The Return of the Bad audio quality through SCART from Genesis – OSSC 1.6

[renovigo]

Hi there,

I just wanted to point that I was using the FW 0.83a through the OSSC, and as I’m mainly using the Megadrive model 1 through it, I noticed the problem described in this previous thread. This is exactly what I encountered.

To resolve it, I had to step back to fw 0.80a. That’s a shame because I found the 0.83a settings quite interesting and useful, but that hissing sound problem was really annoying.

Maybe for an upcoming firmware it could be great to think about the Megadrive/Genesis sound.

Thank you !

[marqs]

Did you test all firmwares between 0.80a and 0.83a? There has been no changes on the audio ADC configuration since 0.80, but another mysterious issue has been reported to pop up in 0.82 that introduced a new soft-CPU which might caused some side effects to I2C delays etc.

[renovigo]

0.81 is fine, I’m using it now, but 0.83 had the issue. Then I decreased to 0.82 to give a test and the problem was still here.

Maybe it would be interesting to know if anyone encountered the problem as well.

So 0.80 and 0.81 = good for MD sound
0.82 and 0.83 = sound issue

[marqs]

Can you update to this test firmware and report the numbers displayed when you press INFO on remote?

[renovigo]

Hi Marqs,

I will test it as soon as possible, and let you know. Thanks for looking into this by the way.

[renovigo]

I just did the test. Still the same issue with MD1 unfortunately.
By pressing INFO I get these numbers displayed like this :
00 00 03 00 30
262p 454727

[marqs]

There was no changes except that debug print. It indicates that at least audio ADC has correct configuration, so the issue is elsewhere. I updated the image with increased I2C and system delays, you might want to re-download it and try if that makes a difference.

[renovigo]

I’ve tested it this morning, and unfortunately no change, I’m sorry. Always the same hiss on bass sounds, exactly as reported on the another thread.

[marqs]

The strange thing is that there are no changes in audio code between 0.81 and 0.82. The problem seem to trigger only on certain boards, otherwise there would have certainly been more similar reports after 0.82 update. I noticed one issue on how audio infoframe is set but it has been there since audio support was introduced. As your audio ADC configuration was correct, I’m starting to wonder if IT6613 somehow ends up being set incorrectly. Could you download this firmware which dumps relevant register values (via INFO again) and post those here?

[renovigo]

Hi,

Thanks for sharing this, but the problem is still here. I understand it’s very strange, but again I’m sure it only happens via the ossc, because when I make a direct connection to an aux in to my amplifier, it’s good.

So here’s what I read when pressing “info” :

00c101e400080000
0800010002db1100

[marqs]

The register values are correct so it seems that HDMI TX is also configured properly. The Infoframe issue mentioned earlier will be fixed on next official fw, but I’m not sure if that helps in your case as the metadata wasn’t properly set even in 0.81.

[renovigo]

Well ok then, I will keep pluging the MD on direct aux in, as the latest fw version are much more improved than the 0.81.
Thanks a lot for having look at this by the way !

[Author]

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