algorithm information 167 glöps
- general:
- level: user
- personal:
- first name: Naveed
- last name: Khugiani
- demo Amiga OCS/ECS Impassioned by Onslaught [web]
- Onslaughts contribution to the Flashback 2015 demo compo
An Amiga OCS demo that can run on anything from an unexpanded 68000 based 512k amiga system (a500) to higher spec AGA machines with 68020+
There were some issues when the demo was played back in the compo.
Amiga hardware in combination with projector caused screen shearing in bright areas of the screen destroying most of the screen and turning it into black and white.
On most CRT's the rightmost edges of the screen should not be displayed. I took into account
Unfortunately the visible area reported by winuae while the projector displayed the whole width showing the artifacts.
The shadow dancer part seemed buggy in the compo machine, large rectangular 32 pixel or so block corrupted all the way on the left side of the screen. - isokadded on the 2015-06-07 20:45:38
- demo Amiga OCS/ECS 28kbs
- Trixter. Yes it would be better. However there was not enough disk space left :-). However I did underestimate the decode speed and could have used more efficient final packing of each 256 frame chunk to fit the 64k code book. In the current implementation, it manages to load and semi depack a 256 frame chunk in around 3 seconds. (Where it has around 20 seconds or so till the next section :-) also ram usage is 4k instead of 64k. But that could have been resolved by only using dual stream buffer instead of quad.
- isokadded on the 2015-04-22 09:10:31
- demo Amiga OCS/ECS 28kbs
- The audio in essence is a dictionary variant with adjustable amplitudes within the dictionary.
The main work is recreating the 4k sample table which is generated via iterations and genetic refinement.
From a 4k dictionary, its possible to gain 4088 8 byte unique sample data. combined with one of 16 ampitudes, this gives 15x4088+zero amplitude=61321 8 byte pieces that are used to recreate the audio.
For each 8 byte chunk, 12bits store the offset into the 4k dictionary and the other 4 bits store the amplitude. This way a fixed pack rate of 4:1 (in this example)
Ofcourse chunk sizes can be increased for higher pack rate along with increasing the 4k table to a larger amount.
Using the above variant. It beats ADPCM3 in quality in combination to overall being the equivalent of 2bits of data per byte.
There are many other variations possible as well including multiple mixing of offsets into a chunk as well as repeat/fill methods which increase the pack rate and keep similar quality.
Decode is very straightforward. convert the 12bit value to the offset into the table, then read each byte and lookup the desired byte from the amplitude table. - isokadded on the 2015-04-13 00:58:50
- demo Amiga OCS/ECS 28kbs
- The audio encoder works well for any type of audio regardless of complexity, the track was chosen as I had previously test encoded the video (which took some time) and did not want it to gather dust :-)
- isokadded on the 2015-04-11 16:21:40
- demo Amiga OCS/ECS 28kbs
- youtube link here.. Warning, video quality suffers even more.. https://www.youtube.com/watch?v=02a07-nTm4k&feature=youtu.be
- isokadded on the 2015-04-11 15:27:14
- demo Amiga OCS/ECS 28kbs
- Algorithm presents - 28kbs - A full 4 minutes of unrestricted non-looping audio and video streaming from a 880k floppy and running on an unexpanded amiga 500 system (no extra ram expansion).
It has been tested on other configurations as well (using Winuae) from 68000 to 68040 AGA - Let me know if there are any bugs on other configs on the real thing.
The data rate in the demo is the equivalant of a 28kbs stream (3.5k a second). The audio is at 2.5k per second stereo while the video is running at over 12 frames per second using 1k per second.
The main magic comes from my pc based video and audio encoders that utilise some state of the art genetic algorithms and meta-heuristics to generate the data.
The video leaves a lot to be desired, treat this more as a swirling motion effect with emphasis towards audio quality instead.
The demo for flashback was complete two months before schedule and due for release in June 2015. I was rather bored the last couple of days, hence decided to put this quick audio/video stream demonstration together. - isokadded on the 2015-04-11 04:07:48
- demo Amiga OCS/ECS Amigaluscious by Onslaught [web]
- Having a video sequence of a woman gaping open her arsehole is not exactly youtube material :-) ahh. and OCS OCS OCS :-)
- isokadded on the 2015-03-06 22:50:49
- demo Amiga OCS/ECS Amigaluscious by Onslaught [web]
- Next demo finished now and 3 months before schedule :-) just some fixing to run on all Amiga systems and some gfx replacement
- isokadded on the 2015-03-06 20:57:49
- demo JavaScript My god, it's full of sinus!
- Great work there.
- rulezadded on the 2015-01-24 15:59:52
- demo Amiga OCS/ECS Amigaluscious by Onslaught [web]
- The whole video sequence would be nearly fine with youtube apart from the few seconds in the middle of the video sequence that would be classed as extreme adult visual content in comparison with boobs. Youtube would no doubt have issues with this section :-)
This is just really a test showcase of the encoder (and by all means, the video and audio decode is severely unoptimised) Huge room for improvement here (in particular also changing the entire video decode method) Tile based 8x8 decode is not one of the amiga's strong points in comparison to the C64 (that can output a whole 8x8 4 color block with a single byte plot).
Furthermore I am using a really crude version of "deblocking" via shifting x and y offset by 4 pixels per alternate field. If not looking too great on real amiga and CRT, it will look even worse on an emulator or video upload if not at 50hz
For those that want to see the demo without having to run the amiga emulator, below is the dailymotion link.
http://www.dailymotion.com/video/x2ebl4a_amigaluscious-a-demo-for-the-amiga-500-ocs-512k_tech - isokadded on the 2015-01-09 14:17:47
account created on the 2011-01-25 21:59:22