On 10/14/14, 10:30 PM, Andrej Falout wrote:
Hello Pierre-Louis,
On Wed, Oct 15, 2014 at 3:43 AM, Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com mailto:pierre-louis.bossart@linux.intel.com> wrote:
On 10/13/14, 7:49 PM, Andrej Falout wrote: 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.Me too :) Absolutely every HDMI related chip I examined specs for and tested, including the cheapest of the cheap ones made as HDMI repeaters for splitters and audio extractors, supported DSD stream passing (Both up and down stream), just as they did all other audio bitstreams.
For example: http://www.mds.com/system/resources/BAhbBlsHOgZmSSIuMjAxMy8xMC8xNi8xNy8yOS80...
Can you please point out a specification or other document that say otherwise?
You are not looking at the right specifications. You need to look at HDMI interfaces for PCs, and I maintain that most of them don't support DSD.
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 marketsIt seems that you are talking about coding/decoding, not bitstream multiplexing? Same TMDS stream multiplexing is used for all audio streams in HDMI - weather native (PCM/DSD) or encoded (AC3, DTS, ...) The only real difference that I can see is the stream setup as described in my OP ("Table 47 CEA Short Audio Descriptor for Audio Format Codes 9 to 13", (eg setting the format code, bittness, etc))
and there was no real format to convey DSD over PCM frames until the DOP format was created in 2012.Again, I am talking about native DSD formats/streams, not DoP - which is in essence PCM. HDMI specs do not know or need DoP. HDMI is capable of native DSD transfer since version 1.2. See point #5 in my OP.
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.As you say, these are rather straightforward to implement, as evident from the HDMI specification which describes the stream setup. Same specification also described DSD stream setup, which is is essence exactly the same, just uses the different identifiers. (CEA Standard PDF, page 66, table 47. HDMI specs version 1.3a, pages 72-73 for DSD(One Bit Audio) and DST audio packet header and body formats)
Can you point out a documented case where "these modes have been dropped"?
HDMI only requires 48kHz 2ch really.Even the HDMI version 1 requires "8 channel LPCM http://en.wikipedia.org/wiki/Linear_pulse_code_modulation, 192 kHz http://en.wikipedia.org/wiki/Hertz, 24-bit audio capability" : http://en.wikipedia.org/wiki/HDMI#Version_comparison
Wrong. See the HDMI spec, not Wikipedia. The only requirement is: If an HDMI Source supports any HDMI audio transmission, then it shall support 2 channel L-PCM (using an IEC 60958 Subpacket structure), with either 32kHz, 44.1kHz or 48kHz sampling rate and a sample size of 16 bits or more.
Additional rates are not required and often not implemented: An HDMI Source is permitted to transmit L-PCM audio data at sample rates of 32kHz, 44.1kHz,48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz.
DSD is equally optional: A Source may transmit One Bit Audio at an fS (1/64th of the bit rate) of 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz. Any Source capable of supporting One Bit Audio should support an fS of 44.1kHz, corresponding to a bit rate of 2.8224MHz.
May and should are not mandatory statements.
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.There is about 30 million DSD capable DACs in the world today, conservatively speaking, most of them multi-channel capable (See point #3 in my OP). I appreciate that there are a few USB DSD DACs out there too, and even 2 (two) multi-channel models. ;)
I wish you luck. over and out.
Thanks, Andrej Falout