Backend on Pi 4

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jfabernathy
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Re: Backend on Pi 4

Post by jfabernathy » Thu Apr 08, 2021 9:21 pm

marks7389 wrote:
Thu Apr 08, 2021 9:04 pm

How's that encoded? DVB-T2 here is rarely more than 2GB/hour for h264 encoded 1080i content these days. MPEG2 encoded SD content tends to be well under 1GB/hour.

On the plus side, so long as it only pulls the data it needs for the channels being recorded I'm never going to have a problem with capacity on the network link and the majority of what we record is carried on the same mux, there's just typically a lot crammed into them.
From a practical side I have tested a HDHR Quatro plugged into a gigabit switch along with a RPI4 and all my 37 other devices and can record at the same time 4 HD programs, 2 1080i and 2 720p, while watching a pre-recorded program using the same RPI4 as the frontend. While I don't like the quality of the RPI4 as a frontend generally, it is viewable. I regularly have recorded 4 HD programs while watching a recording using a Nvidia Shield TV as the frontend.
I'm thinking a Fire TV 4K stick as frontend if necessary which I'll probably end up doing anyway for the TV in the bedroom. Will see how it goes.
1. OTA ATSC 1.0 in the USA is always MPEG2 so it's a lot of data.

2. My wife uses a FireTV 4K for her TV and it's fine. Leanfront is particularly good on the FireTV 4K

marks7389
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Re: Backend on Pi 4

Post by marks7389 » Sun Apr 11, 2021 12:46 pm

Had an initial play with it yesterday. Don't have storage or tuner as yet - just the Pi, so installed the OS and MythTV Lite v31 on an SD card and ran the Pi-Utils script to get a fully functioning combined BE/FE. I then imported my existing database, upgraded the schema with mythv-setup and mounted the recordings over the network with NFS.

I have to say I'm impressed so far with the playback capabilities. Easy to set up and is working well.

Hardware decoding of 1080i H264 content using MMAL isn't giving me the best results. I'm seeing quite a bit of combing on fast moving objects. Video playback profile configured as recommended here:

https://www.mythtv.org/wiki/Raspberry_Pi

Software decoding seems to be much better though, and the CPU quite capable of managing it. May be worth some more investigation, but would be interesting to know if anyone else has experienced similar.

cliveb
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Re: Backend on Pi 4

Post by cliveb » Sat Apr 17, 2021 5:23 pm

Last year I did a test install of MythTV on a Pi4, using MikeB's excellent helper scripts. Got it all working nicely. Then I had to repurpose my Pi4 temporarily for another use and didn't bother to keep what I had done, on the assumption I could easily rebuild it later.

I just came back to rebuild the new MythTV system and it's now failing to install MythTV_Light. From the wiki, I gather that the Debian install image has moved away from dl.bintray.com and is now somewhere called dl.orangedox.com. So my intention was to download the necessary .deb file from there, but am running into a problem:

When I attempt to download the file, it goes to drive.google.com (I presume that dl.orangedox.com is hosted there?) which says that it can't virus scan it. When I then tell it to download it anyway, it seems to just go round in circles, and keeps telling me that it can't virus scan the file. I can't find any way to force it to download.

Can anyone explain how to actually install mythtv-light on a Pi4 from its new location?

EDIT: OK, scrub that. I was using Firefox when I couldn't get it to download. Just tried again with Chrome and got the files. Weird that the "download anyway" button didn't work in Firefox. (Almost makes you start wondering about some kind of Google conspriracy)

marks7389
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Re: Backend on Pi 4

Post by marks7389 » Wed Apr 21, 2021 10:34 pm

I'm struggling to work out how to force the front end to display in a particular mode, specifically 1920x1080@50Hz. I think I finally understand why making changes in /boot/config.txt is having no affect. I'm not using a desktop (just mythtv lite on Raspbian lite) - do I need to edit xorg.conf or similar to stop it simply picking the highest available resolution from the EDID data?

marks7389
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Re: Backend on Pi 4

Post by marks7389 » Thu Apr 22, 2021 6:41 pm

marks7389 wrote:
Wed Apr 21, 2021 10:34 pm
I'm struggling to work out how to force the front end to display in a particular mode, specifically 1920x1080@50Hz. I think I finally understand why making changes in /boot/config.txt is having no affect. I'm not using a desktop (just mythtv lite on Raspbian lite) - do I need to edit xorg.conf or similar to stop it simply picking the highest available resolution from the EDID data?
I think I've got to the bottom of what was happening, which seems to be down to whether the Pi 4 uses /dev/dri/card0 or /dev/dri/card1.

More information in the relevant thread - viewtopic.php?f=46&t=3937&p=21760#p21760

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