[alsa-devel] Audio Mini Conference Minutes - Edinburgh 21st October 2013

[Anssi Hannula]

21.11.2013 20:22, Mark Brown kirjoitti:
> On Mon, Nov 18, 2013 at 05:35:42PM +0000, Liam Girdwood wrote:
>> On Sat, 2013-11-16 at 17:01 +0800, Wang Xingchao wrote:
> 
>>>> We could use offload, on roadmap for Hires audio on android PCM,
>>>> maybe float instead of 24 bit. Need for 192kHz, Probably not use effects.
> 
>>> Does android support HBR audio now? As i know from Dolby guys, no
>>> customers in Android area are buying Dolby TrueHD license, so i guess
>>> the answer is NO. Most of the customers are from AV receivers and
>>> BlueRay players.
> 
>> Afaik, no one is using high Bit rate audio atm, but there is increasing
>> interest amongst Android OEMs.
> 
> There's a few things shipped doing 192kHz/24 bit - the LG G2 was one of
> the first IIRC.

At least Wang Xingchao seems to be talking specifically about HBR in
relation to HDMI specification, i.e. compressed audio, not PCM...

HBR audio is the way high-bitrate (over 6.144Mbps) compressed IEC 61937
streams are bitstreamed through HDMI. The only such formats supported by
IEC 61937 are DTS-HD MA and Dolby TrueHD (MAT), used on e.g. Blu-ray discs.

The only in-tree ALSA driver supporting HDMI HBR is HDA, AFAICS.

>> Most of the x86 and ARM HW will support HBR audio over ASoC PCM DAIs and
>> HDA, but I'm not sure about which HDMI audio devices support HBR in HW
>> atm...
> 
> It should be relatively common I suppose given that video sources have
> tended to use HBR for a long time (even DVDs do it as standard), though
> it's possible the mobile
> chipsets are limited in some way.

Video DVDs only do PCM, AC-3, DTS and MP2.

-- 
-- 
Anssi Hannula