Feature #4325
Warm-up period for DVB-S signals.
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Description
I have been having some issues with certain DVB-S2 signals, where when I go to record a program the first several minutes will be unwatchable, then after that the signal is fine. What I'd like to see is a way to create a scheduled recording with a "warm up" period, during which the LNB would be activated but no actual recording would take place. In other words, TVHeadend would send whatever commands are necessary to tune in the channel, but for the first X number of minutes would simply dump the incoming stream to the null device or whatever, so that when the actual recording time arrives, the LNB or tuner or whatever has already been warmed up.
I have observed this issue with several different LNB's, especially in the winter. Usually my solution is to just record the show that comes on before the one I really want to watch, but that just puts wear and tear on the storage drive for no reason. So it would be great if in the recording profiles there would be a way to specify a warm-up period in seconds or minutes. Note that I have seen a LNB or tuner take over 20 minutes to stabilize, so please don't set an arbitrary maximum time unless it's at least an hour. Thank you.
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History
Updated by Sean Micklem over 7 years ago
Also, this implies that if you set a recording to start at, for example, 8 PM, and you specify that the recording should start 1 minute early, and you specify a 20 minute warm up, then it should start the streaming of that channel 21 minutes before the show starts, but only begin the actual recording 1 minute before.
Updated by Mark Clarkstone over 7 years ago
Sean Micklem wrote:
Also, this implies that if you set a recording to start at, for example, 8 PM, and you specify that the recording should start 1 minute early, and you specify a 20 minute warm up, then it should start the streaming of that channel 21 minutes before the show starts, but only begin the actual recording 1 minute before.
There already is a user-configurable warm-up time in 4.1, by default it's 30 seconds. You also may want to try setting "Skip initial bytes" to the highest possible value, and the "Pre-recording padding" option may be of use too.
Updated by Sean Micklem over 7 years ago
Ah. Still running 4.0.9 Was the configurable warm-up time in the original 4.1 or was it added in a later point release? The reason I ask is because I can look at a different backend that's running 4.1, and I don't see that setting in there, at least not in the Recording Profiles. That one is not a point release; it just says "Build: 4.1" on the about page.
What is the highest possible value for "Skip initial bytes"? I already use that on some tuners to avoid bad timing values on recordings (where a 1 hour recording shows as 25 hours long or something like that, and you can't skip around in it). Unfortunately I have found that in 4.0.9 at least, if you set too large a value then when you try to access a channel as live TV in Kodi, if it has to wait more than about ten seconds for those initial bytes to be skipped then either TVHeadend or Kodi gives up, and at that point for some reason TVHeadend restarts itself and loses any one-off changes you have made to the recording schedule (for example, you set it not to record an upcoming show because you know it's going to be a rerun - if TVHeadend restarts itself that recording will come back!).
I don't see a "Pre-recording padding" option anywhere but if you are talking about "Extra Time Before Recordings (minutes)" I have used that, but it gives me the behavior I don't really want, which is that it records to the storage drive during that time.
I've kind of been waiting for 4.2 to do any major upgrades, because in Linux I find it's far too easy to dig myself into a hole I can't get out of without completely starting over from scratch (reformat the hard drive, reinstall the operating system, reinstall TVHeadend, then have to put in all my settings again). So I kind of try to avoid running unstable versions. In any case I would not do any major upgrade like that until the winter season for TV shows is over (probably not until June at the earliest).
Thank you for the response.
Updated by Petar Ivanov over 7 years ago
Already have this option in 4.1 and last from git:
Updated by Sean Micklem over 7 years ago
Okay, got it, that's exactly what I was requesting. The reason I didn't see it is because that's apparently a newer build of 4.1 than the one I am looking at. This one does not have the "Extra warming up time" setting and instead of the "Pre-recording padding" it has "Extra Time Before Recordings", which I assume is the same setting with a different name.
Updated by Mark Clarkstone over 7 years ago
Sean Micklem wrote:
Okay, got it, that's exactly what I was requesting. The reason I didn't see it is because that's apparently a newer build of 4.1 than the one I am looking at. This one does not have the "Extra warming up time" setting and instead of the "Pre-recording padding" it has "Extra Time Before Recordings", which I assume is the same setting with a different name.
You're technically already running unstable, just an older version :p
Updated by Jaroslav Kysela over 7 years ago
- Status changed from New to Fixed
This feature is in 4.2.