Handling Overlap Conflicts

Beta Community DVR Beta
#1

I have a question and possible request. It seems more and more the networks aren’t lining up their broadcast schedule with the actual time slots and typically a show will start or end outside it’s designated time. I’m assuming this is the whole purpose of the “padding” settings in most DVRs.

For this reason I often add a minute to all my recordings to make sure I don’t miss the end of a show.

I’ve done some limited testing and it appears Channels is taking this into account but there is some odd behavior.

For example:
Assume only one tuner is available.
2 shows are set to record back-2-back
The first show was 1 minute of padding added

What I’m seeing in the log is that the second recording fails 3 times (error 503) once at the scheduled start time, once 30 seconds later, and again 1 minute after scheduled start which is also the exact time the first recording stops. It then checks again 30 sec later (1min 30sec total after scheduled start) and finally starts the recording.

I haven’t seen this happen when shows without padding are back to back but maybe it’s happening there too. Not sure if this is a race condition or some other error but that extra 30 seconds can really cut off an important segment of the show. Wondering if it could be set to try at scheduled time then 1 sec later, then 31 sec later, etc to try to avoid the conflict? What would be even better (not sure of feasibility) would be for both recordings to use a single tuner for the small overlap if they are on the same channel.

#2

Agree this would be ideal, but it is tricky to implement. It also doesn’t help if the programs are on different channels.

For the moment, the only way to guarantee that you record everything you’re trying to (including padding) is by making sure you have enough tuners available.

#3

How about something semi-intelligent where, if two shows are back to back and there are insufficient tuners, it ignores the end-padding of the first and the pre-padding of the second? It’s not ideal, but it would prevent some shows from being lost.

#4

Tricky to do right because the DVR doesn’t necessarily know how many tuners are available. Even if a tuner is on the network, it might not have a good signal and could fail to tune. And the only way for the DVR to know which tuners are in use (possibly by other programs even, like Channels streaming live tv), would be to try to ping the hdhomerun constantly to fetch that information.

#5

Another option for devs is to change DVR timing… first end recordings at specified time and then start new recordings, rather than trying to start new recordings and then end previous.

Luckily, Channels DVR does keep trying to start recording (up to three minutes?). Some other DVR solutions try once and fail, (no retry).

Absent adding additional tuners, Channels has the ability to override your settings default…on a pass or job.

Hence, if you set your end padding default at 1 minute, you can change that first (pass/show) to use 30 sec or 0 instead. All depends on the show behavior from the broadcaster.

#6

@revrag Are you adding padding to compensate for the funny start/stop times? Because while programs are scheduled to start at times like 9:01p and end at 10:01p, Channels DVR doesn’t just record on solid hour blocks. The guide data actually knows the funny times and starts/stops according to them. So there’s no need to add padding to compensate for them.

The retries you’re seeing is the DVR trying to cover for exactly the issue you brought up. There’s cases where one program might end at 10:01p but another starts at 10:00. If you only have 1 tuner, then there’s a conflict for 60 seconds. So the DVR tries every 30s for up to 180s to start recording. If you’re adding padding to the end of the first recording, you’re going to push it over the 180s window and actually create the conflict.

Of course, you’re going to miss a little of the first program, but it’s either this, or just live with the conflict and not record at all. There’s not much you can do about this. So we put a 90s window on there. And if it can, it will start the recording.

The easier solution to this of course, as @tmm1 mentioned, is to just stack HDHomeRuns so that you have more tuners available. Unlike other DVR boxes, you can actually add as many tuners as you want with Channels DVR. If conflicts are a concern, it’s an investment worth considering.

#7

Thanks, that makes sense. It does seem the networks often fail to air the entire show in the time window they say they will.

The one thing I was pointing out is that the second retry (for a 1 minute pad) fails even though the first recording is ending (at the exact same time). If the check for the available tuner on the retries could wait until the previous recording ended that seems like a better solution. Then maybe you miss a second or two instead of having to wait until the next 30 second interval check.

#8

Yeah totally.

I think the moral here is, don’t abuse padding. Reserve it for things like fixing channels that tend to not respect their schedule, like BRAVO does, or for extending time at the end of a live event.

Trust the DVR for everything else.

This is a good point though, thanks.

#9

We are testing a new feature where back-to-back episodes with overlapping padding can share a single tuner instead of requiring two.

If you’d like to help test this before it gets released to everyone, run the command in Volunteers to test new DVR build?