2 * Wing Commander/Xan Video Decoder
3 * Copyright (C) 2003 the ffmpeg project
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 * Xan video decoder for Wing Commander III & IV computer games
24 * by Mario Brito (mbrito@student.dei.uc.pt)
25 * and Mike Melanson (melanson@pcisys.net)
27 * The xan_wc3 decoder outputs the following colorspaces natively:
28 * PAL8 (default), RGB555, RGB565, RGB24, BGR24, RGBA32, YUV444P
40 #define PALETTE_COUNT 256
41 #define PALETTE_CONTROL_SIZE ((256 * 3) + 1)
43 typedef struct XanContext {
45 AVCodecContext *avctx;
48 AVFrame current_frame;
53 unsigned char palette[PALETTE_COUNT * 4];
56 unsigned char *buffer1;
57 unsigned char *buffer2;
61 /* RGB -> YUV conversion stuff */
62 #define SCALEFACTOR 65536
63 #define CENTERSAMPLE 128
65 #define COMPUTE_Y(r, g, b) \
67 ((y_r_table[r] + y_g_table[g] + y_b_table[b]) / SCALEFACTOR)
68 #define COMPUTE_U(r, g, b) \
70 ((u_r_table[r] + u_g_table[g] + u_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
71 #define COMPUTE_V(r, g, b) \
73 ((v_r_table[r] + v_g_table[g] + v_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
75 #define Y_R (SCALEFACTOR * 0.29900)
76 #define Y_G (SCALEFACTOR * 0.58700)
77 #define Y_B (SCALEFACTOR * 0.11400)
79 #define U_R (SCALEFACTOR * -0.16874)
80 #define U_G (SCALEFACTOR * -0.33126)
81 #define U_B (SCALEFACTOR * 0.50000)
83 #define V_R (SCALEFACTOR * 0.50000)
84 #define V_G (SCALEFACTOR * -0.41869)
85 #define V_B (SCALEFACTOR * -0.08131)
88 * Precalculate all of the YUV tables since it requires fewer than
89 * 10 kilobytes to store them.
91 static int y_r_table[256];
92 static int y_g_table[256];
93 static int y_b_table[256];
95 static int u_r_table[256];
96 static int u_g_table[256];
97 static int u_b_table[256];
99 static int v_r_table[256];
100 static int v_g_table[256];
101 static int v_b_table[256];
103 static int xan_decode_init(AVCodecContext *avctx)
105 XanContext *s = avctx->priv_data;
110 if ((avctx->codec->id == CODEC_ID_XAN_WC3) &&
111 (s->avctx->palctrl == NULL)) {
112 av_log(avctx, AV_LOG_ERROR, " WC3 Xan video: palette expected.\n");
116 avctx->pix_fmt = PIX_FMT_PAL8;
117 avctx->has_b_frames = 0;
118 dsputil_init(&s->dsp, avctx);
120 /* initialize the RGB -> YUV tables */
121 for (i = 0; i < 256; i++) {
122 y_r_table[i] = Y_R * i;
123 y_g_table[i] = Y_G * i;
124 y_b_table[i] = Y_B * i;
126 u_r_table[i] = U_R * i;
127 u_g_table[i] = U_G * i;
128 u_b_table[i] = U_B * i;
130 v_r_table[i] = V_R * i;
131 v_g_table[i] = V_G * i;
132 v_b_table[i] = V_B * i;
135 if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
138 s->buffer1 = av_malloc(avctx->width * avctx->height);
139 s->buffer2 = av_malloc(avctx->width * avctx->height);
140 if (!s->buffer1 || !s->buffer2)
146 /* This function is used in lieu of memcpy(). This decoder can not use
147 * memcpy because the memory locations often overlap and
148 * memcpy doesn't like that; it's not uncommon, for example, for
149 * dest = src+1, to turn byte A into pattern AAAAAAAA.
150 * This was originally repz movsb in Intel x86 ASM. */
151 static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)
155 for (i = 0; i < count; i++)
159 static int xan_huffman_decode(unsigned char *dest, unsigned char *src)
161 unsigned char byte = *src++;
162 unsigned char ival = byte + 0x16;
163 unsigned char * ptr = src + byte*2;
164 unsigned char val = ival;
167 unsigned char bits = *ptr++;
169 while ( val != 0x16 ) {
170 if ( (1 << counter) & bits )
171 val = src[byte + val - 0x17];
173 val = src[val - 0x17];
180 if (counter++ == 7) {
189 static void xan_unpack(unsigned char *dest, unsigned char *src)
191 unsigned char opcode;
194 int byte1, byte2, byte3;
199 if ( (opcode & 0x80) == 0 ) {
204 bytecopy(dest, src, size); dest += size; src += size;
206 size = ((opcode & 0x1c) >> 2) + 3;
207 bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);
210 } else if ( (opcode & 0x40) == 0 ) {
216 bytecopy (dest, src, size); dest += size; src += size;
218 size = (opcode & 0x3f) + 4;
219 bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);
222 } else if ( (opcode & 0x20) == 0 ) {
229 bytecopy (dest, src, size); dest += size; src += size;
231 size = byte3 + 5 + ((opcode & 0xc) << 6);
233 dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),
237 size = ((opcode & 0x1f) << 2) + 4;
242 bytecopy (dest, src, size); dest += size; src += size;
247 bytecopy(dest, src, size); dest += size; src += size;
250 static void inline xan_wc3_build_palette(XanContext *s,
251 unsigned int *palette_data)
254 unsigned char r, g, b;
255 unsigned short *palette16;
256 unsigned int *palette32;
257 unsigned int pal_elem;
259 /* transform the palette passed through the palette control structure
260 * into the necessary internal format depending on colorspace */
262 switch (s->avctx->pix_fmt) {
265 palette16 = (unsigned short *)s->palette;
266 for (i = 0; i < PALETTE_COUNT; i++) {
267 pal_elem = palette_data[i];
268 r = (pal_elem >> 16) & 0xff;
269 g = (pal_elem >> 8) & 0xff;
279 palette16 = (unsigned short *)s->palette;
280 for (i = 0; i < PALETTE_COUNT; i++) {
281 pal_elem = palette_data[i];
282 r = (pal_elem >> 16) & 0xff;
283 g = (pal_elem >> 8) & 0xff;
293 for (i = 0; i < PALETTE_COUNT; i++) {
294 pal_elem = palette_data[i];
295 r = (pal_elem >> 16) & 0xff;
296 g = (pal_elem >> 8) & 0xff;
298 s->palette[i * 4 + 0] = r;
299 s->palette[i * 4 + 1] = g;
300 s->palette[i * 4 + 2] = b;
305 for (i = 0; i < PALETTE_COUNT; i++) {
306 pal_elem = palette_data[i];
307 r = (pal_elem >> 16) & 0xff;
308 g = (pal_elem >> 8) & 0xff;
310 s->palette[i * 4 + 0] = b;
311 s->palette[i * 4 + 1] = g;
312 s->palette[i * 4 + 2] = r;
318 palette32 = (unsigned int *)s->palette;
319 memcpy (palette32, palette_data, PALETTE_COUNT * sizeof(unsigned int));
322 case PIX_FMT_YUV444P:
323 for (i = 0; i < PALETTE_COUNT; i++) {
324 pal_elem = palette_data[i];
325 r = (pal_elem >> 16) & 0xff;
326 g = (pal_elem >> 8) & 0xff;
328 s->palette[i * 4 + 0] = COMPUTE_Y(r, g, b);
329 s->palette[i * 4 + 1] = COMPUTE_U(r, g, b);
330 s->palette[i * 4 + 2] = COMPUTE_V(r, g, b);
335 av_log(s->avctx, AV_LOG_ERROR, " Xan WC3: Unhandled colorspace\n");
340 /* advance current_x variable; reset accounting variables if current_x
341 * moves beyond width */
342 #define ADVANCE_CURRENT_X() \
344 if (current_x >= width) { \
349 static void inline xan_wc3_output_pixel_run(XanContext *s,
350 unsigned char *pixel_buffer, int x, int y, int pixel_count)
356 int width = s->avctx->width;
358 unsigned char *palette_plane;
359 unsigned char *y_plane;
360 unsigned char *u_plane;
361 unsigned char *v_plane;
362 unsigned char *rgb_plane;
363 unsigned short *rgb16_plane;
364 unsigned short *palette16;
365 unsigned int *rgb32_plane;
366 unsigned int *palette32;
368 switch (s->avctx->pix_fmt) {
371 palette_plane = s->current_frame.data[0];
372 stride = s->current_frame.linesize[0];
373 line_inc = stride - width;
374 index = y * stride + x;
376 while(pixel_count--) {
378 /* don't do a memcpy() here; keyframes generally copy an entire
379 * frame of data and the stride needs to be accounted for */
380 palette_plane[index++] = *pixel_buffer++;
388 rgb16_plane = (unsigned short *)s->current_frame.data[0];
389 palette16 = (unsigned short *)s->palette;
390 stride = s->current_frame.linesize[0] / 2;
391 line_inc = stride - width;
392 index = y * stride + x;
394 while(pixel_count--) {
396 rgb16_plane[index++] = palette16[*pixel_buffer++];
404 rgb_plane = s->current_frame.data[0];
405 stride = s->current_frame.linesize[0];
406 line_inc = stride - width * 3;
407 index = y * stride + x * 3;
409 while(pixel_count--) {
410 pix = *pixel_buffer++;
412 rgb_plane[index++] = s->palette[pix * 4 + 0];
413 rgb_plane[index++] = s->palette[pix * 4 + 1];
414 rgb_plane[index++] = s->palette[pix * 4 + 2];
421 rgb32_plane = (unsigned int *)s->current_frame.data[0];
422 palette32 = (unsigned int *)s->palette;
423 stride = s->current_frame.linesize[0] / 4;
424 line_inc = stride - width;
425 index = y * stride + x;
427 while(pixel_count--) {
429 rgb32_plane[index++] = palette32[*pixel_buffer++];
435 case PIX_FMT_YUV444P:
436 y_plane = s->current_frame.data[0];
437 u_plane = s->current_frame.data[1];
438 v_plane = s->current_frame.data[2];
439 stride = s->current_frame.linesize[0];
440 line_inc = stride - width;
441 index = y * stride + x;
443 while(pixel_count--) {
444 pix = *pixel_buffer++;
446 y_plane[index] = s->palette[pix * 4 + 0];
447 u_plane[index] = s->palette[pix * 4 + 1];
448 v_plane[index] = s->palette[pix * 4 + 2];
456 av_log(s->avctx, AV_LOG_ERROR, " Xan WC3: Unhandled colorspace\n");
461 #define ADVANCE_CURFRAME_X() \
463 if (curframe_x >= width) { \
464 curframe_index += line_inc; \
468 #define ADVANCE_PREVFRAME_X() \
470 if (prevframe_x >= width) { \
471 prevframe_index += line_inc; \
475 static void inline xan_wc3_copy_pixel_run(XanContext *s,
476 int x, int y, int pixel_count, int motion_x, int motion_y)
480 int curframe_index, prevframe_index;
481 int curframe_x, prevframe_x;
482 int width = s->avctx->width;
483 unsigned char *palette_plane, *prev_palette_plane;
484 unsigned char *y_plane, *u_plane, *v_plane;
485 unsigned char *prev_y_plane, *prev_u_plane, *prev_v_plane;
486 unsigned char *rgb_plane, *prev_rgb_plane;
487 unsigned short *rgb16_plane, *prev_rgb16_plane;
488 unsigned int *rgb32_plane, *prev_rgb32_plane;
490 switch (s->avctx->pix_fmt) {
493 palette_plane = s->current_frame.data[0];
494 prev_palette_plane = s->last_frame.data[0];
495 stride = s->current_frame.linesize[0];
496 line_inc = stride - width;
497 curframe_index = y * stride + x;
499 prevframe_index = (y + motion_y) * stride + x + motion_x;
500 prevframe_x = x + motion_x;
501 while(pixel_count--) {
503 palette_plane[curframe_index++] =
504 prev_palette_plane[prevframe_index++];
506 ADVANCE_CURFRAME_X();
507 ADVANCE_PREVFRAME_X();
513 rgb16_plane = (unsigned short *)s->current_frame.data[0];
514 prev_rgb16_plane = (unsigned short *)s->last_frame.data[0];
515 stride = s->current_frame.linesize[0] / 2;
516 line_inc = stride - width;
517 curframe_index = y * stride + x;
519 prevframe_index = (y + motion_y) * stride + x + motion_x;
520 prevframe_x = x + motion_x;
521 while(pixel_count--) {
523 rgb16_plane[curframe_index++] =
524 prev_rgb16_plane[prevframe_index++];
526 ADVANCE_CURFRAME_X();
527 ADVANCE_PREVFRAME_X();
533 rgb_plane = s->current_frame.data[0];
534 prev_rgb_plane = s->last_frame.data[0];
535 stride = s->current_frame.linesize[0];
536 line_inc = stride - width * 3;
537 curframe_index = y * stride + x * 3;
539 prevframe_index = (y + motion_y) * stride +
540 (3 * (x + motion_x));
541 prevframe_x = x + motion_x;
542 while(pixel_count--) {
544 rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
545 rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
546 rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
548 ADVANCE_CURFRAME_X();
549 ADVANCE_PREVFRAME_X();
554 rgb32_plane = (unsigned int *)s->current_frame.data[0];
555 prev_rgb32_plane = (unsigned int *)s->last_frame.data[0];
556 stride = s->current_frame.linesize[0] / 4;
557 line_inc = stride - width;
558 curframe_index = y * stride + x;
560 prevframe_index = (y + motion_y) * stride + x + motion_x;
561 prevframe_x = x + motion_x;
562 while(pixel_count--) {
564 rgb32_plane[curframe_index++] =
565 prev_rgb32_plane[prevframe_index++];
567 ADVANCE_CURFRAME_X();
568 ADVANCE_PREVFRAME_X();
572 case PIX_FMT_YUV444P:
573 y_plane = s->current_frame.data[0];
574 u_plane = s->current_frame.data[1];
575 v_plane = s->current_frame.data[2];
576 prev_y_plane = s->last_frame.data[0];
577 prev_u_plane = s->last_frame.data[1];
578 prev_v_plane = s->last_frame.data[2];
579 stride = s->current_frame.linesize[0];
580 line_inc = stride - width;
581 curframe_index = y * stride + x;
583 prevframe_index = (y + motion_y) * stride + x + motion_x;
584 prevframe_x = x + motion_x;
585 while(pixel_count--) {
587 y_plane[curframe_index] = prev_y_plane[prevframe_index];
588 u_plane[curframe_index] = prev_u_plane[prevframe_index];
589 v_plane[curframe_index] = prev_v_plane[prevframe_index];
592 ADVANCE_CURFRAME_X();
594 ADVANCE_PREVFRAME_X();
599 av_log(s->avctx, AV_LOG_ERROR, " Xan WC3: Unhandled colorspace\n");
604 static void xan_wc3_decode_frame(XanContext *s) {
606 int width = s->avctx->width;
607 int height = s->avctx->height;
608 int total_pixels = width * height;
609 unsigned char opcode;
610 unsigned char flag = 0;
612 int motion_x, motion_y;
615 unsigned char *opcode_buffer = s->buffer1;
616 unsigned char *imagedata_buffer = s->buffer2;
618 /* pointers to segments inside the compressed chunk */
619 unsigned char *huffman_segment;
620 unsigned char *size_segment;
621 unsigned char *vector_segment;
622 unsigned char *imagedata_segment;
624 huffman_segment = s->buf + LE_16(&s->buf[0]);
625 size_segment = s->buf + LE_16(&s->buf[2]);
626 vector_segment = s->buf + LE_16(&s->buf[4]);
627 imagedata_segment = s->buf + LE_16(&s->buf[6]);
629 xan_huffman_decode(opcode_buffer, huffman_segment);
631 if (imagedata_segment[0] == 2)
632 xan_unpack(imagedata_buffer, &imagedata_segment[1]);
634 imagedata_buffer = &imagedata_segment[1];
636 /* use the decoded data segments to build the frame */
638 while (total_pixels) {
640 opcode = *opcode_buffer++;
667 size += (opcode - 10);
672 size = *size_segment++;
677 size = BE_16(&size_segment[0]);
683 size = (size_segment[0] << 16) | (size_segment[1] << 8) |
692 /* run of (size) pixels is unchanged from last frame */
693 xan_wc3_copy_pixel_run(s, x, y, size, 0, 0);
695 /* output a run of pixels from imagedata_buffer */
696 xan_wc3_output_pixel_run(s, imagedata_buffer, x, y, size);
697 imagedata_buffer += size;
700 /* run-based motion compensation from last frame */
701 motion_x = (*vector_segment >> 4) & 0xF;
702 motion_y = *vector_segment & 0xF;
707 motion_x |= 0xFFFFFFF0;
709 motion_y |= 0xFFFFFFF0;
711 /* copy a run of pixels from the previous frame */
712 xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);
717 /* coordinate accounting */
718 total_pixels -= size;
720 if (x + size >= width) {
731 /* for PAL8, make the palette available on the way out */
732 if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
733 memcpy(s->current_frame.data[1], s->palette, PALETTE_COUNT * 4);
734 s->current_frame.palette_has_changed = 1;
735 s->avctx->palctrl->palette_changed = 0;
739 static void xan_wc4_decode_frame(XanContext *s) {
742 static int xan_decode_frame(AVCodecContext *avctx,
743 void *data, int *data_size,
744 uint8_t *buf, int buf_size)
746 XanContext *s = avctx->priv_data;
747 AVPaletteControl *palette_control = avctx->palctrl;
750 if (palette_control->palette_changed) {
751 /* load the new palette and reset the palette control */
752 xan_wc3_build_palette(s, palette_control->palette);
753 /* If pal8 we clear flag when we copy palette */
754 if (s->avctx->pix_fmt != PIX_FMT_PAL8)
755 palette_control->palette_changed = 0;
759 if (avctx->get_buffer(avctx, &s->current_frame)) {
760 av_log(s->avctx, AV_LOG_ERROR, " Xan Video: get_buffer() failed\n");
763 s->current_frame.reference = 3;
768 if (avctx->codec->id == CODEC_ID_XAN_WC3)
769 xan_wc3_decode_frame(s);
770 else if (avctx->codec->id == CODEC_ID_XAN_WC4)
771 xan_wc4_decode_frame(s);
773 /* release the last frame if it is allocated */
774 if (s->last_frame.data[0])
775 avctx->release_buffer(avctx, &s->last_frame);
778 s->last_frame = s->current_frame;
780 *data_size = sizeof(AVFrame);
781 *(AVFrame*)data = s->current_frame;
783 /* always report that the buffer was completely consumed */
787 static int xan_decode_end(AVCodecContext *avctx)
789 XanContext *s = avctx->priv_data;
791 /* release the last frame */
792 avctx->release_buffer(avctx, &s->last_frame);
800 AVCodec xan_wc3_decoder = {
813 AVCodec xan_wc4_decoder = {