Downmix 5.1 to Stereo

[Brox]

1. I have PMS feeding two PS3's. The first is in my theater with full surround sound. The second is in my family room attached to a Samsung LN46C630 TV with no external speakers.
2. My source is a .m2ts file with ONLY a 5.1 audio file

The source plays wonderfully in my theater, no problems there. However, when I play it through my Samsung TV the audio is horrible. I only hear the "surround channels" so there is virtually no audible dialogue. I'm assuming the 5.1 audio is being passed directly to the TV which of course cannot reproduce 5.1 with 2 speakers.

I would think the audio would be "downmixed" at some point from 5.1 to 2.0 either through the PS3 or TV.

I've played with all the settings on the PS3 and my TV to no avail. Am I missing something? Is it possible for the PS3 or TV to downmix the audio to 2.0?

Any help would be appreciated, if nothing else I guess I could install a 5.1 system on that TV but I'm trying to avoid that cost.

[meskibob]

You've gone through the audio output settings on the PS3 and unselected all of the non-2ch options?

[Brox]

Yes. I've tried about every scenario possible in the PS3 audio output settings.

Currently I have only the default Linear PCM 2 Channel 44.1 and 48kHz selected. The problem still persists.

[meskibob]

What kind of audio in the file? Is it LPCM? It looks like the PS3 might not downmix LPCM streams correctly - http://community.us.playstation.com/t5/ ... p/20987312
Unfortunately the only way PMS will help with this is if you remux/transcode, in which case you can take advantage of PMS downmixing. Your best bet (if you don't want to remux/transcode with PMS) might be to just reencode the audio outside of PMS.

[Brox]

I think you might be onto it. The audio according to eac3to.exe is:

RAW\PCM 5.1 channels, 24 bits, 48 kHz

Hmm. I try not to use PMS to transcode but I'll give that a shot tonight. Thanks for the guidance!

[Brox]

Transcoding worked! Thanks for the advice.

[Brox]

Well, the transcoding option has a problem. It will start the movie just fine but after 10-20 minutes it will develop a lip sync problem, very hard to watch.

I have been encoding my files to PCM but I can use AC3 instead. I've tested this and it works, PMS can play the files just fine and it will decode from 5.1 to 2.0.

My question is how much sound quality do I lose by using AC3 vs PCM? On one movie the PCM file is 7GB and the AC3 file is 700KB, big difference. I know that AC3 is compressed, I just don't know how this compression effects sound quality. Just to note, the ORIGINAL file is TrueHD/AC3, so maybe converting it to PCM doesn't help in the first place. Any ideas??

[meskibob]

Unfortunately certain files can have aysnc problems when transcoded, some of which can be fixed with normal settings or expert settings in PMS, and others not. If you need assistance figuring out what to do with a specific file, follow the Problem Reporting Guidelines. Unfortunately fixing asynchronous playback is not my area of expertise, so you'll need a dev or another forum member to assist you.

As for the sound quality, yes it makes a difference, but there are plenty of other factors at play too (receiver quality, speaker quality, room dynamics, personal hearing, etc). It's a fairly subjective thing that you'll need to determine for yourself. Why not reencode a video, and then do a blind test to see if you can pick the difference between the source and the reencode?

[Brox]

Thanks for the quick reply. I was going to do just that. I suppose I could also encode the file with AC3 and PCM at the same time and let each PS3 pull the "best" audio, AC3 for 2 channel(upstairs TV) and PCM for 5.1(theater room).