Will PS3 ever throw out True-HD sounds over optical?

Discussion in 'Playstation Forums' started by Atchi123, Sep 5, 2007.

  1. Atchi123

    Atchi123
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    Hi all
    Just got my PS3 and am hugely impressed but wondered if it may be possible in the near future for firmware upgrades to allow the higher bitrate audio formats over optical? People seem to suggest that optical can support more than 1.5mbps and that it is just the codecs in the machine that limit it? I'd like to know before I have to splash out on a new receiver!
    Tks
    Steve
     
  2. gbailey141

    gbailey141
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    I think you will find that optical will only support upto 1.5mb due to bandwidth restrictions.

    You will only get TrueHD etc via HDMI with the PS3. This means you also will need an amp that can support audio via HDMI.

    Gav
     
  3. gbailey141

    gbailey141
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    PS If you are looking for reasonably priced amp that can do this, then the Onkyo 605 is worth a look. I am very happy with mine.

    Gav
     
  4. Darth_terra

    Darth_terra
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    As mentioned it's not a PS3 restriction is the optical cable spec itself, it's not capable of carrying PCM uncompressed at 5.1, Yes it can carry 1.5mbs PCM but only at 2.0 ie stereo, the only way to get the full 5.1 Uncompressed on the PS3 is via HDMI.
     
  5. Atchi123

    Atchi123
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    OK thanks all. Oh well, looks like I'll be saving the pennies again for upgrading then. There's never a status quo with AV is there??? :suicide:
     
  6. CurlyPutz

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    I have read else where regrading the 1.5Mbs cap on optical leads and I understand this to be true but ....

    Light travels much faster then electrons down copper so how can optical not have the bandwidth? Also, the land-based communications around the world use fibre (speed of light and all that), we are switching 100GB between sites for a customer of mine on fibre, indeed BT are planning to roll fibre out accoss the UK so how can sound over optical not have the bandwidth, it's just digital data?

    Can anyone help me understand this because I am sure there must be a techie reason and it's not just to drive to hardware sales and copy protect systems.

    Cheers, Chris
     
  7. bsimmer3000

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    Yeah im interested to know about this as well as i read a while ago that a standard size short fiber optic cable could carry 14 million gb/s in multi mode and 40gb/s in single mode. i wanna know why we can only carry 1.5mb/s for audio?
     
  8. Tman666

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    Yea i was gutted to find this out as well looks like the yam will be up for a upgrade soon, if i get another black unit might even fool the wife into thinking ive not changed anything :D
     
  9. Stephen Neal

    Stephen Neal
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    The fibre can carry much more than 1.5Mbs. However the electronics at either end that convert the digital signal to an optical one and vice versa still have very real electronic limitations - and these dictate the bandwith of digital signal that can be carried.

    The SPDIF and Toslink coax and optical standards were designed in the days of stereo, uncompressed, 16 bit 44.1kHz CD - with a bit of latitude for 48kHz DAT which was also knocking around. The basic standard is thus around 1.5Mbs - which can carry a stereo 16 bit 48kHz audio signal - and compressed 5.1 Dolby Digital and DTS signals as well.

    A normal Toslink optical connection may well be able to carry a lot more than 1.5Mbs - and some of the electrical to optical converters support higher rates - which is why the PS3 now offers higher bit rates for PCM over such connections (88 and 176kHz sampling for example) - however it is unlikely that any compressed outputs other than DD and DTS at 1.5Mbs or below will ever be offered, as there are no amplifiers around to take >1.5Mbs multichannel audio feeds AIUI.

    HDMI is the current best standard for higher quality multi-channel audio - either in uncompressed PCM 5.1 or 7.1 or a compressed new codec.
     
  10. raymondo1

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    well said stephen neal, i tried to explain this to someone in another thread.
    the fibre isnt the problem, its the electronic interfaces.
    i worked on high end digital mixing consoles that sent many channels of uncompressed pcm down fibre with no bother.....
     
  11. james.miller

    james.miller
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    spdif is capped at around 9.6mb/sec, not 1.5. remember it can happily pass 2 channel pcm @ 192khz/24bit (2 x 192 x 24 = 9,216kbps or 9.2Mbps)
     
  12. AJUK

    AJUK
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    yeah, what he said i was just gonna say that. :rotfl:
     
  13. mr_yogi

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    Isn't 1.5 MB/s = 12Mbits/s?
     
  14. CurlyPutz

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    Cheers Lads! :clap:

    So fibre is good after all, some of what I had read on this pointed to the fibre being the limiting factor, not the optical convertors at each end.

    It still leaves me wondering why not just release updated convertor chips to switch the optical pulses to TTL electronic signals at higher bandwidth / bit rates instead of HDMI for new kit because fibre is generally a better transmission method than copper.

    Cheers again, Chris
     
  15. onkeh

    onkeh
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    Probably more to do with HDCP to be honest, which you don't get over optical.
     
  16. CurlyPutz

    CurlyPutz
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    Thats my feelings too
     
  17. Stephen Neal

    Stephen Neal
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    Yep - absolutely - but that is not a core part of the standard. The PS3 now optionally includes SPDIF output at 88 and 192 kHz sampling - but it is far from compatible with every amp that can accept 1.5Mbs SPDIF - i.e. 32-48kHz 16 bit stereo. A large proportion of consumer amps max out at 1.5Mbs.

    There is no theoretical reason why a SPDIF interface couldn't carry multi-channel PCM - however for many reasons this is not standardised (including DRM) - and thus not possible at the consumer level.

    Of course other fibre systems are available - professional mixing desks have multi-channel PCM fibre interfaces which use bitrates far higher than SPDIF - but these are not consumer systems.
     
  18. Stephen Neal

    Stephen Neal
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    1.5Mb/s (i.e. megabits per second) not 1.5MB/s (i.e. megabytes per second) is the standard rate for uncompressed PCM stereo from a standard CD. That is just under 0.2MB/s (i.e. megabytes per second)
     
  19. mr_yogi

    mr_yogi
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    Thanks for correcting me, I just looked at it quick without thinking it through, added 1+1 and came up with 5 :D

    cheers

    EDIT:

    Out of interest, does anyone know how many amps will accept data at bandwidths way in excess of 1.5Mbps?

    Is it only the latest high end Denons etc. or have most mainstream amps for the last few years been capable of accepting these data rates?
     
  20. raymondo1

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    Of course other fibre systems are available - professional mixing desks have multi-channel PCM fibre interfaces which use bitrates far higher than SPDIF - but these are not consumer systems.[/QUOTE]

    yep we stuffed 28 channels of stereo 192KHz down a single fibre link , of course with totally different electronics than in consumer kit..

    drm certainly a big factor in the choice of interface.
     
  21. Bogside

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    There should be a smilie for bowing. Wow that was impressive:eek::clap:
     
  22. Cool-hand

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    Why not put a IEE1904ish firewire output on the ps3 to help. If you have a pio or similar amp with this input would that help for older systems!

    Rgds

    CH
     
  23. runas

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    ITYM IEEE1394(a or b) for firewire. Not a problem for a decent PC but how many AV amps support firewire?


    The comparison earlier in this thread between comms optical link bandwidths and TOSLink are irrelevant as Stephen Neal says. Most high performance links use glass of only a few microns diameter. This ensures that a single or predetermined number of optical signal(s) pass down the fibre without mixing at the detector and with no or limited reflections causing dispersion. To help this, the optical signal is generated by a laser to provide a coherent focused beam, and the fibre is of a layered construction where the next layer out is a graded material that provides a controlled reflection even when the fibre is curved. The laser and the sensor are designed for large modulation bandwidths. TOSLink on the other hand is a cheap consumer product designed to transfer digitised audio (as was around twenty years ago) between mass produced consumer electronics products. It uses plastic fibre and is driven by simple LED illuminators and cheap sensors. It does the original job well enough, but don't consider it for anything more.

    runas
     
  24. Stephen Neal

    Stephen Neal
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    Sony ditched the iLink / Firewire / IEEE1394a output from the later PS2 models (it was only used by a couple of games for two machine gameplay AIUI) - and I suspect they have no interest in adding support for it in the PS3 just to support a few amps using an interconnect system that has effectively been made obsolete by HDMI?

    AIUI iLink amp interconnects were used in the early days of the new "better than CD" audio formats - which were not allowed to output their higher-quality audio over an unprotected Toslink/SPDIF connection - and instead either had to output analogue or iLink? Now HDMI is available there is no need for the niche iLink version.

    Of course, a PS3 iLink interface might make sense in Japan, where iLink is used to pipe HDTV signals between devices (like set top boxes and hard drive recorders etc.) but I can't see it being added - USB2 does everything Sony need in a high-speed interface...
     
  25. Stephen Neal

    Stephen Neal
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    A small number of high-end amps have had iLink support for advanced audio players (was it SACD or DVD Audio that allowed high quality digital audio to be output via iLink as well as analogue? I can't remember or be bothered to google/wikipedia search!)
     
  26. Cool-hand

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    Both!

    Ta. For replies and of course the hdmi is the final solution...

    Rdgs

    CH
     
  27. Wilt

    Wilt

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    What i'd like to know is if we'll ever get DTS MA over bitsream.
     

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