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HDMI discussion - Page 10 — Parallax Forums

HDMI discussion

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  • roglohrogloh Posts: 5,833

    @Rayman said:
    Is it just stereo with hdmi? Or do we know how to do better? Wonder how that would work..

    For now it's just two channel (stereo) audio. In theory we can generate a different audio format with up to 8 channel sources, however there are limitations in terms of sample rates and number of channels at lower resolutions that the P2 is capable of sending over DVI/HDMI. At 31.5kHz VGA line rate, we can send around 4 dual channel samples per line which is enough for 126kHz stereo audio or half that for 4 channels, or 1/3 that for 6 channels. Currently we don't really have enough P2 clock cycles per scan line to encode more than one audio packet per scan line so higher audio channel rates aren't easy to achieve at least in text modes or when any pixel doubling is occurring. Perhaps it could be done in some fixed PSRAM mode where you have more free time while you wait for the PSRAM data to arrive.

  • HDMI can do multi-channel, but that requires multiple packets per scanline (unless doing that 32k hsync trick mentioned earlier). Other problem is that which channel goes where is a bit under-specified for anything that isn't the standard 5.1 setup.

  • pik33pik33 Posts: 2,382

    I bought a RPi monitor - it has HDMI input with audio. I need some time to experiment with this and audio enabled HDMI...

    The monitor managed to display what I generate from a P2 (1024x600@50 Hz)

  • cgraceycgracey Posts: 14,204

    @pik33 said:
    I bought a RPi monitor - it has HDMI input with audio. I need some time to experiment with this and audio enabled HDMI...

    The monitor managed to display what I generate from a P2 (1024x600@50 Hz)

    That looks great! Do you have some code I could try here? I am wondering if my TV's can show this, too.

  • pik33pik33 Posts: 2,382

    https://github.com/pik33/P2-Retromachine-Basic
    This is a Basic interpreter for EC32 that use the same video driver I used in the player on the picture
    The player is here : https://gitlab.com/pik33/P2-retromachine/-/tree/main/Propeller/P2P16?ref_type=heads
    Both programs need EC32, HDMI at 0, AV at 8 and USB at 16

    @cgracey said:

    @pik33 said:
    I bought a RPi monitor - it has HDMI input with audio. I need some time to experiment with this and audio enabled HDMI...

    The monitor managed to display what I generate from a P2 (1024x600@50 Hz)

    That looks great! Do you have some code I could try here? I am wondering if my TV's can show this, too.

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