• how to extact audio from "display port"

    From hput@21:1/5 to All on Tue Jun 28 16:17:25 2022
    I'm soon to have a computer with a video card that outputs only thru
    a "display port".

    Of course I can run an extended rca mini jack from the computers sound
    plug in back.

    But in the long run:

    There must be some way to separate the audio and video on a
    "display port" output? I know they have adapters from "Display port"
    to hdmi.

    But having no luck googling up a tool that splits the audio signal out
    of display port..

    Can anyone suggest something that might help?

    Also, am I wrong in thinking that the sound quality at the sound card
    (a Quadro M4000 8GB) "Display port" will be superior to the sound at
    the rca mini port in back?

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  • From Paul@21:1/5 to hput on Tue Jun 28 17:45:13 2022
    On 6/28/2022 4:17 PM, hput wrote:
    I'm soon to have a computer with a video card that outputs only thru
    a "display port".

    Of course I can run an extended rca mini jack from the computers sound
    plug in back.

    But in the long run:

    There must be some way to separate the audio and video on a
    "display port" output? I know they have adapters from "Display port"
    to hdmi.

    But having no luck googling up a tool that splits the audio signal out
    of display port..

    Can anyone suggest something that might help?

    Also, am I wrong in thinking that the sound quality at the sound card
    (a Quadro M4000 8GB) "Display port" will be superior to the sound at
    the rca mini port in back?


    They make the following kinds of adapters. I only have the first one.
    I would hope the computer only routes sound to video connectors that
    are in usage. If your video card had three connectors, it's not necessarily
    the case that all three have the same audio signal at the same time. But
    I haven't tested this. That would require me to buy more of these.

    HDMI --- (box) ------- VGA
    ------- Stereo Audio
    ------- (some do SPDIF, but that's a different product)

    DP --- (box) ------- VGA
    ------- Stereo Audio

    These can also be equipped with a miniUSB
    solely for +5V power. Even though the video card
    DP and video card HDMI have 5V power pins on the
    connectors. My video card provides enough power, that
    any of the adapters I've tried, they worked.

    Some equipment in your AV rack, could have poor +5V on one
    of those display connectors, and that's why the adapter has
    an additional (optional) +5V input.

    Things like soundbars can do audio-drop to run their speakers,
    then pass an HDMI-out to a TV set. This allows the soundbar to
    have audio and the TV to have video.

    Generally, I don't recommend buying roomfuls of toys of
    this nature. Test the kit you bought first, and see if it is
    satisfactory. Maybe you have enough goods right now to get
    the job done. Maybe the motherboard audio is "good enough".

    Adapters could range from $30 to several hundred (for Apple docks)
    that do conversions. Some of the adapters could be more expensive
    than the video card they're connected to.

    Sound cards vary a bit on background noise level. A Creative
    with a shield box around it, might be -108db. Computer sound (HDAudio)
    could be -70db. The worst part of computer sound, is when you move the
    mouse and "digital noises" can be heard in your speakers. Concert hall
    music can have sufficient dynamic range, to need a clean noise floor.
    Many other kinds of music don't really need to be all that clean.
    But things like mouse-noises, those suck. Sometimes you get stuff
    like that from a grounding problem in the computer room.

    These are moments when you start retrofitting stuff.

    I haven't seen any HDMI to four 1/8" connectors for 7.1 sound. HDMI
    and DP should at a minimum support 8 channel LPCM (linear pulse code modulation), which is the "patent-free" audio format on video. There
    are various Dolby options no one cares about. A sound bar might pick
    off 5.1 and drive its own Sub (as your DVDs might have a 5.1 audio track).

    Your new motherboard might also have TOSLink, which is SPDIF sent
    via red LED light. Which is fine if you have an AV receiver with
    a TOSLink input. Otherwise (like for me), the TOSLink is a waste
    of time. My amp is one I built myself and there's no TOSLink on it :-)

    You could send audio over Bluetooth... but... don't do that.
    It's pretty awful. It's like listening to the lowest bit rate MP3.

    There is a software product, RightMark Audio, that can be used to
    test computer sound. I'm not recommending a copy, just look
    for a reviewer that uses it and see what it can show. SO if you
    were interested in some Creative soundcard, you could combine the
    search term "RightMark" and get some graphs.

    Paul

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  • From Computer Nerd Kev@21:1/5 to hput on Wed Jun 29 07:51:40 2022
    hput <hputn3@zohomail.com> wrote:
    There must be some way to separate the audio and video on a
    "display port" output? I know they have adapters from "Display port"
    to hdmi.

    But having no luck googling up a tool that splits the audio signal out
    of display port..

    HDMI and DisplayPort are both entirely digital standards, so in
    neither case is there a conventional audio signal at the port. It's
    just digital signals basically like those feeding into the sound card/onboard-chip in the computer, so you effectively need another
    sound card like device to plug in to the DisplayPort and supply
    an analogue audio output.

    Can anyone suggest something that might help?

    I haven't seen such a device myself, but they probably exist. Maybe
    adapters to VGA etc. with audio output built-in will be cheaper,
    though they'll likely be poor quality.

    Also, am I wrong in thinking that the sound quality at the sound card
    (a Quadro M4000 8GB) "Display port" will be superior to the sound at
    the rca mini port in back?

    Seeing as the former is digital, they're not comparable. In
    practice it would depend on the quality of the sound
    card/onboard-chip in your computer compared to whatever device you
    plug into the DisplayPort which does the same job.

    --
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  • From Computer Nerd Kev@21:1/5 to Paul on Wed Jun 29 11:12:48 2022
    Paul <nospam@needed.invalid> wrote:
    On 6/28/2022 5:51 PM, Computer Nerd Kev wrote:
    hput <hputn3@zohomail.com> wrote:
    Also, am I wrong in thinking that the sound quality at the sound card
    (a Quadro M4000 8GB) "Display port" will be superior to the sound at
    the rca mini port in back?

    Seeing as the former is digital, they're not comparable. In
    practice it would depend on the quality of the sound
    card/onboard-chip in your computer compared to whatever device you
    plug into the DisplayPort which does the same job.

    The DisplayPort 8ch LPCM and the HDMI 8ch LPCM, are digital
    from end to end and no degradation is present. You stuff the
    digital samples into the interleaved stream in the DP output.

    The sound is only as good as the source.

    It is when the 8ch LPCM is converted to analog with a DAC,
    that the degradation occurs.

    Yes, including any noise that the analogue signal picks up while
    going down a long cable after leaving the DAC. But my point was
    that without knowing the quality of the DAC feeding that "rca mini
    port in back", it's unclear whether using a different DAC connected
    to the DP would offer any advantage, and either way the sound
    quality will have nothing to do with that Quadro M4000 GPU. The
    real issue seems to be an assumption by the OP that the GPU has an
    audio DAC built-in, which isn't the case.

    --
    __ __
    #_ < |\| |< _#

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  • From Paul@21:1/5 to Computer Nerd Kev on Tue Jun 28 20:34:34 2022
    On 6/28/2022 5:51 PM, Computer Nerd Kev wrote:
    hput <hputn3@zohomail.com> wrote:
    There must be some way to separate the audio and video on a
    "display port" output? I know they have adapters from "Display port"
    to hdmi.

    But having no luck googling up a tool that splits the audio signal out
    of display port..

    HDMI and DisplayPort are both entirely digital standards, so in
    neither case is there a conventional audio signal at the port. It's
    just digital signals basically like those feeding into the sound card/onboard-chip in the computer, so you effectively need another
    sound card like device to plug in to the DisplayPort and supply
    an analogue audio output.

    Can anyone suggest something that might help?

    I haven't seen such a device myself, but they probably exist. Maybe
    adapters to VGA etc. with audio output built-in will be cheaper,
    though they'll likely be poor quality.

    Also, am I wrong in thinking that the sound quality at the sound card
    (a Quadro M4000 8GB) "Display port" will be superior to the sound at
    the rca mini port in back?

    Seeing as the former is digital, they're not comparable. In
    practice it would depend on the quality of the sound
    card/onboard-chip in your computer compared to whatever device you
    plug into the DisplayPort which does the same job.


    The DisplayPort 8ch LPCM and the HDMI 8ch LPCM, are digital
    from end to end and no degradation is present. You stuff the
    digital samples into the interleaved stream in the DP output.

    The sound is only as good as the source.

    It is when the 8ch LPCM is converted to analog with a DAC,
    that the degradation occurs.

    This assumes nothing is going on, such as a previous scam
    where a 24 bit digital audio standard, some of the manufacturers
    were setting the 8 least significant bits to 0 permanently,
    causing the audio actually sent to be 16 bit audio. So stupid
    stuff has happened in the past, but I haven't heard of this
    happening with the present day stuff.

    There was at least one adapter or dock, that had SPDIF
    as an output. Which would give you stereo with 24 bit accuracy.
    The SPDIF is converted back to analog, inside the AV Receiver/Amp.

    "HDMI to VGA + Optical Toslink SPDIF + 3.5mm Stereo Audio Converter Support 1080P"
    https://www.amazon.ca/Security-01-Optical-Toslink-Converter-Support/dp/B01FVFWMAY

    You can also convert VGA back into HDMI, but this is a bad idea.
    Only mentioned for completeness. There should be HDMI to HDMI+Audio,
    as that's the sort of thing soundbars use.

    Paul

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