VOA by Onslaught [web]
screenshot added by algorithm on 2014-08-12 04:05:18
platform :
type :
release date : august 2014
  • 6
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popularity : 51%
  • 0.67
alltime top: #17528
  • algorithm algorithm [code, graphics, sampling, encode]
added on the 2014-08-12 04:05:18 by algorithm algorithm

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Demonstrates the output of my pc encoder that is able to convert full 3 minute audio tracks into a single disk side for playback on a c64.

It is a huge improvement over VQ based methods as it freely allows sliding references into the 4k wavetable instead of being snapped to chunks (8,16 etc) furthermore for quality increase, each chunks amplitude can be updated to 1 of 16 volume levels.

This allows a total of over 65000 16 byte chunks that can be recreated by only a 4k wavetable

This particular example compresses each 16 byte sample into two bytes which consist of a 12bit value for the offset into the wavetable and 4bits of amplitude.

I could have created the full decode via nmi and to reconstruct the next set of 16 bytes (or prepare offset/amplitude) while the previous 16 is being read, but this first implementation worked and left it at that

The oscilliscope effect is rather basic and updates sprite y pointers after each 16 byte chunk has been decoded into the buffers. Per line update could have been possible, but most of the code had been finished already and did not recode the demo.

The demonstration utilises the filter based d418 method, hence quality may vary on machine to machine, however autodetect is used in the demo in order to try and ensure that quality does not suffer between the two sid models.

The example tune has many repeating sections, however this encode method works well for any type of audio including audio with no repeating sections.

Quality can be increased further via multiple offsets and mixing (infact i have already created encoders that can mix 4 chunks with amplitude) To be implemented in a future demo

Disk is 40 tracks. Also remember that if you are running this demo on an emulator, make sure it has accurate sid emulation (preferably latest version of winvice or micro64) It does not sound too great on hoxs64
added on the 2014-08-12 04:06:56 by algorithm algorithm
Cool stuff...

now let's see if we can get it on POKEY, too ;)
rulez added on the 2014-08-12 08:44:21 by Heaven/TQA Heaven/TQA
Very impressive!
rulez added on the 2014-08-12 11:02:19 by Nitro/Black Sun Nitro/Black Sun
Sounds good on 6581 but crappy on a new one.
added on the 2014-08-12 15:55:44 by cryer cryer
awesome tech stuff, as always!
rulez added on the 2014-08-12 22:01:39 by bonefish bonefish
video is not available in Finland, wth..
added on the 2014-08-19 10:35:26 by leGend leGend
Algorithm awesome as usual :D
rulez added on the 2014-08-19 12:33:30 by rez rez
The video is blocked in some countries due to youtube detecting the audio as copyrighted material.

Solution? Either use a proxy or download the demo and run on emulator/real c64. Make sure the emulator is up to date and using accurate SID emulation otherwise audio will be reduced to mush.
added on the 2014-08-19 14:06:55 by algorithm algorithm
@Algorithm. I think there is a small bug in the demo. I guess you try to detect the sid-modell but if you have a new one with a 330 Ohm resistor (old trick to hear samples) then it's totally crappy. You can even hear this within the vice-emulator. That was also the reason why I wrote it sound crappy, on a old one or a *stock* new one, the music is goog.
added on the 2014-08-27 15:59:33 by cryer cryer
Its impossible to detect whether a sid chip has the resistor soldered on it. By default the SID detection will detect between old and new sid and adjust accordingly. Although I could have included an option to select "new sid with resistor" and then select 6581 mode
added on the 2014-09-03 01:02:11 by algorithm algorithm
rulez added on the 2014-09-03 17:24:38 by fra fra
Rutube video, available so far, without any copyright issue :)
added on the 2014-09-03 17:25:56 by fra fra
tech porn

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