[mythtv-users] Scrambled recordings

[John Nissley]

I have two antenna inputs; one comes to a Hauppauge HD HomeRun and the
other to a Hauppauge HD-1600.  Both work great when I use live TV
("Watch TV" selection from the menu).  Both are scrambled when they are
doing a scheduled recording.  Here are some examples:

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I had a very similar problem I worked through a few months back because what I see in the pictures looks like artifacts in the recording. I really thought that the issue was hard drive related or hardware related but it ended up being errors on a nic and overloading the nic bandwidth with commercial flagging from another device.  I would have 5 or 6 recordings happening some times and you only have two inputs so nic bandwidth is probably not your issue.
I have no idea what your setup really is.  Do you have multiple front ends or one front end back end combo box but it really does not make a difference since my suggestions are generic.

1) Check to see if your bad recordings are mostly from one source. If you are running a recent version of mythbackend it is in the database. If not just check the recordings before hand to see what device they are scheduled on and write it down somewhere.
2) Check your NIC card(s) for errors with an ifconfig -a. NIC errors really messes up HDHR recordings.
3) liveTV and recordings normally have different recording groups and file system locations. Make sure the hard drive the recordings are going to is not going bad. This information is available in the backend setup screens.
4) I assume that your recordings normally happen at night so you may want to verify signal strength at night because it may be different since I noticed that you are using an antenna.  The HDHR has a nice windows app that can give you that information or when you start live tv that information normally shows at the bottom of the screen as the channel is being set up.
5) I also assume that you have some kind of hub or switch that ties your network together.  If it is a hub you may have collision problems from other ports.  The HDHR is UDP so any packet dropped is not re-transmitted.  Even if it is a switch try moving to another port.  This is a hail marry but it is worth a shot if all else fails.

Good luck, this type of thing drove me crazy for a few weeks and got me a lot of funny looks from my wife until I sat down and trouble shot the problem piece by piece.  You can also check your interface utilization with the iftop command.  iftop is not normally installed by default so you may need to install the iftop command line tool on your system.