Playback Failing on Glitches

[Lao Pan]

Since upgrading to 3.4.8 I have seen several occasions where a glitch in a recording (I presume) causes video to freeze but the sound to continue - as reported in some other threads skipping forward gets things to continue.

In the attached log Started NPVR went to recordings, problem file, skipped forward 4 mins, then after about 1 min the picture freezes and sound continues.

This is with the setup.exe dated 04/05/15 which should have the latest NShared.dll patch, also NextPVR.exe and Unmanaged.dll have been patched - unmanaged.dll has stopped the logs being flooded with a new line every 11 milliseconds during playback.

These glitches have not caused freezing in previous versions of NPVR, just a short jump.

[sub]

I really can't think of anything that has changed in the playback code, so I'm not sure what might have caused that.

Have you got a specific recording that has this problem in the same spot every attempt? If so, I might need to get hold of that recording so I can try it here.

[Reddwarf]

@Lao Pan, have you tried other codecs?

[Lao Pan]

I really can't think of anything that has changed in the playback code, so I'm not sure what might have caused that.

Have you got a specific recording that has this problem in the same spot every attempt? If so, I might need to get hold of that recording so I can try it here.

Yep the one in the logs - and I've just realized what is causing the glitch - exactly 2+3 minutes into the recording - when other recordings finished there was a large amount of disk activity - one hour later watching an in progress recording caused the screen to blank out when it happened then - just got to find out what's causing this disk activity.

[BrettB]

Yep the one in the logs - and I've just realized what is causing the glitch - exactly 2+3 minutes into the recording - when other recordings finished there was a large amount of disk activity - one hour later watching an in progress recording caused the screen to blank out when it happened then - just got to find out what's causing this disk activity.

It sounds like you are seeing the same behavior I described here:

What I found was that when my playback would hang, there were HUGE (48-65 MB/s) writes going to the recording disk (a local SATA drive) for one of the shows being recorded from an HDHR Prime tuner. So I began to watch the physical disk activity on the recording drive more carefully. What I found was that for the shows being recorded from the ATSC HDHR, there would be pretty consistent writes (1.6-1.8 MB/s) to the .ts file and (about 2 KB/s) to the timing.info file. And for shows being recorded from the HDHR Prime, there would be periods of many minutes between writes to the .ts file and when they did occur, they were these huge 48-65 MB/s writes for about 30 seconds each that would temporarily block out the reads for the playback. (Upon more investigation, I am wondering if these may not be writing out to the physical disk until the recording completes and then writing the entire file at once!)

[sub]

To let me check disk usage while recording, create a c:\temp directory, and set HKEY_LOCAL_MACHINE\Software\Wow6432Node\NPVR\LogFileWriter=1 (DWORD), then reproduce the problem, then zip and attach the c:\temp\file-writer*.txt files.

[BrettB]

To let me check disk usage while recording, create a c:\temp directory, and set HKEY_LOCAL_MACHINE\Software\Wow6432Node\NPVR\LogFileWriter=1 (DWORD), then reproduce the problem, then zip and attach the c:\temp\file-writer*.txt files.

You can get a .zip archive with the file-writer*.txt files, the log files, and a set of screen shots showing the disk activity here: https://bowmantech-my.sharepoint.com/per...40f99e2073

I started 3 recordings. First was Burn Notice which was recorded on the HDHR Dual (via ATSC BDA drivers). You can see in the screen shots that it has pretty consistent disk writes going on throughout the recording. Next I started Hawaii Five-0 on one of the HDHR Prime tuners. Notice from the screen shots that nothing from that recording is actually being written out to the physical disk at that time. Then I started Prospectors on another HDHR Prime tuner. Again nothing gets written to the physical disk at first. During recordings, there were a few times when a little bit gets written to the disk for Hawaii Five-0 (screen shots in the middle of the time period). Then when the Prospectors post-padding ended, the huge writes to the disk show up. At 7:41 pm, I manually cancelled Burn Notice and let it finish its writing to disk, etc. And then at 7:43pm, I manually cancelled Hawaii Five-0 (which triggered its huge writes).

[sub]

Next I started Hawaii Five-0 on one of the HDHR Prime tuners. Notice from the screen shots that nothing from that recording is actually being written out to the physical disk at that time.

Do you see the same behaviour when only a single HDHR Prime recording is occurring? If so, can supply the file writer logs showing just that single activity?

Make sure you restart the recording service prior to the recording, to clear the logs out.

[BrettB]

Do you see the same behaviour when only a single HDHR Prime recording is occurring? If so, can supply the file writer logs showing just that single activity?

Yes, I see the same thing with any/every HDHR Prime recording. I just started a new test for you with just a single HDHR Prime tuner in use. Do you want anything besides with files from c:\temp?

[sub]

Actually - give me a couple of minutes, I'm adding a bit more logging, then I'll post a patch.