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R43 video demo

Posted: Tue Jul 18, 2023 6:45 am
by Ed Minchau
This video is at 10 frames per second, 160 by 40 pixels. VSCALE of $20 and HSCALE of $13 stretches this image to an aspect ratio of about 2.35 to 1, the widescreen aspect ratio. The audio is 16 bit mono at 12970 Hz, so the PCM audio rate is $22. The audio and video data are interleaved in the BENH.DAT file; 1/10th of a second (2594 bytes) of audio followed by one video frame (6400 bytes), over and over. The AFLOW interrupt triggers the pushing of 2594 bytes of audio from VRAM to the PCM audio data line, followed by the next audio sample load to VRAM, then the next frame of video, and then the switch from the old frame to the new frame (just by changing the layer 0 tilemap location). There is a single palette for the whole video, which was created for the Wolfenstein 3D artwork for another project, and which I'm starting to think of as a "magic palette".
BENH.zip
(14.19 MiB) Downloaded 448 times
just LOAD"BENHUR.PRG",8 and RUN

Try It Now!
hmm. for some reason the Try It Now link isn't working. Did any of you who downloaded get this to work?

Re: R43 video demo

Posted: Tue Jul 18, 2023 3:26 pm
by badmai
Very cool, worked for me. (not the try it now)

I've been working on video playback too, still trying to find to bandwidth limits...so mine is not as good, only 80 x 60 15fps
to stay on topic, I did a Ben Hur clip :)

my converter shows this:
Video Size: 11467200
Total Frames: 2389
Bytes per Frame: 4800
Audio Size: 1946870
Bytes per Frame: 814

Re: R43 video demo

Posted: Tue Jul 18, 2023 4:53 pm
by kelli217
It's pretty good. Seems to not always quite be fast enough at loading the data? Occasional corrupted frames and accompanying static noises. Example image attached.
BenHur-corruptedframe.png
BenHur-corruptedframe.png (16.68 KiB) Viewed 5819 times

Re: R43 video demo

Posted: Tue Jul 18, 2023 5:03 pm
by Ed Minchau
Yeah, this is pretty much running the X16 at maximum, so if you've got any other programs open the emulator might not keep up. I noticed the same thing when opening Opera while the video clip was running. Or, I might be pushing just a little too much data through the pipe and could need to reduce the vertical resolution a bit. I'm interested to hear from people who have the actual machine if it works for them.

Re: R43 video demo

Posted: Tue Jul 18, 2023 5:13 pm
by Ed Minchau
badmai wrote: Tue Jul 18, 2023 3:26 pm Very cool, worked for me. (not the try it now)

I've been working on video playback too, still trying to find to bandwidth limits...so mine is not as good, only 80 x 60 15fps
to stay on topic, I did a Ben Hur clip :)

my converter shows this:
Video Size: 11467200
Total Frames: 2389
Bytes per Frame: 4800
Audio Size: 1946870
Bytes per Frame: 814
That worked pretty well, but remember to use all capital letters in your filenames. Also, you don't need all 60 rows; it looks like about 13 rows at the top and bottom are black, so you could keep it that way and only have about 34 rows of data, reducing the number of bytes per frame to around 2720. That could get you 20 or maybe even 30 frames per second.

Re: R43 video demo

Posted: Mon Jul 24, 2023 12:10 am
by ahenry3068
I have a challenge for you. (Though it could run afoul of Copyright Law)....

Do this same project for "THRILLER"

Re: R43 video demo

Posted: Wed Jul 26, 2023 10:29 pm
by Ed Minchau
All of these run afoul of copyright law. If I post the results to YouTube it gets flagged, probably because of the audio. I really only do these video demos to explore the limits of VERA.

I'm thinking that there's a way to get better results, or at least a higher frame rate, by using the double PETSCII technique, perhaps with a custom character set.

Re: R43 video demo

Posted: Thu Aug 03, 2023 12:15 am
by ahenry3068
Im in research Mode

The reserch is to just show FLI
s
On x16

Re: R43 video demo

Posted: Thu Aug 03, 2023 2:11 am
by kelli217
Ed Minchau wrote: Wed Jul 26, 2023 10:29 pm All of these run afoul of copyright law. If I post the results to YouTube it gets flagged, probably because of the audio. I really only do these video demos to explore the limits of VERA.

I'm thinking that there's a way to get better results, or at least a higher frame rate, by using the double PETSCII technique, perhaps with a custom character set.
That would be great if you can get it to work.