mpv/qtsmc.c

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/*
Apple Graphics (SMC) Decoder for MPlayer
by Mike Melanson
Special thanks for Roberto Togni <rtogni@bresciaonline.it> for
tracking down the final, nagging bugs.
The description of the decoding algorithm can be found here:
http://www.pcisys.net/~melanson/codecs/
*/
#include <stdlib.h>
#include "config.h"
#include "bswap.h"
#include "mp_msg.h"
#define BE_16(x) (be2me_16(*(unsigned short *)(x)))
#define BE_32(x) (be2me_32(*(unsigned int *)(x)))
#define COLORS_PER_TABLE 256
#define BYTES_PER_COLOR 4
#define CPAIR 2
#define CQUAD 4
#define COCTET 8
static unsigned char *color_pairs;
static unsigned char *color_quads;
static unsigned char *color_octets;
static int color_pair_index;
static int color_quad_index;
static int color_octet_index;
static int smc_initialized;
// returns 0 if successfully initialized (enough memory was available),
// non-zero on failure
int qt_init_decode_smc(void)
{
// be pessimistic to start
smc_initialized = 0;
// allocate memory for the 3 palette tables
if ((color_pairs = (unsigned char *)malloc(
COLORS_PER_TABLE * BYTES_PER_COLOR * 2)) == 0)
return 1;
if ((color_quads = (unsigned char *)malloc(
COLORS_PER_TABLE * BYTES_PER_COLOR * 4)) == 0)
return 1;
if ((color_octets = (unsigned char *)malloc(
COLORS_PER_TABLE * BYTES_PER_COLOR * 8)) == 0)
return 1;
// if execution got this far, initialization succeeded
smc_initialized = 1;
return 0;
}
#define GET_BLOCK_COUNT \
(opcode & 0x10) ? (1 + encoded[stream_ptr++]) : 1 + (opcode & 0x0F);
#define ADVANCE_BLOCK() \
{ \
pixel_ptr += block_x_inc; \
if (pixel_ptr >= byte_width) \
{ \
pixel_ptr = 0; \
row_ptr += block_y_inc * 4; \
} \
total_blocks--; \
if (total_blocks < 0) \
{ \
mp_msg(MSGT_DECVIDEO, MSGL_WARN, "block counter just went negative (this should not happen)\n"); \
return; \
} \
}
void qt_decode_smc(
unsigned char *encoded,
int encoded_size,
unsigned char *decoded,
int pixel_width,
int pixel_height,
unsigned char *palette_map,
int bytes_per_pixel)
{
int i;
int stream_ptr = 0;
int chunk_size;
unsigned char opcode;
int n_blocks;
unsigned int color_flags;
unsigned int color_flags_a;
unsigned int color_flags_b;
unsigned int flag_mask;
int byte_width = pixel_width * bytes_per_pixel; // width of a row in bytes
int byte_height = pixel_height * byte_width; // max image size, basically
int row_ptr = 0;
int pixel_ptr = 0;
int pixel_x, pixel_y;
int row_inc = bytes_per_pixel * (pixel_width - 4);
int block_x_inc = bytes_per_pixel * 4;
int block_y_inc = bytes_per_pixel * pixel_width;
int block_ptr;
int prev_block_ptr;
int prev_block_ptr1, prev_block_ptr2;
int prev_block_flag;
int total_blocks;
int color_table_index; // indexes to color pair, quad, or octet tables
int color_index; // indexes into palette map
if (!smc_initialized)
return;
// reset color tables
color_pair_index = 0;
color_quad_index = 0;
color_octet_index = 0;
chunk_size = BE_32(&encoded[stream_ptr]) & 0x00FFFFFF;
stream_ptr += 4;
if (chunk_size != encoded_size)
mp_msg(MSGT_DECVIDEO, MSGL_WARN, "MOV chunk size != encoded chunk size; using MOV chunk size\n");
chunk_size = encoded_size;
total_blocks = (pixel_width * pixel_height) / (4 * 4);
// traverse through the blocks
while (total_blocks)
{
// sanity checks
// make sure stream ptr hasn't gone out of bounds
if (stream_ptr > chunk_size)
{
mp_msg(MSGT_DECVIDEO, MSGL_ERR,
"SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",
stream_ptr, chunk_size);
return;
}
// make sure the row pointer hasn't gone wild
if (row_ptr >= byte_height)
{
mp_msg(MSGT_DECVIDEO, MSGL_ERR,
"SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
row_ptr, byte_height);
return;
}
opcode = encoded[stream_ptr++];
switch (opcode & 0xF0)
{
// skip n blocks
case 0x00:
case 0x10:
n_blocks = GET_BLOCK_COUNT;
while (n_blocks--)
ADVANCE_BLOCK();
break;
// repeat last block n times
case 0x20:
case 0x30:
n_blocks = GET_BLOCK_COUNT;
// sanity check
if ((row_ptr == 0) && (pixel_ptr == 0))
{
mp_msg(MSGT_DECVIDEO, MSGL_WARN,
"encountered repeat block opcode (%02X) but no blocks rendered yet\n",
opcode & 0xF0);
break;
}
// figure out where the previous block started
if (pixel_ptr == 0)
prev_block_ptr1 = (row_ptr - block_y_inc * 4) +
byte_width - block_x_inc;
else
prev_block_ptr1 = row_ptr + pixel_ptr - block_x_inc;
while (n_blocks--)
{
block_ptr = row_ptr + pixel_ptr;
prev_block_ptr = prev_block_ptr1;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
decoded[block_ptr++] = decoded[prev_block_ptr++];
decoded[block_ptr++] = decoded[prev_block_ptr++];
decoded[block_ptr++] = decoded[prev_block_ptr++];
if (bytes_per_pixel == 4) /* 32bpp */
{
block_ptr++;
prev_block_ptr++;
}
}
block_ptr += row_inc;
prev_block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
// repeat previous pair of blocks n times
case 0x40:
case 0x50:
n_blocks = GET_BLOCK_COUNT;
n_blocks *= 2;
// sanity check
if ((row_ptr == 0) && (pixel_ptr < 2 * block_x_inc))
{
mp_msg(MSGT_DECVIDEO, MSGL_WARN,
"encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
opcode & 0xF0);
break;
}
// figure out where the previous 2 blocks started
if (pixel_ptr == 0)
prev_block_ptr1 = (row_ptr - block_y_inc * 4) +
byte_width - block_x_inc * 2;
else if (pixel_ptr == block_x_inc)
prev_block_ptr1 = (row_ptr - block_y_inc * 4) +
byte_width - block_x_inc;
else
prev_block_ptr1 = row_ptr + pixel_ptr - block_x_inc * 2;
if (pixel_ptr == 0)
prev_block_ptr2 = (row_ptr - block_y_inc * 4) +
(byte_width - block_x_inc);
else
prev_block_ptr2 = row_ptr + pixel_ptr - block_x_inc;
prev_block_flag = 0;
while (n_blocks--)
{
block_ptr = row_ptr + pixel_ptr;
if (prev_block_flag)
prev_block_ptr = prev_block_ptr2;
else
prev_block_ptr = prev_block_ptr1;
prev_block_flag = !prev_block_flag;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
decoded[block_ptr++] = decoded[prev_block_ptr++];
decoded[block_ptr++] = decoded[prev_block_ptr++];
decoded[block_ptr++] = decoded[prev_block_ptr++];
if (bytes_per_pixel == 4) /* 32bpp */
{
block_ptr++;
prev_block_ptr++;
}
}
block_ptr += row_inc;
prev_block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
// 1-color block encoding
case 0x60:
case 0x70:
n_blocks = GET_BLOCK_COUNT;
color_index = encoded[stream_ptr++] * 4;
while (n_blocks--)
{
block_ptr = row_ptr + pixel_ptr;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
decoded[block_ptr++] = palette_map[color_index + 0];
decoded[block_ptr++] = palette_map[color_index + 1];
decoded[block_ptr++] = palette_map[color_index + 2];
if (bytes_per_pixel == 4) /* 32bpp */
block_ptr++;
}
block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
// 2-color block encoding
case 0x80:
case 0x90:
n_blocks = (opcode & 0x0F) + 1;
// figure out which color pair to use to paint the 2-color block
if ((opcode & 0xF0) == 0x80)
{
// fetch the next 2 colors from bytestream and store in next
// available entry in the color pair table
for (i = 0; i < CPAIR; i++)
{
color_index = encoded[stream_ptr++] * BYTES_PER_COLOR;
color_table_index = CPAIR * BYTES_PER_COLOR * color_pair_index +
(i * BYTES_PER_COLOR);
color_pairs[color_table_index + 0] = palette_map[color_index + 0];
color_pairs[color_table_index + 1] = palette_map[color_index + 1];
color_pairs[color_table_index + 2] = palette_map[color_index + 2];
}
// this is the base index to use for this block
color_table_index = CPAIR * BYTES_PER_COLOR * color_pair_index;
color_pair_index++;
if (color_pair_index == COLORS_PER_TABLE)
color_pair_index = 0;
}
else
color_table_index = CPAIR * BYTES_PER_COLOR * encoded[stream_ptr++];
while (n_blocks--)
{
color_flags = BE_16(&encoded[stream_ptr]);
stream_ptr += 2;
flag_mask = 0x8000;
block_ptr = row_ptr + pixel_ptr;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
if (color_flags & flag_mask)
color_index = color_table_index + BYTES_PER_COLOR;
else
color_index = color_table_index;
flag_mask >>= 1;
decoded[block_ptr++] = color_pairs[color_index + 0];
decoded[block_ptr++] = color_pairs[color_index + 1];
decoded[block_ptr++] = color_pairs[color_index + 2];
if (bytes_per_pixel == 4) /* 32bpp */
block_ptr++;
}
block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
// 4-color block encoding
case 0xA0:
case 0xB0:
n_blocks = (opcode & 0x0F) + 1;
// figure out which color quad to use to paint the 4-color block
if ((opcode & 0xF0) == 0xA0)
{
// fetch the next 4 colors from bytestream and store in next
// available entry in the color quad table
for (i = 0; i < CQUAD; i++)
{
color_index = encoded[stream_ptr++] * BYTES_PER_COLOR;
color_table_index = CQUAD * BYTES_PER_COLOR * color_quad_index +
(i * BYTES_PER_COLOR);
color_quads[color_table_index + 0] = palette_map[color_index + 0];
color_quads[color_table_index + 1] = palette_map[color_index + 1];
color_quads[color_table_index + 2] = palette_map[color_index + 2];
}
// this is the base index to use for this block
color_table_index = CQUAD * BYTES_PER_COLOR * color_quad_index;
color_quad_index++;
if (color_quad_index == COLORS_PER_TABLE)
color_quad_index = 0;
}
else
color_table_index = CQUAD * BYTES_PER_COLOR * encoded[stream_ptr++];
while (n_blocks--)
{
color_flags = BE_32(&encoded[stream_ptr]);
stream_ptr += 4;
// flag mask actually acts as a bit shift count here
flag_mask = 30;
block_ptr = row_ptr + pixel_ptr;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
color_index = color_table_index + (BYTES_PER_COLOR *
((color_flags >> flag_mask) & 0x03));
flag_mask -= 2;
decoded[block_ptr++] = color_quads[color_index + 0];
decoded[block_ptr++] = color_quads[color_index + 1];
decoded[block_ptr++] = color_quads[color_index + 2];
if (bytes_per_pixel == 4) /* 32bpp */
block_ptr++;
}
block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
// 8-color block encoding
case 0xC0:
case 0xD0:
n_blocks = (opcode & 0x0F) + 1;
// figure out which color octet to use to paint the 8-color block
if ((opcode & 0xF0) == 0xC0)
{
// fetch the next 8 colors from bytestream and store in next
// available entry in the color octet table
for (i = 0; i < COCTET; i++)
{
color_index = encoded[stream_ptr++] * BYTES_PER_COLOR;
color_table_index = COCTET * BYTES_PER_COLOR * color_octet_index +
(i * BYTES_PER_COLOR);
color_octets[color_table_index + 0] = palette_map[color_index + 0];
color_octets[color_table_index + 1] = palette_map[color_index + 1];
color_octets[color_table_index + 2] = palette_map[color_index + 2];
}
// this is the base index to use for this block
color_table_index = COCTET * BYTES_PER_COLOR * color_octet_index;
color_octet_index++;
if (color_octet_index == COLORS_PER_TABLE)
color_octet_index = 0;
}
else
color_table_index = COCTET * BYTES_PER_COLOR * encoded[stream_ptr++];
while (n_blocks--)
{
/*
For this input:
01 23 45 67 89 AB
This is the output:
flags_a = xx012456, flags_b = xx89A37B
*/
// build the color flags
color_flags_a = color_flags_b = 0;
color_flags_a =
(encoded[stream_ptr + 0] << 16) |
((encoded[stream_ptr + 1] & 0xF0) << 8) |
((encoded[stream_ptr + 2] & 0xF0) << 4) |
((encoded[stream_ptr + 2] & 0x0F) << 4) |
((encoded[stream_ptr + 3] & 0xF0) >> 4);
color_flags_b =
(encoded[stream_ptr + 4] << 16) |
((encoded[stream_ptr + 5] & 0xF0) << 8) |
((encoded[stream_ptr + 1] & 0x0F) << 8) |
((encoded[stream_ptr + 3] & 0x0F) << 4) |
(encoded[stream_ptr + 5] & 0x0F);
stream_ptr += 6;
color_flags = color_flags_a;
// flag mask actually acts as a bit shift count here
flag_mask = 21;
block_ptr = row_ptr + pixel_ptr;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
// reload flags at third row (iteration pixel_y == 2)
if (pixel_y == 2)
{
color_flags = color_flags_b;
flag_mask = 21;
}
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
color_index = color_table_index + (BYTES_PER_COLOR *
((color_flags >> flag_mask) & 0x07));
flag_mask -= 3;
decoded[block_ptr++] = color_octets[color_index + 0];
decoded[block_ptr++] = color_octets[color_index + 1];
decoded[block_ptr++] = color_octets[color_index + 2];
if (bytes_per_pixel == 4) /* 32bpp */
block_ptr++;
}
block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
// 16-color block encoding (every pixel is a different color)
case 0xE0:
n_blocks = (opcode & 0x0F) + 1;
while (n_blocks--)
{
block_ptr = row_ptr + pixel_ptr;
for (pixel_y = 0; pixel_y < 4; pixel_y++)
{
for (pixel_x = 0; pixel_x < 4; pixel_x++)
{
color_index = encoded[stream_ptr++] * BYTES_PER_COLOR;
decoded[block_ptr++] = palette_map[color_index + 0];
decoded[block_ptr++] = palette_map[color_index + 1];
decoded[block_ptr++] = palette_map[color_index + 2];
if (bytes_per_pixel == 4) /* 32bpp */
block_ptr++;
}
block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
case 0xF0:
mp_msg(MSGT_DECVIDEO, MSGL_HINT, "0xF0 opcode seen in SMC chunk (MPlayer developers would like to know)\n");
break;
}
}
}