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Re: Sound 5.1

Posted: Thu Oct 27, 2011 9:13 am
by hanysl
Will Raspberry Pi have 5.1 sound or stereo ??

Re: Sound 5.1

Posted: Thu Oct 27, 2011 4:28 pm
by Montekuri
I think you can get 5.1 sound from the HDMI conector.
There is also a 3.5mm jack that is just stereo.

Re: Sound 5.1

Posted: Thu Oct 27, 2011 9:14 pm
by hanysl
HDMI is for 5.1 . But I donĀ“t know if Rasbi will decode 5.1. sound

Re: Sound 5.1

Posted: Thu Oct 27, 2011 9:30 pm
by liz
I have a *lot* to say about the price Dolby demands for licences, which will be going into a blog post later on when we've finalised all the codec licences for the board. In short, the licence we have to buy for Dolby 5.1 takes up 4% of the $25 cost of the board, which seems absolutely obscene when you consider everything else that makes up the other 96%. (Hardware prices have been really manageable, and h.264, which does a hell of a lot more, costs a hell of a lot less - the licence for 5.1 was a real stand-out in terms of price.) It's a racket, and it's particularly infuriating because we know that a lot of our audience won't find the device usable without it.

I can't confirm yet whether or not it'll be on all the devices - we may go so far as to have two separate options you can buy, one with 5.1 and one without, calling out the cost as we go. Whatever we end up doing, I do want to draw attention to just how much of the cost of a unit is sunk in licensing fees. Pretty much all of the hardware manufacturers we've dealt with have been extremely cool, have given us discounts because they want to support what the charity's doing, and have been very easy to work with. Not so the codec licensing guys, who have been absolutely immovable.

Re: Sound 5.1

Posted: Thu Oct 27, 2011 9:43 pm
by gbl08ma
If only those things like Dolby could be implemented as open source without paying for licences... at least, you don't have to pay for the good old stereo sound. Damned patents!

Re: Sound 5.1

Posted: Sat Nov 12, 2011 3:32 am
by kendrick
liz this goes beyond the intent but how possible would it be to turn say a gpio or somthing to optical/rca surround out? this kind of possibility just kinda tickles me...

Re: Sound 5.1

Posted: Sat Nov 12, 2011 3:39 pm
by peregrino
Quote from liz on October 27, 2011, 22:30
Whatever we end up doing, I do want to draw attention to just how much of the cost of a unit is sunk in licensing fees. Pretty much all of the hardware manufacturers we've dealt with have been extremely cool, have given us discounts because they want to support what the charity's doing, and have been very easy to work with. Not so the codec licensing guys, who have been absolutely immovable.

Yeah, that's awful. You said also that a lot of people wouldn't find the device useful without the dolby license, does that imply that without the license we couldn't get any kind of sound if connected by hdmi or just that you would end up without 5.1?

Also about h.264, as the codec of choice for web video is now webm (patent-free, yay!), is there any chance to get webm hardware based decoders instead of h.264? I know there are dedicated chips to decode h.264, but I have no clue about the status of those for webm. Google said they were on the pipeline when they released webm, and that was quite some time ago :)

Re: Sound 5.1

Posted: Sat Nov 12, 2011 11:02 pm
by nullstring
Quote from peregrino on November 12, 2011, 15:39
Yeah, that's awful. You said also that a lot of people wouldn't find the device useful without the dolby license, does that imply that without the license we couldn't get any kind of sound if connected by hdmi or just that you would end up without 5.1?

As far as I understand, the need for Dolby licenses comes from needing to decode the sound to PCM audio.

Basically, in this case, the codecs are needed in order to output analog stereo sound from Dolby audio. (DVD's/Bluray, etc.)

Outputting the Dolby sound through HDMI wouldn't require any codec because it would be transferred as Dolby sound which would than be decoded by the device receiving the audio rather than the RPI.

While we're talking about sound, any word on whether the I2S port is going to be included? There is demand for that, at least from me =)
EDIT: looks like it was just coming out of the GPIO anyway and there is little chance

Re: Sound 5.1

Posted: Sat Nov 12, 2011 11:02 pm
by nullstring
[accidental double post]

Re: Sound 5.1

Posted: Sun Nov 13, 2011 5:46 am
by portets
Quote from peregrino on November 12, 2011, 15:39
Also about h.264, as the codec of choice for web video is now webm (patent-free, yay!), is there any chance to get webm hardware based decoders instead of h.264? I know there are dedicated chips to decode h.264, but I have no clue about the status of those for webm. Google said they were on the pipeline when they released webm, and that was quite some time ago :)

there's some info in this thread:

http://www.raspberrypi.org/for.....#038;t=739

Re: Sound 5.1

Posted: Sun Nov 13, 2011 6:52 am
by david13lt
As I remember in VP8 (WebM) vs. x264 (H.264) encoding speeds were horrifying slow (5-25 times) and it had lower quality (20-30%). It is not suitable for live encoding, i.e. live conferencing. The test were done in 2011 Q1.

I still would support H.264 as it s dominant, fast, high quality, and has dedicated hardware for decoding and encoding. Support for WebM is coming to hardware and other software. Safari and IE does not support WebM and it's up to Google to provide required plugins. So currently the fragmentation in the market is too huge.