AC3Filter Not Upmixing Properly From 5.1 to 7.1ch

[kairukun]

I use AC3Filter on most of my videos with stereo audio channels I have Logitech G430 7.1 surround sound gaming headset, they work fine on upmixing from Stereo to 7.1ch, when I use 5.1ch/6ch audio, it will not fill the side speakers left and right, its like the matrix is not filling them speakers. I'm using DTS, AC3, and AAC-HE. Any Ideas? Is this a flawed in the filter or input/out problem, I already set the output to 7.1 so what am i missing here?

[jagabo]

5.1 doesn't include side speakers so why should upconverting from 5.1 to 7.1 put audio on the side speakers?

[ndjamena]

You need THX Cinema or Dolby Pro Logic IIx (PLIIx) processing for 5.1 to 7.1.

[jagabo]

And then you'll be getting fake crap from the side speakers. Just like you get fake crap from the rear speakers when up-mixing a good stereo track.

[ndjamena]

Yup.

I've just got my system set up to convert everything to stereo then to spread that evenly across the speakers. I never sit in the right spot for 7.1 to be effective anyway, but if he's got a headset and can tell the difference, fake crap is better than nothing.

[jagabo]

fake crap is better than nothing.

No, nothing is better than fake crap.

[ndjamena]

It sounds like he can hear there's something missing. We're talking about a headset here, head phones, so if he can hear there's something wrong then there's something wrong.

Maybe he should clarify.

[kairukun]

Yeah I can tell the difference, ok what's the point of having 7.1 or 8ch headset if you can't use all the channels, the ones that are being used a lot will go bad faster than the one is not being used a lot or not at all! So I guess im not the only ones having trouble, and actually upmixing stereo on a 7.1 is actually better because its more immersive on most musics, plus I add delays on them speaker channels, works even "gooder" lol anyway, It's not crappy, I prefer upmixing the channels to the highest possible channel count, It's like if your audio file is only stereo, it would only use the front speaker, which it doesn't sound very good, and after upmixing it to 7.1, I was like WOW, why didn't I find this filter as soon as i bought my headset. The only thing you have to do is tune your equalizer and the mixing matrix! It was straight forward. Well that sucks so you really can't upmix 5.1 to 7.1 with ac3filter huh? is there alternatives?

[ndjamena]

OK, what I'm thinking is this:

Your AC3 files are labelled as [L C R BL BR LFE] and your player is actually taking that literally and applying them to those channels, even though the AC3 equivalent to BL and BR is in fact SL and SR. Those back channels are in fact SUPPOSED to be the side channels. It's the back channels that are missing, not the side. But because of old AC3 labelling (pre 7.1) the side channels are being routed to the wrong speakers in your headset and of course it sounds wrong because there's a whole section missing in the sound field and things sound like they're happening behind you when they're supposed to be to the side.

Does that sound about right?

[kairukun]

You're right about the speakers are being routed in the wrong place! I mean will it require to encode the 5.1 to 7.1 audio file, and is that why it's not upmixing to 7.1 because my audio files are incompatible to decode? well it is a hypothesis, I'm thinking it might take more CPU power to encode the audio file and put it to 7.1 raw. It will probably available in the future, I hope so, because some movies with 5.1 isn't going to cut it especially with 7.1 or higher channel counts!