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/*
Quicktime Animation (RLE) Decoder for MPlayer
(C) 2001 Mike Melanson
*/
#include "config.h"
#include "bswap.h"
#define BE_16(x) (be2me_16(*(unsigned short *)(x)))
#define BE_32(x) (be2me_32(*(unsigned int *)(x)))
// 256 RGB entries; 25% of these bytes will be unused, but it's faster
// to index 4-byte entries
static unsigned char palette[256 * 4];
void qt_decode_rle24(
unsigned char *encoded,
int encoded_size,
unsigned char *decoded,
int width,
int height,
int bytes_per_pixel)
{
int stream_ptr;
int header;
int start_line;
int lines_to_change;
signed char rle_code;
int row_ptr, pixel_ptr;
int row_inc = bytes_per_pixel * width;
unsigned char r, g, b;
// check if this frame is even supposed to change
if (encoded_size < 8)
return;
// start after the chunk size
stream_ptr = 4;
// fetch the header
header = BE_16(&encoded[stream_ptr]);
stream_ptr += 2;
// if a header is present, fetch additional decoding parameters
if (header & 0x0008)
{
start_line = BE_16(&encoded[stream_ptr]);
stream_ptr += 4;
lines_to_change = BE_16(&encoded[stream_ptr]);
stream_ptr += 4;
}
else
{
start_line = 0;
lines_to_change = height;
}
row_ptr = row_inc * start_line;
while (lines_to_change--)
{
pixel_ptr = row_ptr + ((encoded[stream_ptr++] - 1) * bytes_per_pixel);
while ((rle_code = (signed char)encoded[stream_ptr++]) != -1)
{
if (rle_code == 0)
// there's another skip code in the stream
pixel_ptr += ((encoded[stream_ptr++] - 1) * bytes_per_pixel);
else if (rle_code < 0)
{
// decode the run length code
rle_code = -rle_code;
r = encoded[stream_ptr++];
g = encoded[stream_ptr++];
b = encoded[stream_ptr++];
while (rle_code--)
{
decoded[pixel_ptr++] = b;
decoded[pixel_ptr++] = g;
decoded[pixel_ptr++] = r;
if (bytes_per_pixel == 4)
pixel_ptr++;
}
}
else
{
// copy pixels directly to output
while (rle_code--)
{
decoded[pixel_ptr++] = encoded[stream_ptr + 2];
decoded[pixel_ptr++] = encoded[stream_ptr + 1];
decoded[pixel_ptr++] = encoded[stream_ptr + 0];
stream_ptr += 3;
if (bytes_per_pixel == 4)
pixel_ptr++;
}
}
}
row_ptr += row_inc;
}
}
void qt_decode_rle(
unsigned char *encoded,
int encoded_size,
unsigned char *decoded,
int width,
int height,
int encoded_bpp,
int bytes_per_pixel)
{
switch (encoded_bpp)
{
case 24:
qt_decode_rle24(
encoded,
encoded_size,
decoded,
width,
height,
bytes_per_pixel);
break;
}
}
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