Recordings "Failed with no errors, but no data delivered"

[crackulator]

Beta testing the v5 server on Ubuntu with HDHR Prime, I set it up to record three programs over the last couple nights, and they all failed with the message "Failed: no errors, but no data delivered". Apropos, the ts files are zero length.

They're all from the same channel, but I can watch that channel just fine, and my v4 server recorded a show off that same channel with no issue. The channel has no DRM and HDHR reports 100% signal strength.

I just did a short recording off a different channel, works. But I try to record off that channel, it remains zero length, and HDHR says there isn't a tuner in use.

At the end of the attached log, I just tried a manual recording off that channel, see that it is zero length and no tuner in use, grabbed the logs. What happened?

[flyingsubs]

Beta testing the v5 server on Ubuntu with HDHR Prime, I set it up to record three programs over the last couple nights, and they all failed with the message "Failed: no errors, but no data delivered". Apropos, the ts files are zero length.

They're all from the same channel, but I can watch that channel just fine, and my v4 server recorded a show off that same channel with no issue. The channel has no DRM and HDHR reports 100% signal strength.

I just did a short recording off a different channel, works. But I try to record off that channel, it remains zero length, and HDHR says there isn't a tuner in use.

At the end of the attached log, I just tried a manual recording off that channel, see that it is zero length and no tuner in use, grabbed the logs. What happened?

I think I've run into the same issue! I don't think NPVR can have two instances running at the same time. I haven't had a chance to test it but make sure your V4 isn't watching or recording TV. Not sure it this is a bug or by design.

[crackulator]

That's an interesting question. The two NextPVR's are running on entirely different hardware, so the only place where they intersect is the HDHR. Of course one should be suspicious that they wouldn't share nicely, but my early experiments didn't raise any red flags. I'm pretty certain that the original three failed recordings, when they were made, the v4 server was doing nothing (it was the middle of the night, it were neither recording nor watching), but I wasn't there to observe if there was some hanging task, and who knows, maybe the v4 server is pinging the HDHR for some reason even when it isn't doing anything obvious.

The test recording, from which the log was taken, I was definitely watching the same channel on one of the other HDHR tuners through the v4 (I mean, what else I gonna do?). So such collisions could definitely be an issue there.

Tonight I'll try a recording with v4 shut down.

[crackulator]

So, last night I shut down the v4 server and let the v5 do its recording, and it succeeded. So it appears to be some interaction between the two servers, and the most basic solution is to run only one at a time.

But putting all my observations together, it's pretty complicated. The v4 and v5 servers generally appear to share nicely, using different tuners on different channels on the same HDHR with no issue. But under some circumstances, they don't. But what exactly are those circumstances...

I think it relates to v4 using a tuner when it doesn't appear to be doing anything, not recording or watching. I'm not sure what it's doing, but HDHR reports a tuner being tuned to the previous channel on which the v4 server was tuned, and I can see CPU and network activity as though it is streaming video. When the HDHR is in this condition, if the v5 tuner tries to tune the same channel, that's where the failure comes in. At least that's my theory right now. I believe I've seen other cases where both can use even the same channel (not the same tuner) without an issue, and I've never seen a failure to stream live, only a failure to record.

I'm not sure how important this is, because running v4 and v5 on the same HDHR seems outside of normal use cases. If there is a bug, it appears to be in v4 and/or HDHR, not v5. But if I have a chance I may try to isolate it a bit more just in case it turns up something interesting.

[Graham]

The v4 and v5 servers generally appear to share nicely, using different tuners on different channels on the same HDHR with no issue. But under some circumstances, they don't.

It's a fluke when they "share nicely". I'm pretty sure that there is nothing in NextPVR to support sharing in this way.

[BrettB]

It's a fluke when they "share nicely". I'm pretty sure that there is nothing in NextPVR to support sharing in this way.

I believe that NextPVR does try to "lock" a tuner before using it, and if the lock fails (because some other system/app is using the tuner already), then it will try to use a different tuner (if any are available). At least it did in v4. I guess I haven't tested it or looked at it in v5 to make sure it still has that functionality.