4 ms·

The HDMI port on the back of your computer is purely an 'output' port. There is no circuitry there to read an input signal. Adding this to existing chips would

by nevdka 12y ago

The HDMI port on the back of your computer is purely an 'output' port. There is no circuitry there to read an input signal. Adding this to existing chips would make them more expensive, and most customers would never use this functionality, so the chip companies don't bother adding it. So yeah... it's a hardware issue, not a driver issue.

UnoriginalGuy 12y ago
Where did you get this information? Looking at the HDMI spec what you're saying makes no sense, everything is just a data channel, there is nothing specific for input and output. In fact if what you said was true they would need crossover within the cable which they don't have, so what you're saying is they null terminate 1/2 of HDMI's data channels? Yeah, you need to explain this, it seems utterly at odds with all the information I can find. And I cannot wrap my head around the design of the system you're describing (i.e. the logistics of an "input only" or "output only" digital system).
- wmf 12y ago
  Pins 1-12 (which carry the audio/video data) are unidirectional; some of the other pins are bidirectional but very low bandwidth.
  - UnoriginalGuy 12y ago
    That doesn't remotely address anything I nor the person above said. Nobody is debating if HDMI as sinks and sources, it does, what is being asked is how you'd design the source so that it could not act like a sink on the electronic lines on an all-digital system. I just read over the spec again looking for what you might be referencing but I cannot locate it. Here's a link: http://www.microprocessor.org/HDMISpecification13a.pdf http://www.microprocessor.org/HDMISpecification13a.pdf Can you be more specific.
    - pdx 12y ago
      There are lots of call outs of source vs sink, but page 38 will perhaps convince you. It shows the sink is the input to a differential op-amp, while the source is a current source. The same lines are connected to different circuits, depending on if you're a source or a sink. EDIT: This looks like an interesting little box, if somebody does need the ability to read HDMI. You would still need to save it and then re-stream it, I think, to get it to your monitor. https://www.blackmagicdesign.com/products/h264prorecorder https://www.blackmagicdesign.com/products/h264prorecorder
      - UnoriginalGuy 12y ago
        The diagram on 39 kind of contradicts that. In fact it indicates they have exactly the same circuitry.
        pdx 12y ago
        No, it doesn't.
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by nevdka 12y ago

UnoriginalGuy 12y ago

Where did you get this information? Looking at the HDMI spec what you're saying makes no sense, everything is just a data channel, there is nothing specific for input and output. In fact if what you said was true they would need crossover within the cable which they don't have, so what you're saying is they null terminate 1/2 of HDMI's data channels? Yeah, you need to explain this, it seems utterly at odds with all the information I can find. And I cannot wrap my head around the design of the system you're describing (i.e. the logistics of an "input only" or "output only" digital system).

wmf 12y ago
Pins 1-12 (which carry the audio/video data) are unidirectional; some of the other pins are bidirectional but very low bandwidth.
- UnoriginalGuy 12y ago
  That doesn't remotely address anything I nor the person above said. Nobody is debating if HDMI as sinks and sources, it does, what is being asked is how you'd design the source so that it could not act like a sink on the electronic lines on an all-digital system. I just read over the spec again looking for what you might be referencing but I cannot locate it. Here's a link: http://www.microprocessor.org/HDMISpecification13a.pdf http://www.microprocessor.org/HDMISpecification13a.pdf Can you be more specific.
  - pdx 12y ago
    There are lots of call outs of source vs sink, but page 38 will perhaps convince you. It shows the sink is the input to a differential op-amp, while the source is a current source. The same lines are connected to different circuits, depending on if you're a source or a sink. EDIT: This looks like an interesting little box, if somebody does need the ability to read HDMI. You would still need to save it and then re-stream it, I think, to get it to your monitor. https://www.blackmagicdesign.com/products/h264prorecorder https://www.blackmagicdesign.com/products/h264prorecorder
    - UnoriginalGuy 12y ago
      The diagram on 39 kind of contradicts that. In fact it indicates they have exactly the same circuitry.
      - pdx 12y ago
        No, it doesn't.

deleted 12y ago

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