From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: Direct Stream Digital (DSD/DST, One Bit Audio) HDMI pass-trough Date: Tue, 14 Oct 2014 09:43:42 -0500 Message-ID: <543D369E.5020002@linux.intel.com> References: <543C58AC.9000701@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by alsa0.perex.cz (Postfix) with ESMTP id 8D87C2606AD for ; Tue, 14 Oct 2014 16:43:48 +0200 (CEST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Andrej Falout Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On 10/13/14, 7:49 PM, Andrej Falout wrote: > On Tue, Oct 14, 2014 at 11:56 AM, Pierre-Louis Bossart > > wrote: > > On 10/11/14, 1:33 AM, Andrej Falout wrote: > > Hello, > <...snip...> > 5. Note that as far as I know, no proprietary drivers on > Windows > (ATI/AMD, Nvidia, Intel) support this; It will be the first > time a device > that is not a SACD player outputs DSD over HDMI, on any OS. > I am assuming > that this has nothing to do with hardware limitations of > the HDMI chips > used for video outputs (I could not find any reference for > such assumption > in any HDMI chips I examined specs for). Therefore, I > assume that > implementing this has no hardware prerequisites. > > > HDMI controllers typically don't support DSD in the PC space. It'd > be easier to convert to high-res PCM (HBR). > > > Hello Pierre-Louis, > > Thank you for your comment. > > What are you basing your assessment that "HDMI controllers typically > don't support DSD in the PC space"? I looked, but could not find any > evidence for this. I am basing my judgement on first-hand experience with silicon. > Certainly, DSD is not a part of HDMI hardware implementation (such as > for example, CEC). From all info I have, DSD is simply multiplexed into > HDMI data stream, just as DST-HD or AC3 is. This multiplexing is typically not implemented - mainly because this isn't a format used outside of niche markets and there was no real format to convey DSD over PCM frames until the DOP format was created in 2012. DTS-HD and AC3 use a PCM format which is rather straightforward to implement but there's quite a few cases where these modes have been dropped. HDMI only requires 48kHz 2ch really. Note that the facts don't mean any negative judgement on quality, i was at AES this week-end where I heard outstanding DSD/DXD recordings. You will have more luck with a USB DAC, there are multiple USB DSD products available. > > The goal here is to have a native DSD transport, so conversion to PCM is > not an option. > > Thanks, > Andrej Falout >