Drop out at start of recording

[csadoian 36]

I've had an issue recording programs that has been occurring for some time now that I've been trying to track down.

 

What is happening is that, at the start of a recording the TV signal will appear to "drop out" momentarily, like I have a weak signal from my antenna.  If I am lucky, the dropout will only distort the recording for about 3-5 seconds, and then everything is fine after that.  However, there have been a few cases lately where the dropout caused the audio and video of the recording to become un-synchronized, with the audio several seconds ahead of the video (sometimes MANY seconds ahead of the video, like 20 seconds, which makes the recording impossible to watch).  There was even one occasion the dropout caused the video to stop (i.e. black screen) but the audio continued for the entire length of the program.   My recordings are being transcoded to MKV format, so I'm guessing when this "dropout" happens it messes with ffmpeg and the resulting recording becomes damaged.

 

Anyway, since the cause of this appears to be signal drop out, I first suspected my antenna, but I have monitored the signal on a TV that is directly connected to my antenna system and it is always perfect.  It is not limited to a particular channel, it happens on all channels.  It also does not happen all the time, but it does almost ALWAYS happen just as the recording starts (withing a second or two).

 

I have 3 HDHomerun tuners in my setup ... CONNECT, EXTEND and PRIME.  I have not noticed this happening on my PRIME tuner, but I don't record much on that lately.  Almost all my recordings are OTA, and since my CONNECT has the first IP address it was the first tuner to be used.  So I suspected the CONNECT might have a problem,so the other day I switched IP addresses and made my EXTEND first in line.  Didn't make a difference at all. Still got the dropout at the beginning of the recording.

 

I am using Hardware acceleration (Nvidia), so I am going to turn that off today and see what happens.

 

I am going to attach some logs of the last time it happened, which was on 04/04/18 at 17:30, when Emby records World News Tonight on my local ABC station.  The tuner used was the EXTEND.  This was followed by a recording on the same channel of my local news at 18:00, which did not have the "dropout".

 

 

server-63658441415.txt

record-transcode-4c9617e5-8d8b-49c8-9d98-3a2aefeee56a.txt

record-transcode-f21c2bd7-5e08-4096-8627-08e684db41f1.txt

[Luke 42085]

Hi, please try turning off the conversion feature and let us know if the issue persists. On the next release this feature will be gone anyway and replaced by a feature to convert after the recording has completed. Thanks.

[csadoian 36]

Ok, I will try that, also.  I am in the process of doing some test recordings with hardware acceleration turned off, to see if that makes any difference.

[Luke 42085]

Thanks for the feedback.

[csadoian 36]

FYI, no difference with hardware acceleration turned off, so I turned it back on.

 

I am running another test, this time substituting the latest release version of ffmpeg (3.4.2) for the one that comes with Emby (identifies itself as version N-83781-g3016e91).  I have emby set to do 3 recordings, so far one has started and there was no "dropout".  We'll see what the others show.

 

I know you said the real time conversion is going away in the next release, so I'm just doing these tests to satisfy my curiosity. 

[csadoian 36]

Another FYI,

 

After making the change to ffmpeg Emby recorded 3 test recordings without dropouts.  Later in the evening it did 4 more scheduled recordings and still no dropouts.

 

So changing to v 3.4.2 (64 bit) of ffmpeg did seem to make a difference.