Author Archives: Multimedia Mike

FATE Building Blocks

For 2 years, I’ve been wrangling with the overall architecture of the FATE system. Right now, there’s a primary fate-script.py program that manages building and testing on FATE installations that is sorely in need of many upgrades. Then there is fate-client.py which is a somewhat lighter-weight testing program. I have long wanted to merge the 2 scripts but could never settle on how to do it. At the base level, should the script assume that it’s operating in continuous build/test mode (a la fate-script.py) or single-shot test mode (a la fate-client.py) by default? Or neither? Should it force the user to specify a mess of command line options?

I had an epiphany recently while reading the documentation for Python’s standard (as of v2.3) optparse module, specifically the section entitled “What are options for?”

Options are used to provide extra information to tune or customize the execution of a program. In case it wasn’t clear, options are usually optional. A program should be able to run just fine with no options whatsoever… Lots of people want their programs to have ‘required options’. Think about it. If it’s required, then it’s not optional!

This led me to consider the possibility of a FATE script that could do something without any options and then build from there.

Default Operation Continue reading →

Google Funding VP3 On ARM

Some news is making the rounds that Google is funding ARM improvements for the Theora video decoder. It gives the free software faithful renewed hope. However, reading this news makes me wonder: Doesn’t FFmpeg already have ARM optimizations for Theora? In fact, it does, as indicated by the existence of the file libavcodec/arm/vp3dsp_neon.S. This has optimized IDCT transform/get/put and loop filter functions for NEON instruction sets. I know there are several different types of SIMD for ARM chips and I don’t know if NEON is the most common variety.

The most pressing reason for funding this effort is, of course, license purity.

Intentional Time-Consuming Work

A woman sat down across from me on the train, pulled out her knitting needles and went to work on what appeared to be a scarf. I briefly pondered the fact that she chose to busy herself with constructing a scarf the hard way when it’s obviously faster and cheaper to buy a scarf off the shelf.



Then I immediately pondered how many of my personal programming projects fall into this same category of wheels that don’t need to be reinvented. There are still plenty of projects I want to take on that would surely serve no practical purpose in the grand scheme of things, particularly when evaluated against what I could be spending my time on.

Video game console programming springs immediately to mind. I was interested in Sega Dreamcast programming long after the system had become obsolete. For that matter, I’m still interested in Sony PlayStation 3 programming, even though that community is about to be driven underground. I have long been interested in the technical aspects of the 8-bit Nintendo Entertainment System (NES) and have always wanted to write software for that console as well. A few years ago, I even purchased RetroUSB’s PowerPak, a CompactFlash-based game cartridge, probably the easiest method for testing code on an actual system. Mercifully, I recently gave away that item (and the console, an SNES-style top loader), so that’s one less area on which I can waste my spare dev time. I still have the DC and the PS3, though.

My FFmpeg colleagues should be pleased to hear that I do try to make my FATE work a priority above these arguably more frivolous pursuits.

Kega Video In FFmpeg

Thanks to Daniel Verkamp for contributing a Kega video (KGV1) decoder to FFmpeg. I was about to demand samples for testing until I looked up what Kega is — a Sega game console emulator — when I realized that it would be more fun to create my own (be advised that only the Windows version of Kega presently supports the AVI encoding option). Then I looked up the Wiki page and realized that there is, in fact, one sample on record at the archive. Well, I went ahead and made my own sample anyway. I used the mountainside attract-mode scene from the Genesis game Strider, one of my favorite sequences in any video game. It’s in the samples directory.



I am holding off on adding a FATE test; there’s still an endian issue (PPC configs disagree with x86 configs). I’m also a little puzzled as to why FFplay insists on playing the video as 320×240 even though the video is encoded as 640×480. For that matter, I’m also bewildered trying to understand why Kega renders video as 640×480 by default; that’s not a native resolution for any of its emulated consoles.