Some recordings corrupted, live playback works fine

Channels DVR Server
#1

Hi, there! I’ve found a few similar threads such as “Corrupted Recordings from DS216+II” back in February but none seem to have a resolution. My problem is also slightly different from those:

Most of my recordings work fine except for specific ones from my local CBS station. For example, The Late Show with Stephen Colbert is always corrupted on disk (macro blocking, sound cuts out or turns to buzzing, etc.) but I’m able to watch live without problems. I occasionally have a similar problem with SNL on NBC but it’s far less frequent. I wonder if the bitrate is higher for those shows and that might be causing problems. One odd thing is that I am able to have a second recording on a different channel running at the same time as The Late Show that I can watch without any issues whereas The Late Show is corrupted.

I’m running the DVR on a Synology DS 916+ with 8GB RAM. The load factor is always around 1.5 or lower and nothing besides the DVR server is running, so most of the CPU, memory and network is idle according to the resource monitor in DSM. Everything’s also connected via ethernet to a Gigabit switch. This issue is present in DVR versions 2018.04.05 and 2018.06.05. I’ve checked the logs and no errors or suspicious messages show up. (When I try to play the problematic recordings through the web UI or on a mobile device, I do see lots of messages about corrupted packets but I assume that’s because the content on disk is bad.) How should I go about diagnosing the issue?

Thanks!

#2

Have you tried to play the recordings directly via VLC or other player to confirm they are corrupted on disk?

Are the HDHR and the NAS plugged into the same physical switch?

#3

Yes, VLC also has the same issues when playing back the video file. Both the HomeRun, NAS and ATV are connected to the same switch.

#4

Pretty strange. What hdhomerun model? Is the firmware up to date?

#5

I have two HDHomeRun EXTENDs both running the latest firmware. The other thing is that I had to turn off tuner sharing because it resulted in being unable to watch the program even in live mode. (Again, not all programs.) So it seems that going to disk is the issue. When I checked the recording file, it’s just over 7GB for 1 hour, so only ~2MB/s.

#6

Also corrupted files while direct viewing is fine. I am running tvos 11.3. I remember reading that the problem showed with 11.3 and was not there on 11.2

#7

I assume you’re recording with the transcoder set to none?

Tuner sharing doesn’t write to disk. If that’s having issues too, that strongly suggests the network link to the NAS is bad.

Do you have one or two Ethernet cables from the NAS to the switch? I would try swapping the cable and using another port.

#8

Ah, I didn’t realize you don’t write to disk. I’ll see if I can find something with the network.

1 Like
#9

Today I experienced the opposite of my original problem: The recording is perfectly fine but the live stream shows the same kinds of problems that recordings had on previous days. I tried pulling the Ethernet cable from the ATV and also turning tuner sharing on/off but none of that improved the playback. But then going back to the recording, the same point in the broadcast plays perfectly.

#10

You can check the hdhomerun tuner status page when having live issues and see what the Signal Quality/Strength is as well as the Streaming Rate.

If it’s a network issue the streaming rate will fluctuate and be much lower than usual.

If it’s a antenna issue then the signal numbers will be low.