Colossus 2 Audio issue

[artmetz]

I have a Hauppauge Colossus 2 connected via HDMI to an older dish receiver. Recently I've noticed there is no audio sometimes when I watch a channel, however if I exit back to the guide and watch the channel again, the audio is now working.
Recordings sometime have no audio either. My OTA recordings via a Hauppauge WinTV 885 have no issues.
I've replaced the HDMI cable to rule that out. Now I'm at a loss. I don't recall any recent system changes (Windows 7 Ultimate).
From the log I can see that the first attempt uses the AAC decoder, then the second successful try uses the AC3 decoder.
I've attached a screenshot of the decoder settings.

The relevant bits of the log:
No audio:
2021-01-16 11:16:18.094 [DEBUG][1] StartLiveTV@1 (CNNHD)
...
2021-01-16 11:16:27.445 [DEBUG][1] [AAC]
2021-01-16 11:16:27.445 [DEBUG][1] Adding system AAC decoder
...
2021-01-16 11:16:27.507 [DEBUG][1] Audio is mapped on 'AAC' pin
...
2021-01-16 11:16:28.057 [DEBUG][1] Graph filter list:
2021-01-16 11:16:28.058 [DEBUG][1] - AAC Audio Renderer
2021-01-16 11:16:28.058 [DEBUG][1] - NPVR CC Dump
2021-01-16 11:16:28.058 [DEBUG][1] - EVR Renderer
2021-01-16 11:16:28.058 [DEBUG][1] - MainConcept AAC Decoder


Audio:
2021-01-16 11:16:40.824 [DEBUG][1] StartLiveTV@1 (CNNHD)
...
2021-01-16 11:16:45.589 [DEBUG][1] [AC3]
2021-01-16 11:16:45.589 [DEBUG][1] Adding system AC3 decoder
...
2021-01-16 11:16:45.612 [DEBUG][1] Audio is mapped on 'AC3' pin
...
2021-01-16 11:16:46.146 [DEBUG][1] Graph filter list:
2021-01-16 11:16:46.146 [DEBUG][1] - AC3 Audio Renderer
2021-01-16 11:16:46.146 [DEBUG][1] - NPVR CC Dump
2021-01-16 11:16:46.146 [DEBUG][1] - EVR Renderer
2021-01-16 11:16:46.146 [DEBUG][1] - Hauppauge AC3 Decoder



  NPVR.zip (Size: 22.79 KB / Downloads: 0)

[mvallevand]

The best solution is simply to use the recommended LAV 32bit decoders.

Martin

[artmetz]

Thanks. For AAC only or AC3 also?

[mvallevand]

It wouldn't hurt to try it with everything.

Martin

[sub]

You might need to configure the set top box to always output the same audio format (ie, PCM so that all channels are encoded to AAC audio). Otherwise you're probably getting issues with the device resetting the clock when changing between changes between a channel with AC3 vs AAC.

[artmetz]

Thanks. It's an old dish receiver that has been reliable for years, but I'll keep that in mind (I don't recall any settings for audio format however). For the moment I've set AAC to use the LAV decoder and added a 3 second delay after changing the channel with the USBUirt to give the signal a chance to settle in. So far I haven't reproduced the issue.

[artmetz]

Here's an update.
I've been testing a modified USBUirt with a 1, 2 and 3 second delay after tuning the channel and before returning to NPVR. 1 and 2 seconds still had issues (but fewer), 3 seconds failed once with the audio during a week of testing.
(This is based on my assumption the audio needs more time for detection)
As of today, I've started testing the PreferAC3 registry setting and the 3 second delay.

I did a quick test of the LAV decoder and had the same issues. So I backed off that and will test it later if necessary. I see there are some settings I probably need to enable.
My goal is to test one piece at a time and isolate what is necessary for a reliable fix. I should be able to rule more settings in/out over the weekend.

In the meantime, I found the set top box settings and have attached a screen shot of the settings. Should I try "PCM Only"?

[sub]

Yeah I’d try pcm. It’ll like cause it to always use aac audio.

[artmetz]

As an FYI for anyone else that may run into a similar issue:
I've tested the PCM only setting on my Dish 301 receiver for a week now with no audio issues. So I'm concluding that it is now fixed. I don't know why the problem suddenly appeared, unless there was a firmware update for the STB (it's old however).
Prior to that, I did briefly test the PreferAC3 reg setting. It also appeared to fix the issue, but I did not test it long enough to reach that conclusion.
Adding a 3 second delay to the USBUirt code did help, but did not fix the issue 100%. I'd rather have the channel change occur faster anyway, so I dropped that change.
I did not try the LAV Filter or it's AC3 settings. (I hate messing with the decoders <g>)

[shspvr]

As an FYI for anyone else that may run into a similar issue:
I've tested the PCM only setting on my Dish 301 receiver for a week now with no audio issues. So I'm concluding that it is now fixed. I don't know why the problem suddenly appeared, unless there was a firmware update for the STB (it's old however).
Prior to that, I did briefly test the PreferAC3 reg setting. It also appeared to fix the issue, but I did not test it long enough to reach that conclusion.
Adding a 3 second delay to the USBUirt code did help, but did not fix the issue 100%. I'd rather have the channel change occur faster anyway, so I dropped that change.
I did not try the LAV Filter or it's AC3 settings. (I hate messing with the decoders <g>)

As sub said you should used PCM only with AAC that give you best over all audio in long