My next project includes the multichannel audio input to Beagleboard.
The most promising source of 7.1 24-bit 192 kS/s audio seems to be the
Blue Ray (DVD). All the players seem to have HDMI output either v. 1.3 or v. 1.4
I read the v. 1.3a specification and found out that the multichannel
audio is transmitted
inside "data islands" interleaved with video frames and encoded with
4-to-10 bit scheme.
To separate audio from the HDMI stream using OMAP3530 BSP3 seems to me as a
possible but tedious approach. Has anybody ever tried it?
Another possibility would be to use the HDMI receiver chips from
Silicon Image but their
specifications seem to be reserved "for the big boys only" as is
unfortunately the case with
so many interesting chips (WLAN, 802.11n etc) nowadays. Has anybody
extracting the 7.1 24/192 with these chips? What kind of audio stream
is available? I2S,
SPDIF or AES? What would be the most versatile HDMI receiver/decoder
from the multichannel
audio point of view?
Yet another - and maybe the easiest solution would be an A/V receiver
with several HDMI, SPDIF, AES, and analog inputs and one or more I2S
and SPDIF/AES outputs. Can somebody recommend one? My favorite format,
of course, is I2S since it has such a nice support on OMAP3530.
As you can see I am in the very beginning with this task, so please
lead me to the right track!
Happy Easter to you all,
I think that your big challenge will be HDCP. The Blu-ray player will encode the output with it, and you’ll find that the HDMI receiver chips include HDCP features and preprogrammed keys. This means that you’ll need to be an HDCP licensor and that will probably take things out of the hobbyist domain. The local sales reps for the HDMI chip vendors can get you more details and reference boards, but be prepared for things to get a little pricey.
FWIW, 7.1 audio comes out as 4 I2S streams from the receiver chips. I don’t have any ideas on an off-the-shelf AVR that can output I2S. Sorry.
2010/4/4 Seppo Nikkilä <firstname.lastname@example.org>
Do you know if it is possible to connect external Blue Ray drive to Beagleboard and connect it to TV to watch the movie ?
Can region code be changed in software?
It’s not possible. Blu-ray has mandatory copy protection (see AACS and BD+) that would need to be implemented to get at the content. The copy protection is a bit involved both technically and business-wise to say the list - especially compared to the DVD CSS stuff. Also, I’m pretty sure that the Beagleboard can’t support the AV format requirements of Blu-ray such as the H.264 1080p decode or multiple audio stream decode.
Slightly off topic but your information here is of huge interest to
me. Given the issues around protection of HD content (with HDCP, PAP
etc), I'm wanting to know whether it would be possible to strip out
the audio signals in a bluray machine that is equipped with 7.1
Would it be possible to capture the audio just prior to the bluray
DAC's and feed it out as 8 channels of digital? If it is possible,
what format is it in? Is it I2S?
I need 8 channels of AES/EBU to be fed into my processor from the
bluray. I use an EV netmax N8000.
The ones that I know of output a set of I2S signals to the DACs. I’d look up the datasheet for the DAC on your Blu-ray player, since it is probably a lot easier to get than the one for the main SoC.