDPlus.exe -i20001 -f1 -Pmp3

I get the same lack of performance if I use a virtual cable instead of the TCP link.

What's odd is that audio decodes fine if I pipe it from SDR# instead of using FMP24 or copy my DSD folder to a Windows Vista machine and run FMP24/DSDPlus on there (so it doesn't appear to be a configuration or signal issue). In addition, FMP24 outputs analog voice frequencies fine even on Windows 8.1 and the digital frequencies at least seem OK when I listen to the noise. I do not have any third-party programs running or the Windows Firewall service running, though Norton was installed in the past, and CPU/memory use doesn't seem to be a problem.

Has anyone else experienced something like this? Is there a way that DSD+ can play back the raw recordings that FMP24 can make so that I can isolate the problem?

First guess would be bandwidth. Make sure the frequencies you are scanning with FMP are designated P25.
----------
FMP24.scanlist
the format of each line is:
frequency mode description

I've tried changing the bandwidth and other options in FMP24 and it doesn't seem to help.

I have the frequencies in FMP24.ScanList and set as "P25", and things look OK in the FFT window.

Hmmm, never heard of FMP failing when SDR# works. I would think FMP used less computing power than SDR#. You might try using one of the 12.5 KHz modes like PV. You could also try reducing the gain if you are in a strong signal area.

Maybe someone else has an idea...

I'd try minimizing the FMP24 spectrum display window. That knocks down the processor loading by a fair bit. If that helps, you've found your problem.

slicerwizard said:

I'd try minimizing the FMP24 spectrum display window. That knocks down the processor loading by a fair bit. If that helps, you've found your problem.

Click to expand...

I tried that and it didn't help. SDR# can be a CPU pig when scanning using the Frequency Manager+Scanner plugin but FMP24 goes fairly easy. Moreover, I'm pretty sure the Windows Vista machine (on which FMP24 works fine) is older and not more powerful than the Windows 8.1 machine. Given that the same settings work fine on Windows Vista, I think it's a Windows setting that's bad.