Rewind and fast forward often freeze or do not work properly

zetoune · February 14, 2021, 4:44pm

Hi there.

I have some issues with RW/FF.
Channels is configured to rewind 7 seconds and fast-forward 30 seconds.

When I press FF (or RW) on my remote, it hangs there for few seconds then jumps further I wanted.
For example, if I want to FF 2 minutes, it hangs at the first minute (for approx a second) and jump to the 3rd minute. I have to press RW to go back at the minute I wanted, but the same behaviour happens, so it brings me back further I wanted. I have to do it again. Eventually, I manage to arrive the moment I want, but it takes several back and forth to succeed. Really annoying

Other behaviour I have then I press RW (once quickly), I see the loading wheel, but it just stays where it is, it replays the same moment over and over. I have to press the button longer but it goes further than the 7 seconds I wanted.

I don't use the AppleTV remote but an Harmony 700 (to control TV, amplifier and AppleTV).
It happens with DirectionRight/Left or FastForward/Rewind.

Server: 2021.02.04.1931
Client: 4.4.0
Both server and AppleTV are wired with Gigabit lan.

Any ideas how I can fix it?

tmm1 · February 14, 2021, 5:23pm

Which Apple TV model? Can you run a speed test between the dvr and TV?

https://getchannels.com/docs/getting-started/faqs/channels-apps/#how-can-i-test-the-network-speed-at-my-tv

zetoune · February 14, 2021, 7:07pm

AppleTV: 4th gen.
Speed: 76.81: Mbit/s
Latency: 4.17 ms
Jitter: 0.46 ms

Wow, it's bad... speed looks like FastEthernet lan, not gigabit, but 76.81 Mbit/s should fast enough to serve video from the server.
The latency is really high for local network, isn't it?

EDIT: I always thought the ATV4 had a Gigabit port but it seems to be a 10/100 Mbits.

Macnbaish · February 16, 2021, 2:53am

Yea, that latency is high and the bandwidth is lower than we would expect. What device are you running the server software on? Are the server and ATV4 plugged into the same gigabit switch?

zetoune · February 16, 2021, 4:21am

What should the expected speed and latency be?
76 Mbit/s is not that low for a FastEthernet port.

The server is:
HP ProDesk 600 G2 with Ubuntu 20.04
CPU: i7-6700T
RAM: 32 GB

Yes, the server, the ATV4 (and the HDHomeRun) are all connected into the same switch

chDVRuser · February 16, 2021, 4:34am

I tried the Channels speedtest between my PC and NAS running Channels DVR.
They're both wired to the same gigabit switch.
I usually run it three times.

Download Latency Jitter
797 Mbs  3.59ms  20.77ms
835 Mbs  1.83ms   2.91ms
805 Mbs  1.37ms   0.96ms

Macnbaish · February 16, 2021, 4:31pm

I would expect to see closer to 100, and 4ms latency between two devices on the same switch is puzzling. Are you sure this device is an actual switch and not a hub? Do you have a spare switch you could replace it with and see if the performance improves?

zetoune · February 16, 2021, 5:30pm

Yes it's a switch (Unifi 16-150W)
When I ping my router from my laptop (connected to the same switch), the latency is around 0.6 ms.
When I ping the server from my laptop, the latency is also around 0.6 ms
When I ping my laptop from the server, latency is around 0.3 ms
Running the speedtest between my laptop and the server (http://server.ip:8900/speedtest)

Download	Latency	Jitter
990 Mbit/s	0.97 ms	0.35ms

Next test is to try with the laptop at the ATV4 location with the same ethernet cable.

tmm1 · February 16, 2021, 9:23pm

Seek speed is directly related to available bandwidth. With gigabit links you will see a 10x improvement in seek speed. For the old ATV4s, it might be better to connect over wifi so you're not limited to 100mbit.

AeroR1 · February 16, 2021, 10:07pm

I don’t know about the OP but I see this behavior in the buffer also. Not just watching a recording.

In the buffer, wifi or Ethernet should not matter if you’re trying to trick play buffered live tv.

zetoune · February 18, 2021, 4:59pm

It seems that the problem does not come from my network performance (even if it does not help for sure).
For the last two days I've used my TV remote (instead of my harmony) I haven't faced the issue so far.
My theory is:

my TV sends commands to ATV4 through HDMI-CEC
The harmony sends commands to ATV4 through IR signals.
The IR signal may be too fast (or too slow), so the ATV4 does not react properly.

Does it make sense?

Unfortunately, when I use my harmony in TV mode, the direction keys do not respond on the ATV4. Either I'm wrong (i.e., the TV does not use HDMI-CEC to drive the ATV4) or the harmony does not work correctly with Samsung HDMI-CEC.