2 * Quicktime Graphics (SMC) Video Decoder
3 * Copyright (C) 2003 the ffmpeg project
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * @file libavcodec/smc.c
24 * QT SMC Video Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the SMC format, visit:
26 * http://www.pcisys.net/~melanson/codecs/
28 * The SMC decoder outputs PAL8 colorspace data.
36 #include "libavutil/intreadwrite.h"
43 #define COLORS_PER_TABLE 256
45 typedef struct SmcContext {
47 AVCodecContext *avctx;
50 const unsigned char *buf;
53 /* SMC color tables */
54 unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];
55 unsigned char color_quads[COLORS_PER_TABLE * CQUAD];
56 unsigned char color_octets[COLORS_PER_TABLE * COCTET];
60 #define GET_BLOCK_COUNT() \
61 (opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);
63 #define ADVANCE_BLOCK() \
66 if (pixel_ptr >= width) \
69 row_ptr += stride * 4; \
72 if (total_blocks < 0) \
74 av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
79 static void smc_decode_stream(SmcContext *s)
81 int width = s->avctx->width;
82 int height = s->avctx->height;
83 int stride = s->frame.linesize[0];
89 unsigned int color_flags;
90 unsigned int color_flags_a;
91 unsigned int color_flags_b;
92 unsigned int flag_mask;
94 unsigned char *pixels = s->frame.data[0];
96 int image_size = height * s->frame.linesize[0];
100 int row_inc = stride - 4;
103 int prev_block_ptr1, prev_block_ptr2;
106 int color_table_index; /* indexes to color pair, quad, or octet tables */
109 int color_pair_index = 0;
110 int color_quad_index = 0;
111 int color_octet_index = 0;
113 /* make the palette available */
114 memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
115 if (s->avctx->palctrl->palette_changed) {
116 s->frame.palette_has_changed = 1;
117 s->avctx->palctrl->palette_changed = 0;
120 chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
122 if (chunk_size != s->size)
123 av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
124 chunk_size, s->size);
126 chunk_size = s->size;
127 total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);
129 /* traverse through the blocks */
130 while (total_blocks) {
132 /* make sure stream ptr hasn't gone out of bounds */
133 if (stream_ptr > chunk_size) {
134 av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",
135 stream_ptr, chunk_size);
138 /* make sure the row pointer hasn't gone wild */
139 if (row_ptr >= image_size) {
140 av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
141 row_ptr, image_size);
145 opcode = s->buf[stream_ptr++];
146 switch (opcode & 0xF0) {
150 n_blocks = GET_BLOCK_COUNT();
156 /* repeat last block n times */
159 n_blocks = GET_BLOCK_COUNT();
162 if ((row_ptr == 0) && (pixel_ptr == 0)) {
163 av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but no blocks rendered yet\n",
168 /* figure out where the previous block started */
171 (row_ptr - s->avctx->width * 4) + s->avctx->width - 4;
173 prev_block_ptr1 = row_ptr + pixel_ptr - 4;
176 block_ptr = row_ptr + pixel_ptr;
177 prev_block_ptr = prev_block_ptr1;
178 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
179 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
180 pixels[block_ptr++] = pixels[prev_block_ptr++];
182 block_ptr += row_inc;
183 prev_block_ptr += row_inc;
189 /* repeat previous pair of blocks n times */
192 n_blocks = GET_BLOCK_COUNT();
196 if ((row_ptr == 0) && (pixel_ptr < 2 * 4)) {
197 av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
202 /* figure out where the previous 2 blocks started */
204 prev_block_ptr1 = (row_ptr - s->avctx->width * 4) +
205 s->avctx->width - 4 * 2;
206 else if (pixel_ptr == 4)
207 prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;
209 prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;
212 prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;
214 prev_block_ptr2 = row_ptr + pixel_ptr - 4;
218 block_ptr = row_ptr + pixel_ptr;
220 prev_block_ptr = prev_block_ptr2;
222 prev_block_ptr = prev_block_ptr1;
223 prev_block_flag = !prev_block_flag;
225 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
226 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
227 pixels[block_ptr++] = pixels[prev_block_ptr++];
229 block_ptr += row_inc;
230 prev_block_ptr += row_inc;
236 /* 1-color block encoding */
239 n_blocks = GET_BLOCK_COUNT();
240 pixel = s->buf[stream_ptr++];
243 block_ptr = row_ptr + pixel_ptr;
244 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
245 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
246 pixels[block_ptr++] = pixel;
248 block_ptr += row_inc;
254 /* 2-color block encoding */
257 n_blocks = (opcode & 0x0F) + 1;
259 /* figure out which color pair to use to paint the 2-color block */
260 if ((opcode & 0xF0) == 0x80) {
261 /* fetch the next 2 colors from bytestream and store in next
262 * available entry in the color pair table */
263 for (i = 0; i < CPAIR; i++) {
264 pixel = s->buf[stream_ptr++];
265 color_table_index = CPAIR * color_pair_index + i;
266 s->color_pairs[color_table_index] = pixel;
268 /* this is the base index to use for this block */
269 color_table_index = CPAIR * color_pair_index;
272 if (color_pair_index == COLORS_PER_TABLE)
273 color_pair_index = 0;
275 color_table_index = CPAIR * s->buf[stream_ptr++];
278 color_flags = AV_RB16(&s->buf[stream_ptr]);
281 block_ptr = row_ptr + pixel_ptr;
282 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
283 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
284 if (color_flags & flag_mask)
285 pixel = color_table_index + 1;
287 pixel = color_table_index;
289 pixels[block_ptr++] = s->color_pairs[pixel];
291 block_ptr += row_inc;
297 /* 4-color block encoding */
300 n_blocks = (opcode & 0x0F) + 1;
302 /* figure out which color quad to use to paint the 4-color block */
303 if ((opcode & 0xF0) == 0xA0) {
304 /* fetch the next 4 colors from bytestream and store in next
305 * available entry in the color quad table */
306 for (i = 0; i < CQUAD; i++) {
307 pixel = s->buf[stream_ptr++];
308 color_table_index = CQUAD * color_quad_index + i;
309 s->color_quads[color_table_index] = pixel;
311 /* this is the base index to use for this block */
312 color_table_index = CQUAD * color_quad_index;
315 if (color_quad_index == COLORS_PER_TABLE)
316 color_quad_index = 0;
318 color_table_index = CQUAD * s->buf[stream_ptr++];
321 color_flags = AV_RB32(&s->buf[stream_ptr]);
323 /* flag mask actually acts as a bit shift count here */
325 block_ptr = row_ptr + pixel_ptr;
326 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
327 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
328 pixel = color_table_index +
329 ((color_flags >> flag_mask) & 0x03);
331 pixels[block_ptr++] = s->color_quads[pixel];
333 block_ptr += row_inc;
339 /* 8-color block encoding */
342 n_blocks = (opcode & 0x0F) + 1;
344 /* figure out which color octet to use to paint the 8-color block */
345 if ((opcode & 0xF0) == 0xC0) {
346 /* fetch the next 8 colors from bytestream and store in next
347 * available entry in the color octet table */
348 for (i = 0; i < COCTET; i++) {
349 pixel = s->buf[stream_ptr++];
350 color_table_index = COCTET * color_octet_index + i;
351 s->color_octets[color_table_index] = pixel;
353 /* this is the base index to use for this block */
354 color_table_index = COCTET * color_octet_index;
357 if (color_octet_index == COLORS_PER_TABLE)
358 color_octet_index = 0;
360 color_table_index = COCTET * s->buf[stream_ptr++];
364 For this input of 6 hex bytes:
366 Mangle it to this output:
367 flags_a = xx012456, flags_b = xx89A37B
369 /* build the color flags */
370 color_flags_a = color_flags_b = 0;
372 (s->buf[stream_ptr + 0] << 16) |
373 ((s->buf[stream_ptr + 1] & 0xF0) << 8) |
374 ((s->buf[stream_ptr + 2] & 0xF0) << 4) |
375 ((s->buf[stream_ptr + 2] & 0x0F) << 4) |
376 ((s->buf[stream_ptr + 3] & 0xF0) >> 4);
378 (s->buf[stream_ptr + 4] << 16) |
379 ((s->buf[stream_ptr + 5] & 0xF0) << 8) |
380 ((s->buf[stream_ptr + 1] & 0x0F) << 8) |
381 ((s->buf[stream_ptr + 3] & 0x0F) << 4) |
382 (s->buf[stream_ptr + 5] & 0x0F);
385 color_flags = color_flags_a;
386 /* flag mask actually acts as a bit shift count here */
388 block_ptr = row_ptr + pixel_ptr;
389 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
390 /* reload flags at third row (iteration pixel_y == 2) */
392 color_flags = color_flags_b;
395 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
396 pixel = color_table_index +
397 ((color_flags >> flag_mask) & 0x07);
399 pixels[block_ptr++] = s->color_octets[pixel];
401 block_ptr += row_inc;
407 /* 16-color block encoding (every pixel is a different color) */
409 n_blocks = (opcode & 0x0F) + 1;
412 block_ptr = row_ptr + pixel_ptr;
413 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
414 for (pixel_x = 0; pixel_x < 4; pixel_x++) {
415 pixels[block_ptr++] = s->buf[stream_ptr++];
417 block_ptr += row_inc;
424 av_log(s->avctx, AV_LOG_INFO, "0xF0 opcode seen in SMC chunk (contact the developers)\n");
430 static av_cold int smc_decode_init(AVCodecContext *avctx)
432 SmcContext *s = avctx->priv_data;
435 avctx->pix_fmt = PIX_FMT_PAL8;
437 s->frame.data[0] = NULL;
442 static int smc_decode_frame(AVCodecContext *avctx,
443 void *data, int *data_size,
446 const uint8_t *buf = avpkt->data;
447 int buf_size = avpkt->size;
448 SmcContext *s = avctx->priv_data;
453 s->frame.reference = 1;
454 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
455 FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
456 if (avctx->reget_buffer(avctx, &s->frame)) {
457 av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
461 smc_decode_stream(s);
463 *data_size = sizeof(AVFrame);
464 *(AVFrame*)data = s->frame;
466 /* always report that the buffer was completely consumed */
470 static av_cold int smc_decode_end(AVCodecContext *avctx)
472 SmcContext *s = avctx->priv_data;
474 if (s->frame.data[0])
475 avctx->release_buffer(avctx, &s->frame);
480 AVCodec smc_decoder = {
490 .long_name = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),