MP4 & 5.1 Audio

[mike boss]

I've started to "obtain" some Blu Ray rips that I play via a USB flash drive insterted into my Blu Ray player.
I notice that in most of the write-up's it says the files contain some form of 5.1 audio.
I have a Samsung Wi-Fi Blu Ray player hooked up via HDMI to my TV and for the audio out an optic cable into an old Technics SADX 940. The reciever itself plays 5.1 & DTS audio fine and works well with the Blu Ray and old existing DVD players I have.

On the BR rips I see that I am able to switch audio tracks, sometimes the file itself contains not 1, but 3.
However when switching nothing indicates (on the rip itself) which audio track is which, so I don't know if I have a 2.0 stereo, or a 5.1 .

Either way, no matter which soundtrack I select I don't get 5.1 audio. I know this because my reciever indicates "digital" when playing 5.1 audio.

I'm wondering if putting the files onto a disc would change this ?

Any advice/info ?

[mike boss]

Could it be that the 5.1 audio from an MP4 can only be decoded via HDMI not an optic cable ?

[ahofle]

Is the optical cable going from Blu Ray to receiver or TV to receiver?

[mike boss]

Optical goes from the Blu Ray right into the receiver.
For DVD playback it shows 5.1 digital, I'm yet to test DTS.
In Blu Ray when playing it also shows as DTS (which is how I set it, as the receiver isn't HDMI).
The issue is that via USB I can't seem to get 5.1 audio.
I'm wondering if its a CODEC issue ?

[mike boss]

Somewhat interesting note.
I moved over two files to a data disc, one of the files I know had an AC3 audio file.
When I played the two files my digital receiver did indeed indicate digital (meaning 5.1) for the one file.
However when I went up and listened to the speakers I could hear the dialouge from all the speakers.
Leading me to believe (atleast in that case) all be it 5.1, it might not have been true 5.1 .

The other file did not indicate digital, just prologic, didn't seem to make use very much of any of the speakers other than the center. However the prologic decoding did seem to do a good job of keeping the dialouge just to the center speaker.

I'll now need to test the file with the AC3 from the USB drive to see if it will also indicate digital. I'd also like to try other AC3 files to see if I get the 5.1 I'm used to from a DVD.

[kahlid74]

So this is the wonderful lands of rips.  Not all rips are equal.  It depends on who encoded it and how they encoded it.  They could have encoded it with only 2.1 to save file size and since you're using HDMI, the sound is digital no matter what in the receiver's eyes.  So fully identify if it is a 5.1 Rip or not you need to plug a computer with 5.1 into the receiver and use something like VLC/XViD/DIVX players to watch it.  Otherwise you'll never know if the RIP is or isn't 5.1 since your receiver isn't really a computer and might not be able to decode it.

[mike boss]

Makes sense.
Funny enough, I have a nice HP entertainment serries laptop (model number escapes me now) with HDMI out.
It's not 5.1 but I wonder if that would send the correct 5.1 channel audio out ?
Then again my receiver doesn't have HDMI so I guess it wouldnt matter.

I guess ideal for me would be the ability to enjoy these hi-def rips in full 5.1, but seems I might need some upgrades.

Thanks all