How often does Dream start to crash when decoding xHE-AAC?

[zfyoung]

Hi, I'd like to know your experience with Dream decoding xHE-AAC codec. How often does it start to crash(10min? 30min? ...)and under what circumstance that is most likely to happen?

I have tried to debug this problem but since this is a intermittent phenomenon, it is really difficult to verify even if it is solved

I've intentionally tried my version over bad SNR conditions for a hour but did not observe the problem.

[AF4MP]

Hi, I'd like to know your experience with Dream decoding xHE-AAC codec. How often does it start to crash(10min? 30min? ...)and under what circumstance that is most likely to happen?

My only experience using xHE-AAC decoding is with Radio Marti.

If the propagation conditions are very stable, particularly with low Doppler rates, then Dream will not crash for up to four hours (this can be seen on the Radio Marti logs). Otherwise, even with a strong signal, the Dream crashes may occur every few minutes.

Interestingly, KiwiSDR appears to have made xHE-AAC work well as I have not experienced any crashes while monitoring Radio Marti.

[zfyoung]

Otherwise, even with a strong signal, the Dream crashes may occur every few minutes.

If possible, can you record the DRM IF signal that will almost surely crash the Dream software? That will be great to repeat the experiment and help to verify the result. Otherwise, my effort is just a wild-goose chase! Thanks in advance .

[AF4MP]

I will be pleased to do that.

Allow me a day or two as I need to be present for the recording (most of my logging is auto and unattended).

[Digger]

On 17770 kHz I logged xHE-AAC with the following results:

2020-06-10, 0 min
2020-06-10, 1 min
2020-06-10, 0 min
2020-06-10, 2 min
2020-06-10, 1 min
2020-06-10, 1 min
2020-06-10, 5 min
2020-06-10, 1 min
2020-06-10, 18 min
2020-07-19, 33 min
2020-07-29, 9 min

[AF4MP]

If possible, can you record the DRM IF signal that will almost surely crash the Dream software?

Last night I recorded 45 mins (476.4 MB WAV format) worth of the Radio Marti xHE-AAC IF signal from the IQ output of my KiwiSDR.

As my xHE-AAC decoding is via the Linux compiled DReaM 2.2.1 I use a
Linux computer running Ubuntu 18.04 for monitoring Radio Marti. I was never able to get the Windows version of DReaM 2.2.1 to work.

It took a while to figure out the best way to record the signal (using Virtual Sink and Audio Recorder). To make sure that the IF signal was correctly recorded I monitored the replay via VLC Media player with DReaM 2.2.1.

I have found that the actual DReaM crashes, on my equipment, come in two forms. One is the hard crash that shuts down the program, and the second is a soft crash that only shuts off the decoded audio, but still shows the constellation and continues logging. This soft crash usually corrects itself after a period of time, or can be corrected by turning the program off and on.

The signal that was recorded produced 12 hard crashes and 2 or possibly 3 soft crashes. There is a good cross-section of signal propagational issues on the recording from fading, high to low SNR, and periods of higher Doppler rates. Not all of the signal problems caused crashes even though they may have lost audio.

Interestingly when replaying the signal the crashes come at different times depending at which point you start the play back. For example the first crash comes at about 8:50 minutes into the recording if play back was started at the very beginning. However if you start the recording at say 7:00 there will no crash at 8:50 as before. Sometimes there maybe a crash just after starting.

This leads me to think that problem might be more to do with the computer/software signal buffer or memory buffers than the actual decoding algorithm. I am not a software engineer nor a programmer so my speculation maybe way off.

@zfyoung please Private Message me your email address so that I can forward the recorded IF signal to you.

[zfyoung]

Hi, Zyg:
I've sent you my email-address via PM. Thanks again to you and everyone for the help here.

As what you've mentioned, I did find some loopholes in the origin version that causes memory leak/corruption. I've made some corrections, but I'm not sure if I have all of them plugged up. I have the Window10-64bit binary, maybe I can post here for everyone to test and report bug? If everything is OK, then I can share the final source code and this issue be settled?

[Owdjim]

I'd be happy for you to post test binaries here. The Forum has plenty of free space, and now accepts large file uploads as attachments. I'd also be happy to test! All I want is a 2.2 version of Dream that is as reliable and stable as my old 2.1.1-svn808!


73 Chris

[zfyoung]

Thanks,Chris.

In the attachment is .exe binary on window10-64bit. Feel free to comment on the test result. But I have to add the following disclaimer:LOL


This software is ONLY meant for valid test purposes, and under the terms of the GPL this does not mean that its use is free of rights of others. The use may infringe third party IP and thus may not be legal in some countries.

P.S. :change *.zip to *.rar and uncompress. Don't know why RAR file is not supported here.


(To reduce confusion Site Admins have repacked the files as proper .rar & .zip archives and added them as the -proper attachements. The .zip is a ZIP archive and the .rar is a RAR archive )

[zfyoung]

Hi, Zyg. I did the test on your IF over a period of 45min. My revised DReaM did well with xHE decoding and did not notice any anomaly.

Attached is the log file. Please disregard the timing.
Note: the *.doc is actually *.csv

[AF4MP]

Hi, Zyg. I did the test on your IF over a period of 45min. My revised DReaM did well with xHE decoding and did not notice any anomaly.

That is excellent!

Now I have to get your Dream version to work on my Windows 10!

[Owdjim]

.rar is now a supported attachment type. The previous administrators had not added it.


73 Chris

[Owdjim]

This is definitely the best v2.2 build for Windows 10 I've tried so far. I can do things without instant crashes, and the non xHE-AAC decoded audio is listenable.


Signals at home are very weak today, but I've been decoding the IQ stream from the NZRDXL's Northland KiwiSDR.


xHE-AAC on CNR 17770 kHz decoded partly before getting too weak.


Currently I'm listening to the AAC on 13825 without any issues.


I miss the receiver CAT control for my own receiver though.


Well done!


73 Chris

[AF4MP]

I totally agree! Check out today's Radio Marti xHE-AAC reception logs.

Zfyoung's DReaM V22x super software did not crash or falter in any way. The KiwiSDR receiver inadvertently locked up once half way through the 9-hour period, but the decoding software continued without any problems.

Zfyoung, thank you for all the hard work that you have put in to this program, and thank you for sharing the results of your effort with us. It is most appreciated!

[Owdjim]

Another small thing I discovered: this build doesn't seem to accept 'https:' encrypted URLs for the "DRM URL" schedule parameter in Dream.ini


V2.1 & the Zefie V2.2 build do. I guess different network libraries being used?


73 Chris