From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anssi Hannula Subject: Re: DSD over HDMI: audio data packetization Date: Wed, 31 Dec 2014 17:45:28 +0200 Message-ID: <54A41A18.3070005@iki.fi> References: <1420032720.2102.14.camel@gmail.com> <54A3FCD7.2010902@iki.fi> <96A12704CE18D347B625EE2D4A099D195C438E@SHSMSX103.ccr.corp.intel.com> <54A4185E.5010900@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail3.ippnet.fi (mail3.ippnet.fi [62.197.168.3]) by alsa0.perex.cz (Postfix) with ESMTP id 72E1926040D for ; Wed, 31 Dec 2014 16:45:31 +0100 (CET) In-Reply-To: <54A4185E.5010900@gmail.com> 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: Xuebing Wang Cc: "Yang, Libin" , "Lin, Mengdong" , "alsa-devel@alsa-project.org" , "; Wu Fengguang" , "; Takashi Iwai" List-Id: alsa-devel@alsa-project.org 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. > > On 12/31/2014 10:28 PM, Yang, Libin wrote: >> Hi Xuebing, >> >> >>> -----Original Message----- >>> From: Anssi Hannula [mailto:anssi.hannula@iki.fi] >>> Sent: Wednesday, December 31, 2014 9:41 PM >>> To: Xuebing Wang >>> Cc: alsa-devel@alsa-project.org; Yang, Libin; Lin, Mengdong; ; Takashi Iwai; ; >>> Wu Fengguang >>> Subject: Re: [alsa-devel] DSD over HDMI: audio data packetization >>> >>> 31.12.2014, 15:32, Xuebing Wang kirjoitti: >>>> Hi Community, >>> Hi, >>> >>>> I am trying to implement DSD (one bit audio) over HDMI, for Intel >>>> integrated graphics. I am referencing HDMI specification 1.3a. >>>> >>>> Regarding audio data packetization, I am referencing spec: >>>> 5.3.4 Audio Sample Packet >>>> 7.6 Audio Data Packetization >>>> >>>> Q1) Would you please point to me where is the source code to handle >>>> L-PCM audio sample packetization (to implement 5.3.4 Audio Sample >>>> Packet)? >>> It is done by the hardware. >>> >>>> Q2) I admit that I did not carefully read HD-Audio specification. Is >>>> this possible that this L-PCM audio data packetization is done by >>>> *hardware* (e.g HDMI related widgets/pins)? >>> Yes. >>> >>>> Q3) Did we implement "7.2 Audio Sample Clock Capture and Regeneration"? >>> That is done by hardware. With some HDA codecs the video driver calculates >>> the N/CTS values "manually", but AFAIK not on Intel HW. >> As the N/CTS need fs and frequency of TMDS info, the hdmi driver does not >> implement this feature. >> >> We currently are designing an audio link between audio subsystem and other >> components, like video or USB. >> >> Maybe we will add the N/CTS information transmission. So we can calculate >> the N/CTS value in audio or gfx driver. >> >> >>>> Thanks. >>>> Xuebing Wang >>>> >>>> >>> >>> -- >>> Anssi Hannula > -- Anssi Hannula