Hi Anssi Hannula ，
2013/11/22 Anssi Hannula anssi.hannula@iki.fi:
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.
I think that depends on vendor's HDMI controller, not only the HDMI Specification version. And HDA seems the first one claims supporting HBR, i donot see any other ARM based Soc has such claim.
Lots of HD video sources are using HBR audio, and lots of set-top boxes/TV(ARM based) have the requirements to paly HBR audio in HDMI passthrough mode. Currently the solution is from vendor specific, they downmix HBR audio into 5.1 or Stereo.
thanks --xingchao
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