Hi Anssi,
I think the One-Bit Audio and DST formats are just misnamed here and
can't be carried over IEC 61937 (ATRAC can be) - the IEC 61937 specification does not cover One-Bit Audio or DST.
Does it have to be? Given that it is defined in CEA 861, and that 61937-1 makes specific provisions for non-PCM data:
Page 16:
"In cases where the interface is used to convey non-linear PCM audio bitstreams..."
I think the "third-party solution" refers to a driver implementing support for a non-HDA-spec HW feature which allows One-Bit audio / DST / raw packets to be transmitted (in a similar way "EPT" (Encoded Packet Type field in Pin Widget Control 7.3.3.13) allows setting HBR or ASP packet transmission).
Why would an "HW feature" be required to "allows One-Bit audio / DST / raw packets to be transmitted"?
What would such "HW feature" do? What could it possibly do?
Thanks, Andrej Falout
Thanks, Andrej Falout
On Mon, Jan 5, 2015 at 4:46 PM, Anssi Hannula <anssi.hannula@iki.fi mailto:anssi.hannula@iki.fi> wrote:
04.01.2015, 05:10, Xuebing Wang kirjoitti: > Anssi, Libin, > > Thanks for your help. > > After a little bit of research, I do think it is possible tostream DSD
> over HDMI (the mechanism is as Anssi mentioned, similar way asHBR).
> > Please see HDA spec: > 3.7.1 Stream Format Structure > (If the TYPE is set to Non-PCM, the controller just pushes dataover the
> link and is not concerned > with formatting. The base rate, data type, and number of Words(MULT) to
> send each valid frame > are specified to control the rate at which the non-PCM data issent.)
> > 7.3.3.8 Converter Format > > What do you think? In order to implement this similiar mechanism > (similar to HBR), I still have some detailed questions that I willwrite
> in another email. Thanks. That setting will still not allow you to send One-bit audio or DST packets. The stream will still be encapsulated in either ASP or HBR packets, depending on the value of the EPT field (Encoded PacketType,
7.3.3.13). > > On Thu, 2015-01-01 at 06:37 +0200, Anssi Hannula wrote: >> 01.01.2015, 04:07, Yang, Libin kirjoitti: >>> Hi, >>> >>>> -----Original Message----- >>>> From: Anssi Hannula [mailto:anssi.hannula@iki.fi <mailto:anssi.hannula@iki.fi>] >>>> Sent: Wednesday, December 31, 2014 11:45 PM >>>> To: Xuebing Wang >>>> Cc: Yang, Libin; alsa-devel@alsa-project.org <mailto:alsa-devel@alsa-project.org>; Lin, Mengdong; ; TakashiIwai; ;
>>>> Wu Fengguang >>>> Subject: Re: [alsa-devel] DSD over HDMI: audio datapacketization
>>>> >>>> 31.12.2014, 17:38, Xuebing Wang kirjoitti: >>>>> Anssi, Libin, >>>>> >>>>> Thank you very much for your help. >>>>> >>>>> If L-PCM audio data packetization is done by hardware, is it possible >>>>> to implement DSD over HDMI on Intel integrated graphics? Thanks again. >>>> >>>> I don't think so, unless: >>>> >>>> (a) It is possible to somehow encapsulate the stream in Audio Sample >>>> Packets and be accepted by the receiver (like e.g. AC3, DTS). I'm not aware of >>>> such a way. >>>> >>>> or: >>>> (b) There is some undocumented feature in the Intel HDMI codecs allowing >>>> the driver to switch to DSD or driver-constructed packets (instead of >>>> ASP) in similar way as there is a way to switch to HBR packets. >>>> >>> >>> Yes, I agree. And I'm not sure whether HDMI spec supports DSD. >> >> It does, via the "One Bit Audio" and "DST" formats (spec 5.3.9, 5.3.10 >> in 1.3a/1.4a). > > -- Anssi Hannula-- Anssi Hannula