[FFmpeg-soc] BFI

[Mike Melanson]

Sisir Koppaka wrote:
> The BFI wiki page says(http://wiki.multimedia.cx/index.php?title=BFI) :
> 
>  bytes 60-827   ( +3C) 256 RGB triplets (6-bit VGA palette values)
> 
>  and also,
> The video always encoded as palettized, 8-bit data.
> 
> How are these two the same? Yes, 8 bit data corresponds to 256 RGB triplets
> but what is the '6-bit VGA palette values'? I'm finding some trouble here
> handling the decoding, can anyone please help me with this?

A decoded picture is width x height pixels. Each pixel is 8 bits, or 1
byte. That's where the "8-bit data" part comes from.

There is a 256-color palette. Each pixel (which is an 8-bit value,
0-255) points to one of those 256 colors. Each color is comprised of a
red, green, and blue value. Each R, G, and B value has a 6-bit range
(0-63). That's where the "6-bit VGA palette values" part comes from.
More background on that here:

  http://wiki.multimedia.cx/index.php?title=VGA

Before you pass the RGB components to FFmpeg, you will need to scale
them to be 8-bit components.

-- 
	-Mike Melanson