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2nd June 2009, 22:42 | #1 | Link |
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FLAC vs HD audio questions
I tried searching google and here, but can't seem to shake the needle out of the search result haystack.
Can someone explain or point me to where FLAC is compared and contrasted with DD-TrueHD & DTS-HDMA. I understand they are all lossless, but I assume FLAC is inferior in some way? Thanks in advance, and I apologize if this is a stupid/common question. Thanks |
2nd June 2009, 22:53 | #2 | Link | |
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2nd June 2009, 22:58 | #3 | Link |
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FLAC has better compression versus TrueHD and probably DTS-HD as well
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2nd June 2009, 23:21 | #5 | Link |
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Thanks for the responses guys.
I figured the output would be the same since they are all supposed to be "lossless." What about bitrates? all 7.1 channel support? What about cable (FLAC limited in some way over spdif like HD audio). If FLAC has better compression than the non-free options why are the paid ones used at all? Last edited by Karkas; 2nd June 2009 at 23:31. Reason: EDIT: Realised my example was incorrect, SPDIF can only carry core audio from HD audio |
2nd June 2009, 23:56 | #6 | Link | |
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3rd June 2009, 00:36 | #8 | Link | |
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This really depends on the source bitdepth and number of channels. An extreme example is 16 bit, 2 channel DTS-HD MA, which would compress a lot with FLAC, down to perhaps less than half of the original size. With 24 bit 5.1 or 7.1 I've found there isn't always much of a saving - maybe 10% or so. I haven't yet found a lossless audio track though that's bigger as FLAC than whatever it was originally. FLAC supports eight channels and any sample rate. Actually there is a maximum sample rate but I forget what it is - it's really high. FLAC is limited in the sense that you can't transmit it over S/PDIF. So it has to be decoded at source and then only stereo PCM can get sent over S/PDIF. It also can't be sent over HDMI but of course it can be decoded and all channels sent as PCM. |
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3rd June 2009, 00:38 | #9 | Link | |
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Correct me if I am wrong, but I thought TrueHD & HDMA are not mandatory part of the specs for BR & formerly HD-DVD. |
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3rd June 2009, 02:30 | #11 | Link | |
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Maybe FLAC will get used in the future though? I suspect it's lack of backwards compatibility ruled it out this time, if it was ever considered. I don't know how long it had been around when the new HD formats were being decided on. Maybe it wasn't mature enough. There's no hardware support for FLAC in the home cinema area. At least none that I know of. So even if you could coax your player to pass FLAC out over HDMI, or S/PDIF for that matter, there aren't any decoders available to plug in at the other end. |
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3rd June 2009, 02:32 | #12 | Link | ||
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3rd June 2009, 02:54 | #15 | Link | |
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That said, it sucks that they decided to use proprietary audio codecs. I'm glad there are people out there who enjoy reverse-engineering. Last edited by jruggle; 3rd June 2009 at 02:58. Reason: channel mixing -> channel weighting |
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3rd June 2009, 03:15 | #16 | Link | |
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Thanks! |
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4th June 2009, 15:49 | #19 | Link |
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...and was it 16 or 24 bit?
Here's an example I've just done. Source is 24 bit 5.1 DTS-HD MA, 1:36:56 long. Source 2.73GB FLAC 2.35GB So a 14% saving converting to FLAC. Converting a 24 bit source to 16 bit FLAC offers really big space savings, although it's not lossless obviously. Good enough for me though - I can't tell the difference. In this case the above audio can be reduced to a 0.88GB 16 bit FLAC track, making it a third of its original size. In fact it's smaller than the DTS core (1.02GB). |
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