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MQA: Revolutionary British streaming technology

Discussion in 'Sound Science' started by bigshot, Dec 8, 2014.
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  1. bigshot
    This article says that the compression scheme focuses on timing, not frequency response. How is that even possible? You can take a lossy file and sum it back with a lossless file and the timing is precisely the same. How does MP3 possibly alter timing? Is this some kind of scheme for addressing jitter introduced by streaming? If so, it isn't necessary. I stream through my house using AAC and Airports and the jitter is well below the threshold of audibility.
    Bacon Bits likes this.
  2. RRod
    I know a really svelte way of delivering 24/96 content in an audibly lossless way at about 256kbps, but I can't tell you b/c Meridian might nab it from me [​IMG] 
    BTW, why lock this thread previously, mod? I'm sorry but when a graph like this is part of the pitch, the product is fair game for skepticism. 
  3. cer
    That is a genuinely lovely graph. Reel-to-reel and LP both much better quality than DVD-A/SACD. Streaming worse than cassette. Definitely not stupid or wrong or anything.
  4. Hudson
    The convenience plot is also odd, I wonder how they compile that.
    I had a quick read of the article and filled it under meh, too much ambiguous gumph.
    The article and the MQA website are pretty confusing, is this a just a new codec or streaming service or both?
  5. pwiles1968
    There is  a lot more info here with several articles - http://www.realhd-audio.com/
    As far as I can tell is is not a new codec, it can be imbedded in existing codecs such as FLAC, it involves adding additional information embedded in the file, if you have an MAQ decoder you get the extra info, if not it plays as normal.
    I have been reading a bit, appears to be that the reason there are acoustic benefits with 24/96k or higher files is not necessarily the additional bandwidth it is the ability to get better timing, we can not hear the frequency but we can hear the timing errors even if they are very small, MQA is able to improve the timing with smaller files, approx CD bandwidth that is equivalent to 24/192 or better ?
    This what I have been able to gather so far.
  6. cjl
    CD already has fantastic timing precision though (much, much better than just the sample time).
  7. bigshot
    It talks about throwing out ultra high frequencies that are down at -70dB. It sounds like they are just going to extend some of the compression scemes of MP4/redbook to high bitrate/high sampling rate files.
    It seems to me that no one who uses FLAC or high sampling rate files cares a bit about file sizes. They actually want the file size to be as large as possible to maintain the purity of every bit possible. The second they hear about throwing away inaudible frequencies, their OCD will kick in and they will demand that all the inaudible sound be put back in.
    I'm betting that this will just be a less compact lossy format designed to preserve a little bit more of the inaudible... and ultimately audibly transparent, just like every other format above AAC192.
    The timing thing may just be some sort of buffering during streaming to reduce jitter... which is inaudible anyway.
    They also talk about "tailoring the compression to different parts of the distribution chain". That sounds to me like one file format that is converted to different levels of compression on the fly, depending on whether you are playing it on a home stereo system or streaming it to your phone.
  8. Roly1650
    This article is a bit more informative : http://www.realhd-audio.com/?p=3857

    Apparently the packaging is a little like HDCD if you can remember that format, the media contains a "flag" which signals the decoder for the higher resolution content, otherwise it plays back at standard resolution.

    The timing issue is only obliquely related to jitter, it's based on new research claiming that human hearing is more sensitive in the time domain than it is in the frequency domain. Conveniently for Meridian 24/96 doesn't cut it, the sample rate is too slow for the time intervals we can apparently resolve, it has to be 24/192, but you knew that was coming, right?

    The other thing discussed is that higher resolution doesn't necessarily increase the audible content, it makes the filtering easier, but no mention is made of how they get rid of the negative effects of this in the standard resolution files, once the additional content has been triggered and the whole issue seems like it's a well worn path anyway.

    Its interesting that the Meridian graph has gone through at least two third party revisions including one by John Slau of Benchmark.
  9. stv014
    It is actually not new research that inter-channel delay of as low as 10 us can be detected under best case conditions. Nor is the sampling theorem, according to which sampling does not limit the time resolution, only the bandwidth.
  10. Roly1650
    But, I was only paraphrasing the article and Meridians claims, honestly I was officer.........:D
  11. stv014
  12. nick_charles Contributor
    show me some level matched double blind tests and I'll still ignore it ...
  13. ralphp@optonline
    The 5000 pound elephant in the room is that hardly anyone dares to compare, via a controlled double test, the sound of standard redbook audio and the sound of high resolution audio, particularly when the redbook audio is made by downsampling the high resolution audio. In the article cited by the OP the listeners were played high resolution files but not redbook files, which I content would have sounded equally good. In other words, more useless snake oil.
  14. Greenears
    I resemble that remark!  I'm running a whole series of ABX tests on 16 vs 24, where 16 is derived from 24 with SoX.  It's easy, and fun.  A few people have joined in. It's on the other thread 24 vs 16.  Pitch in we could use some help.  3 or 4 people have actually run something.  The rest are sniping at us. 4999 pound pachyderm? 
  15. bigshot
    It doesn't matter whether it's redbook. I'd love to see someone discern AAC 256 VBR in a test with "HD" audio!
    HAWX likes this.
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