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
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.
35 #include "libavutil/intreadwrite.h"
37 #include "bytestream.h"
44 #define COLORS_PER_TABLE 256
46 typedef struct SmcContext
{
48 AVCodecContext
*avctx
;
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
];
61 #define GET_BLOCK_COUNT() \
62 (opcode & 0x10) ? (1 + bytestream2_get_byte(&s->gb)) : 1 + (opcode & 0x0F);
64 #define ADVANCE_BLOCK() \
67 if (pixel_ptr >= width) \
70 row_ptr += stride * 4; \
73 if (total_blocks < 0 + !!n_blocks) \
75 av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
80 static void smc_decode_stream(SmcContext
*s
)
82 int width
= s
->avctx
->width
;
83 int height
= s
->avctx
->height
;
84 int stride
= s
->frame
->linesize
[0];
87 int buf_size
= bytestream2_size(&s
->gb
);
90 unsigned int color_flags
;
91 unsigned int color_flags_a
;
92 unsigned int color_flags_b
;
93 unsigned int flag_mask
;
95 unsigned char *pixels
= s
->frame
->data
[0];
97 int image_size
= height
* s
->frame
->linesize
[0];
100 int pixel_x
, pixel_y
;
101 int row_inc
= stride
- 4;
104 int prev_block_ptr1
, prev_block_ptr2
;
107 int color_table_index
; /* indexes to color pair, quad, or octet tables */
110 int color_pair_index
= 0;
111 int color_quad_index
= 0;
112 int color_octet_index
= 0;
114 /* make the palette available */
115 memcpy(s
->frame
->data
[1], s
->pal
, AVPALETTE_SIZE
);
117 bytestream2_skip(&s
->gb
, 1);
118 chunk_size
= bytestream2_get_be24(&s
->gb
);
119 if (chunk_size
!= buf_size
)
120 av_log(s
->avctx
, AV_LOG_INFO
, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
121 chunk_size
, buf_size
);
123 chunk_size
= buf_size
;
124 total_blocks
= ((s
->avctx
->width
+ 3) / 4) * ((s
->avctx
->height
+ 3) / 4);
126 /* traverse through the blocks */
127 while (total_blocks
) {
129 /* make sure the row pointer hasn't gone wild */
130 if (row_ptr
>= image_size
) {
131 av_log(s
->avctx
, AV_LOG_INFO
, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
132 row_ptr
, image_size
);
136 opcode
= bytestream2_get_byte(&s
->gb
);
137 switch (opcode
& 0xF0) {
141 n_blocks
= GET_BLOCK_COUNT();
147 /* repeat last block n times */
150 n_blocks
= GET_BLOCK_COUNT();
153 if ((row_ptr
== 0) && (pixel_ptr
== 0)) {
154 av_log(s
->avctx
, AV_LOG_INFO
, "encountered repeat block opcode (%02X) but no blocks rendered yet\n",
159 /* figure out where the previous block started */
162 (row_ptr
- s
->avctx
->width
* 4) + s
->avctx
->width
- 4;
164 prev_block_ptr1
= row_ptr
+ pixel_ptr
- 4;
167 block_ptr
= row_ptr
+ pixel_ptr
;
168 prev_block_ptr
= prev_block_ptr1
;
169 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
170 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
171 pixels
[block_ptr
++] = pixels
[prev_block_ptr
++];
173 block_ptr
+= row_inc
;
174 prev_block_ptr
+= row_inc
;
180 /* repeat previous pair of blocks n times */
183 n_blocks
= GET_BLOCK_COUNT();
187 if ((row_ptr
== 0) && (pixel_ptr
< 2 * 4)) {
188 av_log(s
->avctx
, AV_LOG_INFO
, "encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
193 /* figure out where the previous 2 blocks started */
195 prev_block_ptr1
= (row_ptr
- s
->avctx
->width
* 4) +
196 s
->avctx
->width
- 4 * 2;
197 else if (pixel_ptr
== 4)
198 prev_block_ptr1
= (row_ptr
- s
->avctx
->width
* 4) + row_inc
;
200 prev_block_ptr1
= row_ptr
+ pixel_ptr
- 4 * 2;
203 prev_block_ptr2
= (row_ptr
- s
->avctx
->width
* 4) + row_inc
;
205 prev_block_ptr2
= row_ptr
+ pixel_ptr
- 4;
209 block_ptr
= row_ptr
+ pixel_ptr
;
211 prev_block_ptr
= prev_block_ptr2
;
213 prev_block_ptr
= prev_block_ptr1
;
214 prev_block_flag
= !prev_block_flag
;
216 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
217 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
218 pixels
[block_ptr
++] = pixels
[prev_block_ptr
++];
220 block_ptr
+= row_inc
;
221 prev_block_ptr
+= row_inc
;
227 /* 1-color block encoding */
230 n_blocks
= GET_BLOCK_COUNT();
231 pixel
= bytestream2_get_byte(&s
->gb
);
234 block_ptr
= row_ptr
+ pixel_ptr
;
235 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
236 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
237 pixels
[block_ptr
++] = pixel
;
239 block_ptr
+= row_inc
;
245 /* 2-color block encoding */
248 n_blocks
= (opcode
& 0x0F) + 1;
250 /* figure out which color pair to use to paint the 2-color block */
251 if ((opcode
& 0xF0) == 0x80) {
252 /* fetch the next 2 colors from bytestream and store in next
253 * available entry in the color pair table */
254 for (i
= 0; i
< CPAIR
; i
++) {
255 pixel
= bytestream2_get_byte(&s
->gb
);
256 color_table_index
= CPAIR
* color_pair_index
+ i
;
257 s
->color_pairs
[color_table_index
] = pixel
;
259 /* this is the base index to use for this block */
260 color_table_index
= CPAIR
* color_pair_index
;
263 if (color_pair_index
== COLORS_PER_TABLE
)
264 color_pair_index
= 0;
266 color_table_index
= CPAIR
* bytestream2_get_byte(&s
->gb
);
269 color_flags
= bytestream2_get_be16(&s
->gb
);
271 block_ptr
= row_ptr
+ pixel_ptr
;
272 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
273 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
274 if (color_flags
& flag_mask
)
275 pixel
= color_table_index
+ 1;
277 pixel
= color_table_index
;
279 pixels
[block_ptr
++] = s
->color_pairs
[pixel
];
281 block_ptr
+= row_inc
;
287 /* 4-color block encoding */
290 n_blocks
= (opcode
& 0x0F) + 1;
292 /* figure out which color quad to use to paint the 4-color block */
293 if ((opcode
& 0xF0) == 0xA0) {
294 /* fetch the next 4 colors from bytestream and store in next
295 * available entry in the color quad table */
296 for (i
= 0; i
< CQUAD
; i
++) {
297 pixel
= bytestream2_get_byte(&s
->gb
);
298 color_table_index
= CQUAD
* color_quad_index
+ i
;
299 s
->color_quads
[color_table_index
] = pixel
;
301 /* this is the base index to use for this block */
302 color_table_index
= CQUAD
* color_quad_index
;
305 if (color_quad_index
== COLORS_PER_TABLE
)
306 color_quad_index
= 0;
308 color_table_index
= CQUAD
* bytestream2_get_byte(&s
->gb
);
311 color_flags
= bytestream2_get_be32(&s
->gb
);
312 /* flag mask actually acts as a bit shift count here */
314 block_ptr
= row_ptr
+ pixel_ptr
;
315 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
316 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
317 pixel
= color_table_index
+
318 ((color_flags
>> flag_mask
) & 0x03);
320 pixels
[block_ptr
++] = s
->color_quads
[pixel
];
322 block_ptr
+= row_inc
;
328 /* 8-color block encoding */
331 n_blocks
= (opcode
& 0x0F) + 1;
333 /* figure out which color octet to use to paint the 8-color block */
334 if ((opcode
& 0xF0) == 0xC0) {
335 /* fetch the next 8 colors from bytestream and store in next
336 * available entry in the color octet table */
337 for (i
= 0; i
< COCTET
; i
++) {
338 pixel
= bytestream2_get_byte(&s
->gb
);
339 color_table_index
= COCTET
* color_octet_index
+ i
;
340 s
->color_octets
[color_table_index
] = pixel
;
342 /* this is the base index to use for this block */
343 color_table_index
= COCTET
* color_octet_index
;
346 if (color_octet_index
== COLORS_PER_TABLE
)
347 color_octet_index
= 0;
349 color_table_index
= COCTET
* bytestream2_get_byte(&s
->gb
);
353 For this input of 6 hex bytes:
355 Mangle it to this output:
356 flags_a = xx012456, flags_b = xx89A37B
358 /* build the color flags */
359 int val1
= bytestream2_get_be16(&s
->gb
);
360 int val2
= bytestream2_get_be16(&s
->gb
);
361 int val3
= bytestream2_get_be16(&s
->gb
);
362 color_flags_a
= ((val1
& 0xFFF0) << 8) | (val2
>> 4);
363 color_flags_b
= ((val3
& 0xFFF0) << 8) |
364 ((val1
& 0x0F) << 8) | ((val2
& 0x0F) << 4) | (val3
& 0x0F);
366 color_flags
= color_flags_a
;
367 /* flag mask actually acts as a bit shift count here */
369 block_ptr
= row_ptr
+ pixel_ptr
;
370 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
371 /* reload flags at third row (iteration pixel_y == 2) */
373 color_flags
= color_flags_b
;
376 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
377 pixel
= color_table_index
+
378 ((color_flags
>> flag_mask
) & 0x07);
380 pixels
[block_ptr
++] = s
->color_octets
[pixel
];
382 block_ptr
+= row_inc
;
388 /* 16-color block encoding (every pixel is a different color) */
390 n_blocks
= (opcode
& 0x0F) + 1;
393 block_ptr
= row_ptr
+ pixel_ptr
;
394 for (pixel_y
= 0; pixel_y
< 4; pixel_y
++) {
395 for (pixel_x
= 0; pixel_x
< 4; pixel_x
++) {
396 pixels
[block_ptr
++] = bytestream2_get_byte(&s
->gb
);
398 block_ptr
+= row_inc
;
405 avpriv_request_sample(s
->avctx
, "0xF0 opcode");
413 static av_cold
int smc_decode_init(AVCodecContext
*avctx
)
415 SmcContext
*s
= avctx
->priv_data
;
418 avctx
->pix_fmt
= AV_PIX_FMT_PAL8
;
420 s
->frame
= av_frame_alloc();
422 return AVERROR(ENOMEM
);
427 static int smc_decode_frame(AVCodecContext
*avctx
,
428 void *data
, int *got_frame
,
431 const uint8_t *buf
= avpkt
->data
;
432 int buf_size
= avpkt
->size
;
433 SmcContext
*s
= avctx
->priv_data
;
434 const uint8_t *pal
= av_packet_get_side_data(avpkt
, AV_PKT_DATA_PALETTE
, NULL
);
437 bytestream2_init(&s
->gb
, buf
, buf_size
);
439 if ((ret
= ff_reget_buffer(avctx
, s
->frame
)) < 0)
443 s
->frame
->palette_has_changed
= 1;
444 memcpy(s
->pal
, pal
, AVPALETTE_SIZE
);
447 smc_decode_stream(s
);
450 if ((ret
= av_frame_ref(data
, s
->frame
)) < 0)
453 /* always report that the buffer was completely consumed */
457 static av_cold
int smc_decode_end(AVCodecContext
*avctx
)
459 SmcContext
*s
= avctx
->priv_data
;
461 av_frame_free(&s
->frame
);
466 AVCodec ff_smc_decoder
= {
468 .long_name
= NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
469 .type
= AVMEDIA_TYPE_VIDEO
,
470 .id
= AV_CODEC_ID_SMC
,
471 .priv_data_size
= sizeof(SmcContext
),
472 .init
= smc_decode_init
,
473 .close
= smc_decode_end
,
474 .decode
= smc_decode_frame
,
475 .capabilities
= CODEC_CAP_DR1
,