Re: "1-Hit Wonders"

On Thu, 25 Mar 2004, Jim Leonard wrote:

> Mike Melanson wrote:
> >   "1-Hit Wonder" Multimedia File Formats
>
> Friggin' awesome.  You are a machine!

	Not really, I just got bored with the other documentation projects
I was working on yesterday (VP3, SVQ3/H.264).

> Chronomaster:
> "  0070    apparently a palette chunk, 0x300 (768) bytes, and each
>            component is 8 bits (not 6 bits, like VGA palettes are
>            normally stored)"
>
> Actually, if you used VESA, it would indeed take and display properly an 8-bit
> palette.  If the game loaded Scitech's Display Doctor automatically, that was
> a good chance it relied on VESA to handle the video.  Since it costs nothing
> to store the actual 8-bit palette (you just SHR 2 if you use real VGA palette
> registers), I think many if not most companies did this.  I sure did.

	8-bit palette ranges are actually pretty rare, in my experience.
Some FLIC files were 6-bit, while others were 8-bit. Quake II .cin was
6-bit (supposed to be, anyway; found a 8-bit file once). Interplay MVE is
6-bit which is odd in light of your VESA comments since many of these
files were fairly hi-res (up to 640x480). Westwood VQA and Sierra VMD also
use 6-bit ranges. And 3/6 of those 1-hit wonder formats were 6-bit.

	Then there was the MVE format from Wing Commander III...the color
system on that one defies explanation.

> Novastorm:
>
> "
>    sample rate = 256 - (100000 / (signed) divisor byte)
>
>    0xC1 = -63
>
>    sample rate = 256 - (1000000 / -63) = 16129 Hz
> "
>
> Hold it, which one is the right forumla?

	Good catch. It's supposed to be the 1 million (6 0s).

> "The media frames follow the header. Each frame is packaged inside a
> chunk with the fourcc 'IVAS' (probably I. Video & Sound, where 'I' is
> presumably the same 'I' in 'BF&I'). "
>
> Actually, the I is most likely "interleaved", as in "Interleaved Video and Sound".

	Hmm, I like that better. Thanks...
--
	-Mike Melanson


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