AV Sync issue with only one Channel and only when transcoding

Channels Apple TV Troubleshooting
#1

I have a Audio/Video sync issue on ONLY one channel and only when I have transcoding enabled (and it seems any level will cause it, from heavy to mobile to Internet240). The Channel is the OTA ION in the DFW area. I have three HDHR Extends (both original and new model). All of them do it, and they only do it on one channel. If I turn off the transcoder, they run flawless. I have ATVs running both wired and wireless - No difference.

Shows that are recorded (transcoding enabled) have no issues playing back.

I also checked the Beta and GA ATV client, as well as the IOS GA and Beta client. It happens on all of them. It does NOT happen in the web client (which is set for Hardware transcoding).

Any ideas???

#2

The sync issue is resulting from the transcoding built into your Extend.
The hardware transcoding through the web client uses the system where your Channels DVR is running to do the transcoding.

#3

If that were true, (and I just added this as I didn’t share it originally) I would have expected recorded shows to have the same issue. They don’t. Shows recorded with transcoding and played back later are fine.

#4

That setting you are using (heavy, mobile240, etc) is just changing the transcoding setting on your Extend. It is not the same as the web client hardware transcoding, which is using the system hardware where Channels DVR is installed. This is absolutely true.

Your recordings can use an Extend setting, though, if you set it up that way on the DVR web-ui settings.

#5

Correct. And when you setup hardware transcoding for the DVR recordings and have a HDHR Extend it uses the Extend’s native HW transcoding( Or so I understood). So in one case (recording via DVR) it works, in the other case (playing live via ATV or IOS client it doesn’t). I understand the difference with the Web Client, but why it would work for DVR recording and fail for live playback via IOS or ATV client, both cases use the HDHR Extend’s HW transcoding, which is where I am struggling.

Since it is working successfully when I do a DVR recording using the Extend, I don’t know why it wouldn’t work when playing back live…

#6

@maddox @tmm1 - Any thoughts?

#7

Curious if anyone has anyone thoughts on how to resolve this? It only occurs on one channel, it is consistent in that the video becomes a few seconds out of sync with the audio, and only occurs when transcoding is on (any setting), and it only occurs in the IOS and ATV client. It does not occur on the web client. I have three HDHR Extends, both old and new model, and have tried and isolated each of them. It occurs on each of them.

I use the extends and transcoding because all but 2 of my 9 ATVs are wireless. With Transcoding they run perfect except this one channel. If I turn transcoding off for live viewing I will see the streams stop and restart, so definitely worth having it on.

#8

Email me a two minute recording from that channel and I will look

#9

How should I capture that?

#10

Use the DVR to make a recording and then stop it

#11

Assume you want it with transcoding disabled.?

#12

Both would be helpful, but whichever one is causing issues. So transcoding to heavy?

#13

sent both to [email protected]. Let me know when you have it…

#14

@tmm1 Did the email and video samples make it?

#15

Yea I got the email. Will take a look on Monday

#16

Thanks.

#17

Am I understanding this correctly?

  • recording w/ transcode=none: works
  • recording w/ trancode=heavy: works
  • live tv w/ transcode=none: works
  • live tv w/ transcode=heavy: out of sync
#18
  1. Yes
  2. yes
  3. Yes
  4. Yes - This is the issue, but it seems to be at any level of transcode

So all true

#19

Thanks. I was able to reproduce the issue with the samples you sent me. Something weird is going on with the EXTEND transcoder… I think the output it is generating is technically invalid.

Anyway, since recording playback works I think I can make live tv work the same way. Will work on a fix for the next beta build.

#20

Awesome thanks. Look forward to it. Sadly it’s the one channel my wife watches most. (Law & Order 7x 24)

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