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 Post subject: Re: Atari 8 bit moviez less then 100% D.I.Y-kit :-)
PostPosted: Thu Dec 02, 2010 3:03 pm 

Joined: Sat Oct 29, 2005 9:54 pm
Posts: 65
What I've been using (since before you DIY kit was available) is mencoder to convert AVIs to 'Y8' format. These are a solitary files containing Y, U, and V frames, scaled and sampled at the correct frequency. The Y frames are easily converted to 16 gray levels.

For color movies I have to convert YUV to RGB. I originally used the floating point algorithm described here -> http://en.wikipedia.org/wiki/YUV but decided to try the 'bit shifting algorithm" since it's well suited to Action. It's much faster than BASIC and in Atari800 at full speed the conversion time is almost reasonable.

Eventually I would like to convert my tools to C (but that would mean I would have to learn C ;) ) and do everything in linux.

This method is probably more cumbersome and slower than using individual BMP files but I prefer the projects to be in just handful of files, easier to archive to DVD (which this time I will be more diligent about doing).

I'm sure my problem is a coding error but I know I'm getting good data for all three color planes. I have to be doing something wrong while packing the data, 4 pixels to a byte, or while writing the data back to disk.

I'll figure it out (eventually).

Thanks for your tips, your tools, and your MyIDE, of course.

-Steve Sheppard


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 Post subject: Re:
PostPosted: Fri Dec 03, 2010 8:05 pm 

Joined: Sat Oct 29, 2005 9:54 pm
Posts: 65
mr-atari wrote:
Updates DIY kit.

All programs run on the emulator (with assembler)!
set H: to your working directory.
type LOAD#H:name.ext [enter] to load the program
BUG [enter] to enter the debugger
G8000 [enter] or G2400 [enter] to run the program


2 min. demo included (GuitarHero episode from southpark)

Converting input files:
ATARI.AVI, 24 bit 8.333 fps uncompressed 128x64 pixel pc-avi-file
ATARI.SND, 8 bit 8.533 Hz unsigned pc-pcm-file (wave form)
Converted output files:
ATARI.RGB
ATARI.RAW

To view the video:
VIEWERE.OBJ, for emulator set at 200% (about 1 Ghz will do fine)
VIEWERE1.OBJ, for emulator set at 100% (needs faster pc)

Video conversion steps:
set output to 128x64 pixels
set fps at 50/3 (=8.333)
clip frame to 2:1 ratio
select source-range
increase gamma on dark movies
output as uncompressed 24bit ATARI.AVI

Audio converstion steps:
resamp to 8533 Hz
lowpass filter <4250 Hz
highpass filter >100 Hz
maximize
amplify (if needed more then 1 time to remove high dynamics)
baselinecorrection
save as 8bit unsigned ATARI.SND
After stumbling with my own conversions I finally got around to trying your DIY kit. Unfortunately, avi2rgb.obj isn't doing anything more than creating the file ATARI.RGB on my H: drive.

I think I'm creating the correct kind of uncompressed AVI. I used mencoder to scale and resample videos at 8.333 fps. Mencoder is also stripping away the audio. I then used ffmpeg to transcode the video (from divx) to BGR24 like this, ffmpeg -i myvid.avi -vcodec bmp ATARI.AVI

-Steve


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 Post subject: Re: Atari 8 bit moviez less then 100% D.I.Y-kit :-)
PostPosted: Sat Dec 04, 2010 12:20 pm 
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Joined: Sun Nov 02, 2003 8:15 am
Posts: 1549
Location: netherlands
Strange, the avi2rgb looks for the BMP-header with 128x64 pixels.
When found: converts them to A8-frames.

So when to output file is empty, there were no BMP's in the AVI.

I use: tmpgenc

Quote:
Video conversion steps:
set output to 128x64 pixels
set fps at 50/3 (=8.333)
clip frame to 2:1 ratio
select source-range
increase gamma on dark movies
output as uncompressed 24bit ATARI.AVI



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