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ffmpeg/libavcodec/smc.c

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/*
* Quicktime Graphics (SMC) Video Decoder
* Copyright (C) 2003 the ffmpeg project
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file libavcodec/smc.c
* QT SMC Video Decoder by Mike Melanson (melanson@pcisys.net)
* For more information about the SMC format, visit:
* http://www.pcisys.net/~melanson/codecs/
*
* The SMC decoder outputs PAL8 colorspace data.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#define CPAIR 2
#define CQUAD 4
#define COCTET 8
#define COLORS_PER_TABLE 256
typedef struct SmcContext {
AVCodecContext *avctx;
AVFrame frame;
const unsigned char *buf;
int size;
/* SMC color tables */
unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];
unsigned char color_quads[COLORS_PER_TABLE * CQUAD];
unsigned char color_octets[COLORS_PER_TABLE * COCTET];
} SmcContext;
#define GET_BLOCK_COUNT() \
(opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);
#define ADVANCE_BLOCK() \
{ \
pixel_ptr += 4; \
if (pixel_ptr >= width) \
{ \
pixel_ptr = 0; \
row_ptr += stride * 4; \
} \
total_blocks--; \
if (total_blocks < 0) \
{ \
av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
return; \
} \
}
static void smc_decode_stream(SmcContext *s)
{
int width = s->avctx->width;
int height = s->avctx->height;
int stride = s->frame.linesize[0];
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;
unsigned char *pixels = s->frame.data[0];
int image_size = height * s->frame.linesize[0];
int row_ptr = 0;
int pixel_ptr = 0;
int pixel_x, pixel_y;
int row_inc = stride - 4;
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 pixel;
int color_pair_index = 0;
int color_quad_index = 0;
int color_octet_index = 0;
/* make the palette available */
memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
if (s->avctx->palctrl->palette_changed) {
s->frame.palette_has_changed = 1;
s->avctx->palctrl->palette_changed = 0;
}
chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
stream_ptr += 4;
if (chunk_size != s->size)
av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
chunk_size, s->size);
chunk_size = s->size;
total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 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) {
av_log(s->avctx, AV_LOG_INFO, "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 >= image_size) {
av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
row_ptr, image_size);
return;
}
opcode = s->buf[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)) {
av_log(s->avctx, AV_LOG_INFO, "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 - s->avctx->width * 4) + s->avctx->width - 4;
else
prev_block_ptr1 = row_ptr + pixel_ptr - 4;
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++) {
pixels[block_ptr++] = pixels[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 * 4)) {
av_log(s->avctx, AV_LOG_INFO, "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 - s->avctx->width * 4) +
s->avctx->width - 4 * 2;
else if (pixel_ptr == 4)
prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;
else
prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;
if (pixel_ptr == 0)
prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;
else
prev_block_ptr2 = row_ptr + pixel_ptr - 4;
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++) {
pixels[block_ptr++] = pixels[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();
pixel = s->buf[stream_ptr++];
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++) {
pixels[block_ptr++] = pixel;
}
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++) {
pixel = s->buf[stream_ptr++];
color_table_index = CPAIR * color_pair_index + i;
s->color_pairs[color_table_index] = pixel;
}
/* this is the base index to use for this block */
color_table_index = CPAIR * color_pair_index;
color_pair_index++;
/* wraparound */
if (color_pair_index == COLORS_PER_TABLE)
color_pair_index = 0;
} else
color_table_index = CPAIR * s->buf[stream_ptr++];
while (n_blocks--) {
color_flags = AV_RB16(&s->buf[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)
pixel = color_table_index + 1;
else
pixel = color_table_index;
flag_mask >>= 1;
pixels[block_ptr++] = s->color_pairs[pixel];
}
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++) {
pixel = s->buf[stream_ptr++];
color_table_index = CQUAD * color_quad_index + i;
s->color_quads[color_table_index] = pixel;
}
/* this is the base index to use for this block */
color_table_index = CQUAD * color_quad_index;
color_quad_index++;
/* wraparound */
if (color_quad_index == COLORS_PER_TABLE)
color_quad_index = 0;
} else
color_table_index = CQUAD * s->buf[stream_ptr++];
while (n_blocks--) {
color_flags = AV_RB32(&s->buf[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++) {
pixel = color_table_index +
((color_flags >> flag_mask) & 0x03);
flag_mask -= 2;
pixels[block_ptr++] = s->color_quads[pixel];
}
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++) {
pixel = s->buf[stream_ptr++];
color_table_index = COCTET * color_octet_index + i;
s->color_octets[color_table_index] = pixel;
}
/* this is the base index to use for this block */
color_table_index = COCTET * color_octet_index;
color_octet_index++;
/* wraparound */
if (color_octet_index == COLORS_PER_TABLE)
color_octet_index = 0;
} else
color_table_index = COCTET * s->buf[stream_ptr++];
while (n_blocks--) {
/*
For this input of 6 hex bytes:
01 23 45 67 89 AB
Mangle it to this output:
flags_a = xx012456, flags_b = xx89A37B
*/
/* build the color flags */
color_flags_a =
((AV_RB16(s->buf + stream_ptr ) & 0xFFF0) << 8) |
(AV_RB16(s->buf + stream_ptr + 2) >> 4);
color_flags_b =
((AV_RB16(s->buf + stream_ptr + 4) & 0xFFF0) << 8) |
((s->buf[stream_ptr + 1] & 0x0F) << 8) |
((s->buf[stream_ptr + 3] & 0x0F) << 4) |
(s->buf[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++) {
pixel = color_table_index +
((color_flags >> flag_mask) & 0x07);
flag_mask -= 3;
pixels[block_ptr++] = s->color_octets[pixel];
}
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++) {
pixels[block_ptr++] = s->buf[stream_ptr++];
}
block_ptr += row_inc;
}
ADVANCE_BLOCK();
}
break;
case 0xF0:
av_log(s->avctx, AV_LOG_INFO, "0xF0 opcode seen in SMC chunk (contact the developers)\n");
break;
}
}
}
static av_cold int smc_decode_init(AVCodecContext *avctx)
{
SmcContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->pix_fmt = PIX_FMT_PAL8;
s->frame.data[0] = NULL;
return 0;
}
static int smc_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
SmcContext *s = avctx->priv_data;
s->buf = buf;
s->size = buf_size;
s->frame.reference = 1;
s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
if (avctx->reget_buffer(avctx, &s->frame)) {
av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
return -1;
}
smc_decode_stream(s);
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
/* always report that the buffer was completely consumed */
return buf_size;
}
static av_cold int smc_decode_end(AVCodecContext *avctx)
{
SmcContext *s = avctx->priv_data;
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
return 0;
}
AVCodec smc_decoder = {
"smc",
CODEC_TYPE_VIDEO,
CODEC_ID_SMC,
sizeof(SmcContext),
smc_decode_init,
NULL,
smc_decode_end,
smc_decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
};
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