Sync Issues - Video Way Behind Audio

With both of my 4th Gen Quads, occasionally a recording is unwatchable because the video is 10-20 seconds behind the audio. Here’s an example: TabloSynchIssues_240328a.mp4 - Google Drive

My voiceover is in the left stereo channel, and the recording is in the right stereo channel. (Sorry if my voiceover sounds a little drunk. It’s because my headset is feeding back my own voice with a slight delay, which causes me to slow down.)

I’ve noticed it mostly with national broadcasts immediately following local ones, so purely speculating here, maybe there’s a broadcasting codec change that Tablo can’t handle.

What it forces me to do is set my phone alarm to just before critical recordings, so if they’re out of sync, I can stop and restart the recording to get a watchable recording.

Note: This sync issue is not unique to my viewing device (e.g., Roku, phone or tablet). It’s definitely a DVR issue, not a viewing device issue.

I’m so unhappy with Tablo that I’m now in the process of ordering an AirTV Anywhere to replace my two Quads. Advice welcomed. Thanks.

@TabloTV @TabloEngineering @TabloSupport

Does this issue happen with completed recordings, or just the ones you try to watch while in progress?

Both.

If it’s the same station, you could try deleting it, rescanning, and re-adding it. This would give your system a full refresh of that channel. This has been known to fix a few things, but IDK if it will for this…

It happens to that station about 80% of the time, but other stations as well. Happened on the 4th Gen Quad I bought in February and scanned right afterwards. Also happens on the 4th Gen Quad I bought Saturday to replace it, and scanned right afterwards. So two scans, two months apart give the same symptoms.

Using a 3rd Gen HDMI connected 2 tuner. I have problems with our Fox station. When we record or watch live nationally broadcast shows, we get random glitches where the video and audio will freeze for a fraction of a second. Sometimes a recording will have complete video/audio desync, making it unwatchable. I have to use Tablo Ripper to offload the show to my computer. If I use Mediainfo on the file it shows the video being 1 hour long but the audio only 50 something minutes. When I extract the audio using an ffmpeg based program, the audio magically has the correct duration. I replace the short audio in the file with the new audio and put the file on my NAS for watching. The random glitches do not happen in locally produced shows, only nationally broadcast shows. The glitches happen when watching the live shows on my Sony TVs tuners, both ATSC 1 and 3. The conclusion is that there is a flaw in the OTA broadcast on this channel that can cause problems with recordings and watching live. It’s the only station with this problem.

Sync issues (again): New 4th Gen Quad. No more FAILED recordings, but the occasional sync issue continues to plague it. Happens mostly on one channel, but also sometimes others.

Jimmy Kimmel recorded just fine, but the Nightline recording immediately following was out of sync. Audio was perfect, but video was behind, making it unwatchable (listenable, but not watchable).

Started out close, but by the end of this clip, the video was 23 seconds behind the audio.
Same results when viewing on phone or tablet. The problem is with the DVR, not the playback device.

Glad my AirTV Anywhere will be arriving on Monday.

@TabloTV @TabloEngineering @TabloSupport

+1

Everyday I record my local ABC affiliate morning news. Then immediately after record Good Morning America.

Sometimes it works perfectly, it records the entire 2 hour show, then afterwards processes it and creates FF/RWD thumbnails.

Sometimes I am able to start watching the recording before it completes. Of those times, sometimes there’s an “audio decode error” with retry or cancel. Cancel just exits the show, and retry just plays the exact same second that failed before, to fail again. But, if I hit retry then fast forward quick enough, I can get it to skip 20-40 seconds past the “error” and it will play the remainder of the show without issues.

Today, I didn’t begin watching until after the recording had completed & thumbnails generated. Within the first few seconds of the recording the video paused/played slowly, while the audio continued. From that point on the audio was ahead of the video. Letting it play after 3~4 minutes the audio cuts out completely and never returns.

My current theory is there’s a minor signal interruption or error that Tablo can’t figure out how to recover from. Then the thumbnail reprocessing makes it worse.

@Egon Do you have recordings saved on your hard drive that exhibit this issue?

@TabloTV

I use a 4th Gen 4 tuner model with a Seagate Portable 2TB External Hard Drive - So all recordings go to the hard drive.

I have not deleted today’s failed recording.

@Egon If you’re willing, we’d like you to put your Tablo in remote access mode so we can extract that recording. Is it today’s Good Morning America?

@TabloTV

Yes, today’s episode

OK thanks! I’ll have support send you an email with instructions.

@TabloTV

Email received

Remote access mode activated

Email replied to including pic of bottom label for MAC/Serial number

Excellent. Thanks!

@Egon are you in the greater Houston area, by any chance? The sync issues I experience affects multiple channels, but plagues KTRK ABC 13.1 more than all the others combined. Just curious. Thanks.

No, I’m in the Toledo Ohio market, but my ABC affiliate (WTVG) is also 13.1 (Display & RF both 13)

Posting what @Egon’s and other examples have helped us learn for the info of others.

We have determined that the A/V sync is directly linked to corruption from poor signal within the broadcast stream.

This is why it tends to happen on specific channels.

When reception quality is on the hairy edge, you can get some playback/recordings that are fine and playable. However, there’s a tipping point at which the broadcast errors pile up and cause difficulty with decoding which can push the audio and video out of sync.

Improving your antenna setup (either in terms of placement or antenna style/type) is often the best plan of attack to avoid this issue.

In much rarer cases, your antenna could be sending too strong (instead of too weak) of a signal, in which case disabling Tablo’s in-line amplifier in the SETTINGS screen is a good first step.

Nope. Cop out. I have a pristine signal on that channel.

I always must set important recordings to start 10 minutes early. Then my phone alarm reminds me to check the recording during those 10 minutes, so I can stop and restart the recording if necessary before the show actually starts. If I’m not home, then I’m SOL.

The signal is perfect. Not a single pixel out of place on ANY recordings on that channel.

Next time it happens, I’d be happy to let @TabloTV log into my DVR to examine it. But don’t blame the signal. The signal is perfect. The problem is the DVR.

@TabloTV @TabloEngineering @TabloSupport

Congratulations! You are probably the only person in the world that has a perfect OTA signal 100% of time.

Unfortunately, the rest of us in the world have signals that vary from moment to moment. Just because you have a good signal when you do a channel scan, doesn’t mean that it won’t vary depending on atmospheric conditions, trees, aircraft, large trucks, ham radio operators, etc, etc, etc.

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