Live TV and a weak DVB-T signal

[daveslee]

I'm on a quest to oust Kodi from my chain of distributed house-wide TV viewing. I'm having trouble getting NPVR to reliably show Live TV with weak signals.

First some pre-amble:

My line of sight to the main DVB-T transmitter for the area is blocked by trees. It's spring and the leaves are coming in so my DVB-T signal has weakened. I used to have NPVR record DVB-T and it coped really well with drops in signal and corruption of the resulting .TS files. Live TV playback was troublesome.

Over the winter I added a DVB-S twin tuner (PCI) on UK Freesat. This gives me all the main channels for my recordings on two tuners. I kept the two USB DVB-T sticks for four more DVB-T receivers to cope with (1) When as a household we need to record three things at once and they don't share the same transponder etc on DVB-S (2) to get a few channels that are available on DVB-T and not a UK-Freesat DVB-S or otherwise legally free to air on DVB-S. For those in the UK, mainly "Dave" and "Quest". So I set my preferences and channel order so that the DVB-S tuners are used first for recordings, then DVB-T only if necessary (overflow or oddball DVB-T channels) and set my live channel preference to be reverse so that the DVB-T tuners would be used first for live stream/small time shift.

And I'm very happy with recordings. I've been using the Kodi plug ins and using Kodi on various PCs around the house to watch the recorded TV, as well as WD Live boxes that get copies of the .TS files where I don't want a PC next to a TV.

Kodi can "call up" a live TV stream via NPVR and it sort of nearly works. Streams play for a few minutes then there is a click-crunch-pause-blip and then the stream continues.

But NPVR natively does something different. Logs included...

In this log from a client to an NPVR server called "DVB-S" (but including the DVB-T tuners just to confuse you!):

* I allow the remote client to start up and grab a whole pile of stuff
* I right click and use the channel selector to pick Channel 1 - BBCNE&C - a good strong signal on DVB-T
* After quite a while (understandable) the channel is tuned and begins to stream.
* I change channel (on the fly) to 2 - BBC Two
* This fails and I have a blank screen
* I choose stop
* I use the channel selector to tune to 2 - BBC Two
* This time it succeeds
* I am able to stop playback of the live stream
* Then I tune to Dave - a weaker DVB-T channel
* It plays for a short while then I see tell-tale mosaic-ing of the picture
* Rather interestingly - in the debug window (which I had on in case it helped), the playback position became a massive negative number but the file extent (in time) continued to progress
* I was able to press stop without a crash
* Then I use the channel selector to pick QUEST which is the weakest signal I can receive
* I get a few frames, debiug shows the massive negative position and playback stops
* I press stop then exit NPVR

Now here's my sort of question and thinking...

Does the playback engine in Kodi for .TS files handle over-running the end of the file/stream more gracefully than that in NPVR? I could see how with my dodgy recordings or "trick play" like pausing and fast forwarding and rewinding that there could be circumstances where my "playback position" would not correspond with availability of stream or file to playback? When nearing the end of the stream/file does Kodi kind of pause or slow down to see if more appears (true end). Does the NPVR engine just see that the playback position (presumably "clocked" from local time) is beyond the timestamp for the end of the data and end?

I see odd behaviour with dodgy recordings with my WD Live boxes, especially in "trick play" like pausing, fast forward and rewind - the progress bar blips back and forth and sections repeat over and over again, like the WD Live box is periodically trying to resolve "clock time" with "playback position" with "file-sequence time".

I guess that advice is going to be to run more cable from the satellite dish, find a PC with more PCI slots and add more tuners on DVB-S for live playback and give up on some channels that are DVB-T only and watch their catch-up web-streams instead. But if you have insight into the way that NPVR plays back TS files/streams then that would also be great - in particular what is the significance of the massive negative number in the debug window when the end of file/stream seems to be over-run. Investigating this might lead to improved "trick play" in live streams and make NPVR time shifting even on "clean" files even better.

Thanks in advance.

[Graham]

Years ago, before digital switchover, my experience was more pr less identical ... including leaves and trees causing problems.

The data that is used to skip back and forth is one of the first victims of dodgy reception ( I suspect the frames get dropped due to poor reception and the timeline data gets muddled by the missing frames). The huge number is a symptom of a shagged timeline.

I spent months messing with decoders and everything under the sun and the only solution that helped was a huge pole to raise the aerial higher.

My only suggestion is to try every decoder that you can get your hands on ... but try them one at a time ... install then test then uninstall.

[mvallevand]

Does the playback engine in Kodi for .TS files handle over-running the end of the file/stream more gracefully than that in NPVR

In my experience the Kodi client has much better buffering and error recovery then NextPVR's client protocol using any decoder. Garbage in garbage out though.

Martin