Search the Community
Showing results for tags 'pcm audio'.
Now that the emulator loads files at the same speed as the actual hardware, I decided to revisit video. This one is from the opening scene to The Spy Who Loved Me, including one of the greatest stunts ever recorded on film. The video was extracted to bmp images, and those were compressed to 160x32 pixels, and then the closest color in a custom palette was found for each pixel. The color palette was not chosen for this video. It's a palette I'm using on another project, and most of the colors are based on the Wolfenstein 3D wall images. These images are stretched to the desired 2.35:1 widescreen aspect ratio by setting the HSCALE to $20 and the VSCALE to $0F. The sound file was recorded in Audacity as 16 bit mono at 12970 Hz, and then cut up into files consisting of a 2 byte header and 2594 bytes of PCM audio data each. There are 10 audio files played per second. The video is shown at 15 frames per second at 5 kb each, so that's about 100 kb per second being loaded from the SD card and pushed to VERA. This should work on the actual hardware. By the end of the video the audio and video are slightly out of sync, with the video lagging slightly. I could probably make the video and audio line up exactly if I dropped the video frame rate down to 12 frames per second, but that's getting into slideshow territory. I got the PCM audio figured out so that there's no bursts of static anymore; unfortunately the audio is so good that YouTube flagged it for copyright violation, even though the copyright owners do allow the use of it on YouTube. I'm attaching a zip file containing BOND.PRG and the BOND folder, as well as the metadata files in the META folder. If you unzip this into the same folder as the emulator, it should work for you if you type LOAD"BOND.PRG",8,1 RUN If you also have the META/L editor, changing the BASIC bootstrap to 1 SYS$0400 will load up the editor and metadata so you can look at the code. BOND.zip
This demo is made possible by loading data from file directly to VERA. Each frame is three files: an audio file, an image data file, and a palette file. 20 frames per second is 60 files per second, so this is one heck of a lot of files, nearly 16000 for a four and a half minute video. They only dreamed of doing this on an 8 bit computer in the 80s, but they didn't have @Frank van den Hoef or @Michael Steil videodemo.zip