Portions of recordings are missing

[MovieBuff]

Hello all,
During the past few months, I have been experiencing an increasing number of recording failures where the recording starts on time and finishes on time, but when I view the recording, a large portion of the program does not appear in the playback.  The missing portion begins just after the pre-pad, when the show would have started recording if there had been no pre-pad.  Immediately following the pre-pad portion of the recording, the playback has a brief moment with some pixilation and then playback resumes, but the playback has jumped far into the program.  After examining a couple of recent failures, it looks liked the missing portion is exactly 1 hour in length.  The playback then continues and concludes at the scheduled end of the post-pad.  As far as I can tell, NextPVR appears to be recording normally throughout the entire program. 

I didn’t see anything like this in the blog, and so I thought I would contact you to see if you have any ideas of why this might be occurring and what I might be able to do to avoid this.

I have a standard pre-pad of 3 minutes and a post-pad of 33 minutes, in case there are unanticipated schedule shifts.  The recording skip only seems to occur in movie files, and not in other programs, maybe because the movie files are longer than most of my other recordings.  The skips occur in programs recorded from multiple channels and do not seem to follow any pattern that I have been able to detect.  Not all recordings on these channels fail, and most are OK.  I have had the same pre- and post-pad setups for a long time and did not experience any issues until it seemed to start occasionally late last year with recordings on one channel, but seem to be getting more frequent and now occur on recordings made on multiple channels.

I do not have any recent examples of this, but I had some instances where I was making a recording on the same channel immediately before the failed recording, and that program continued to record during the post-pad.  The post-pad recorded just fine and correctly recorded a portion of the same program that did not record in the scheduled recording.  When this first started happening, it appeared that I was only missing about a half hour of the scheduled recording, and I was able to watch the missing part of a program if I had recorded the preceding program and could then watched its post-pad.

I have tried playing the files in NextPVR, Kodi, and VLC, and the skip occurs in exactly the same spot in each application.  When I view the most recent failure in VLC, I can see that the timestamp in the recording jumps exactly one hour starting at the end of the pre-pad, changing from 0:03:01, just before it is ready to display 0:03:02, and about a second later, the next timestamp that appears is  1:03:03, a jump of exactly one hour.  In NextPVR and Kodi, the timestamp continues constantly, and does not reflect a change due to the skip to a much later part of the program being recorded.

I am running Windows 10 Pro and NextPVR version 6.1.5.231022.  My tuner is a SiliconDust HDHomeRun Flex 4K, Model HDFX-4K.  I have not made any recent hardware or software changes, other than re-installing Kodi last week for an issue unrelated to the failed recordings.  The recently failed recording started at 16:57 on January 29.  I have also copied this failed recording to onedrive/googledrive with the following link.

https://drive.google.com/drive/folders/1...sp=sharing

Log files attached below

Thank you very much!

Jon

[mvallevand]

In the timing file you posted you can see the jump in the internal time stamps too

frame,88111.382089,34357564,
frame,91713.013456,43479888,

Basically NextPVR captures the timestamps from the source and cannot modify them. Version 7 NextPVR.exe might be a little better playing a file with bad time stamps and the web player too since they can use the timing file but other decoding issues can come into play Your best bet it to transcode but if you don't use the web player maybe try a fast remux to mp4 or mkv, and rename the timing and ts file and I expect it could work well in Kodi but it can't bring back the missing data.

Martin

[MovieBuff]

Thanks Martin,
I'm not sure that transcoding to another format would restore the missing part of the program.  Would you have any idea why exactly an hour's portion of the program would not record, or maybe be overwritten by later part of the program?  In those instances where the post-pad of another program overlapped the scheduled program, the post pad recorded those portions of the program that were missing in the scheduled recording, so it would seem that these portions of the program were actually transmitted by the station and captured by my tuner, then recorded in one program's file, but do not appear in the scheduled program's file.

[mvallevand]

We'd need to see the logs when this occurs. Are you running current HDHR firmware? There are bugs in some old firmware where the NextPVR setting was not set correctly.

Martin

[MovieBuff]

I think the logs that I attached covered the time period when the recording jumped forward, but (in my limited experience of looking at these logs) I didn't see anything in the logs that appeared to indicate that it was experiencing any issues with the recording. 

I haven't updated the HDHR firmware since I installed it a year or two ago.  I can do an update to the HDHR firmware, as well as upgrading to the latest version of NextPVR, and then making more test recordings to see if I have another failure. 

Do you have any guidance or reference to a blog post for any settings that I should be sure to select when updating the HDHR firmware?  If not, I'll note my current settings and be sure to replicate them, since they had seemed to work well for some time before this problem developed.  The unit has 4 tuners, and with my pre- and post-pads I have made recordings with all 4 running simultaneously (possibly more since NextPVR can record multiple sub-stations on a given wavelength).

If I have further problems after the updates/upgrades, I'll post further information.  Are my current NextPVR logging settings OK in case I detect another failed recording?

Thanks very much! 
Jon

[mvallevand]

It probably isn't firmware. By using ATSC mode (for multi-rec) you can potentially have network issues that aren't available with http. If you do use a VPN that could cause issues that aren't logged.

I hadn't checked the logs, because you posted not having recent examples, but those logs are clean. If anything your signal strength is unusually perfect so if you added a booster that could cause problems too. You can delete record-COPY.log your created since that is big and won't get purged by NextPVR so it might make a future log file too large to attach. SiliconDust can also monitor your device if you post on their forum and they might see things we don't

Martin

[MovieBuff]

I wanted to provide an update for this thread.  As suggested, I upgraded NextPVR to the current version, but the skipping problem continued, so I backed up my files and then did a clean install of NextPVR.  I felt this would indicate whether there might be any issue in my existing database.  But the skipping problem continued, which seemed to suggest that there was nothing in NextPVR contributing to the issue. 

Also, just in case there was some problem with the location where I was recording the data, I also changed the recording directory to another drive, but this also did not resolve the skipping problem.  I’m not using a VPN, just a normal connection to the internet.  At your suggestion I did contact SiliconDust to check whether my signal strength from the signal booster might cause a problem.  They indicated that the strong signal should not cause a problem in traditional broadcast frequencies, but did recommend a filter to protect my system from excessively strong LTE and 5G cellular signals. 
 
At this point, I felt that I had eliminated all possible sources for the failures except the tuner, and so I purchased another SiliconDust HDHomeRun Flex 4K tuner to replace my existing one.  Since installing the new tuner and scheduling several dozen test recordings, I have not experienced any skipping failures.  This seems to confirm that the problem indeed had something to do with the old HDHR tuner.

I don’t understand why the tuner would care about whether it was recording the pre-pad or the show itself – as far as I can tell from looking at the logs, the tuner would not even know the difference from the pre-pad vs the actual show once it had locked a signal and started to transmit – but I couldn’t think of any other failure point that I hadn’t tested, and the test recordings before and after its replacement seem to confirm that some problem had developed with the tuner, and that it was the failure point causing the skipping issue.

Thank you very much for your willingness to help with suggestions and explanations, and for providing us with such a great application!