Recordings Failing with "No Errors but no Data Delivered" message

[jcole998]

I've got some new informatiom about my zero-length problem.

Many hours of testing has shown the following, on my machine at least:
- A port(36312-36323) that has had a recording stopped for any reason is never released for re-use. If I try to watch live TV on such a port, I get no video or audio. Escape key exits live TV back to menu.
- If I stop watching live TV using the escape key. the port is released about 60 seconds later.
- As shown below, ports 36313, 36314, 36317 and 36320 will produce no video when it's "their turn" to be used.
- Restarting the recorder service results in errors for port 8968. Un-released ports are released but no further tuner access is possible.
- System must be rebooted to return to normal operation.

I can do this every time.

Logs attached.

Any help?

[ATTACHMENT NOT FOUND]

[jcole998]

Additional testing verified that a scheduled recording that gets assigned to an un-released port will produce a zero-length file without error.

I can now "manage" this problem by tracking when all ports a stuck. Then reboot the system.

Hopefully, a fix can be found.

[mvallevand]

Have you tried disabling your parallel processing file? https://forums.nextpvr.com/showthread.ph...post514791 I do not really like your method as I feel the /k might leave a thread open.

Martin

[jcole998]

Problem solved.

A great call, Martin! I disabled ParallelProcessing.bat as suggested and the ports used for recording are being released for re-use. It also cured that nasty message when I tried to re-start the recording service.

Now I'm back to my original problem. NextEnd.exe is not getting started when a recording starts or, if it is being started, I can find no evidence that it did. NextEnd.log is not created or updated. NextEnd.exe will run if started from the command line in a command window.

Can you explain the exact mechanism that NextPVR uses to start the batch file?

Thanks for your great help.

[Graham]

Can you explain the exact mechanism that NextPVR uses to start the batch file?

This is probably not exact ... but should be close.

Firstly ... some context. I can start a Command Prompt. The Command Prompt window will be in my user folder c:\Users\Graham. I can type the command "fabsplat" that contains the command ... notepad bolost.txt ... The command processor will expect the bolost.txt file to be in the current folder ... i.e. c:\Users\Graham

NextPVR batch files run in the context of the system user account so they are "in" a folder that might be c:\Windows or C:\Windows\System (or whatever). All file references need to be specified in full. Not bolost.txt but c:\Users\Graham\bolost.txt

The parallelprocessing batch file starts at the same time that the NextPVR Recording Service starts recording the show.

Thought for the day ... Have you tried a "sleep" command at the top of the batch file to give NextPVR a minute or so to get its act together before the batch file proper starts?

Edit: Apologies if, as I suspect, I am teaching you to suck eggs.

[jcole998]

Nah, no worries, Graham. This stuff ain't rocket science but it can drive one nuts! I'm an old-time programmer and one of my best mantras was "Hack it 'til it wiggles." I shall persevere.

I'll try your suggestion and see what happens.

Thanks for your help.

[jcole998]

No go on the delay. I used "ping 127.0.0.1 -n 6 > nul" to delay 5 seconds.

I'm hoping sub will pick up on this and add a leeeetle more logging.

Thanks again for the help.

[mvallevand]

You won't need a delay or anything like that. NextEnd is slightly different form other processes because it only uses the batch file to trigger the start of another process and return control to NextPVR. It might have something to do with the use of powershell in Creator's Update but I need to do some more research.

Martin

[Kong]

I had this exact same problem. Recordings on my HDHomeRun PRIMEs would randomly record zero-byte files. At first rarely, but later more and more. Live TV would just show a black screen with no sound. HDHomeRun Config GUI would show the correct channel locked with 100% signal strength. Restaring the Recording Service didn't help, but a reboot did.

Following jcole998's lead, I found a bunch of listening ports open in Resource Monitor. Then following mvallevand's lead, I found it was caused by my batch scripts not finishing.

I use PostProcessing.bat and PostCancel.bat to call a VBS script I wrote that renames a file when it finished recording. Looking in Task Manager I saw ~20 instances of cscript.exe running. And looking in Process Monitor, I saw them all getting sharing violations trying to open BatchProcessing.log. I traced it back to a bug in my script where if it failed to open the log file, it would retry in a loop, but I forgot to clear the error state, so when it opened the log file successfully, it would continue retrying forever. All it took was 2 recordings to finish at the same time and one script would write to the log file while the other got stuck in an infinite loop. From then on all subsequent scripts would also loop. I corrected my code and the problem went away. Many thanks for your help gentlemen.

Sub: despite this being my fault, if a process spawned by a batch file runs long, NRecord.exe should not keep the port open. Worse, subsequent recordings should not re-use a locked port while pretending to record successfully. I recommend launching the batches asynchronously or at least don't wait for them to terminate before releasing unmanaged resources. Also might be worth checking whether a port is in use before re-using it. This would help make NPVR more bulletproof