TV Hat Driver issues?


We’re just playing with a Pi 4 and TV Hat. It’s basically working, however we have struck a problem which could use some advice on. We have tested a number of DVB-T streamers, inc TVHeadEnd, Mumudvb and dvblast. The latter is the one we want to use because it supports rtp encapsulation of mpeg-ts over multicast udp.

We gave up quickly on tvheadend because the IP streaming transport options were too limited.

What we found was that with both mumudvb and dvblast they report errors that are somewhat similar, in the latter case:

error: DMXSetFilter: opening device failed (Too many open files)

and this is repeated a number of times. The effect of it is that only a couple of the demuxed channels from a given service frequency actually end up working concurrently, when it should be possible to have them all streaming concurrently.

This does not seem to be a problem of too many open file handles generally, it’s more specific to something in DVB device driver chain.

Any ideas?



I’ve mainly worked with HDHomeRun network tuners in the past, but I might be able to take a stab at this one. My understanding is that it solves the problem by having multiple tuners to demodulate individual channels from the signal, rather than demultiplexing one big stream.

I’ll give this some more thought tonight, and let you know my thoughts tomorrow.



Hi James - thanks for your reply but this is not an issue concerning multiple tuners. (I’m also familiar with Silicon Dust stuff). It’s about demuxing multiple programs that are part of the same channel. There just seems to be a descriptor limit baked in somewhere in either the TV Hat drivers or some other part of the stack that won’t allow more than a few streams to be opened concurrently?

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