13 August 2016, 22:08 | #1 |
Glastonbridge Software
Join Date: Jan 2012
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A 5th Audio Channel on the Amiga
ok so someone plugged his Amiga's composite out signal into an amp and played samples over it by drawing on the screen
http://jmp.no/blog/a-5th-audio-channel-on-the-amiga |
13 August 2016, 22:47 | #2 |
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Yeah nice, this is possible with any machine that outputs composite.
Here's a C64 demo that did this a long while ago using VIC noise: [ Show youtube player ] |
14 August 2016, 11:04 | #3 |
Phone Homer
Join Date: Jun 2006
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Can you have anything on screen but static?
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14 August 2016, 23:20 | #4 |
Glastonbridge Software
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if you were clever perhaps you could put something else on the screen, maybe using colour, i don't know... the C64 video posted above also has a scroller across the middle. The problem is it's the pattern on the screen that produces the sound. Then again if you were using something like Indivision or the HDMI output of the Vampire accelerator you could still output this stuff to composite while displaying something else independently on the other output (?)
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15 August 2016, 00:19 | #5 |
Phone Homer
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Maybe you can have something on both RTG and normal display?
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15 August 2016, 17:34 | #6 |
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I thought you couldn't have RTG and standard display at once.
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15 August 2016, 18:46 | #7 |
Computer Nerd
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Interesting hack. Too bad it's not useful.
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16 August 2016, 09:58 | #8 |
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The OS doesn't support using both at once, but there's no technical reason I can think of that you can't bang the hardware directly to get output on the native screen.
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16 August 2016, 18:53 | #9 | |
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Quote:
I have better hack for you - use 4 bit TTL output from video port in same way as DCTV or HAM-E or similar. Code PCM on video then collect data - you can realtively easy output 16 bit stereo PCM 48kHz even on naked A500 in such way - this can be done with simple state machine on few TTL circuits, on hires line (640 pixels) 320 bytes can be coded so single line can cary 16000 bytes per second to feed 48000 16 bit stereo you need 12 hires lines - this area can be masked in TTL logic to avoid visible garbage... |
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17 August 2016, 23:15 | #10 |
Glastonbridge Software
Join Date: Jan 2012
Location: Edinburgh/Scotland
Posts: 2,243
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i did wonder today about using sprites instead of copper palette changes to achieve the effect. so one could render samples into sprites and play with 8 channels by putting the sprites in different places! (Maybe repeating them across the screen to increase the loudness)
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