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 #define BE_16(x) ((((uint8_t*)(x))[0] << 8) | ((uint8_t*)(x))[1])
62 #define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0])
63 #define LE_32(x) ((((uint8_t*)(x))[3] << 24) | \
64 (((uint8_t*)(x))[2] << 16) | \
65 (((uint8_t*)(x))[1] << 8) | \
68 /* RGB -> YUV conversion stuff */
69 #define SCALEFACTOR 65536
70 #define CENTERSAMPLE 128
72 #define COMPUTE_Y(r, g, b) \
74 ((y_r_table[r] + y_g_table[g] + y_b_table[b]) / SCALEFACTOR)
75 #define COMPUTE_U(r, g, b) \
77 ((u_r_table[r] + u_g_table[g] + u_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
78 #define COMPUTE_V(r, g, b) \
80 ((v_r_table[r] + v_g_table[g] + v_b_table[b]) / SCALEFACTOR + CENTERSAMPLE)
82 #define Y_R (SCALEFACTOR * 0.29900)
83 #define Y_G (SCALEFACTOR * 0.58700)
84 #define Y_B (SCALEFACTOR * 0.11400)
86 #define U_R (SCALEFACTOR * -0.16874)
87 #define U_G (SCALEFACTOR * -0.33126)
88 #define U_B (SCALEFACTOR * 0.50000)
90 #define V_R (SCALEFACTOR * 0.50000)
91 #define V_G (SCALEFACTOR * -0.41869)
92 #define V_B (SCALEFACTOR * -0.08131)
95 * Precalculate all of the YUV tables since it requires fewer than
96 * 10 kilobytes to store them.
98 static int y_r_table[256];
99 static int y_g_table[256];
100 static int y_b_table[256];
102 static int u_r_table[256];
103 static int u_g_table[256];
104 static int u_b_table[256];
106 static int v_r_table[256];
107 static int v_g_table[256];
108 static int v_b_table[256];
110 static int xan_decode_init(AVCodecContext *avctx)
112 XanContext *s = avctx->priv_data;
117 if ((avctx->codec->id == CODEC_ID_XAN_WC3) &&
118 (s->avctx->palctrl == NULL)) {
119 av_log(avctx, AV_LOG_ERROR, " WC3 Xan video: palette expected.\n");
123 avctx->pix_fmt = PIX_FMT_PAL8;
124 avctx->has_b_frames = 0;
125 dsputil_init(&s->dsp, avctx);
127 /* initialize the RGB -> YUV tables */
128 for (i = 0; i < 256; i++) {
129 y_r_table[i] = Y_R * i;
130 y_g_table[i] = Y_G * i;
131 y_b_table[i] = Y_B * i;
133 u_r_table[i] = U_R * i;
134 u_g_table[i] = U_G * i;
135 u_b_table[i] = U_B * i;
137 v_r_table[i] = V_R * i;
138 v_g_table[i] = V_G * i;
139 v_b_table[i] = V_B * i;
142 s->buffer1 = av_malloc(avctx->width * avctx->height);
143 s->buffer2 = av_malloc(avctx->width * avctx->height);
144 if (!s->buffer1 || !s->buffer2)
150 /* This function is used in lieu of memcpy(). This decoder can not use
151 * memcpy because the memory locations often overlap and
152 * memcpy doesn't like that; it's not uncommon, for example, for
153 * dest = src+1, to turn byte A into pattern AAAAAAAA.
154 * This was originally repz movsb in Intel x86 ASM. */
155 static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)
159 for (i = 0; i < count; i++)
163 static int xan_huffman_decode(unsigned char *dest, unsigned char *src)
165 unsigned char byte = *src++;
166 unsigned char ival = byte + 0x16;
167 unsigned char * ptr = src + byte*2;
168 unsigned char val = ival;
171 unsigned char bits = *ptr++;
173 while ( val != 0x16 ) {
174 if ( (1 << counter) & bits )
175 val = src[byte + val - 0x17];
177 val = src[val - 0x17];
184 if (counter++ == 7) {
193 static void xan_unpack(unsigned char *dest, unsigned char *src)
195 unsigned char opcode;
198 int byte1, byte2, byte3;
203 if ( (opcode & 0x80) == 0 ) {
208 bytecopy(dest, src, size); dest += size; src += size;
210 size = ((opcode & 0x1c) >> 2) + 3;
211 bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);
214 } else if ( (opcode & 0x40) == 0 ) {
220 bytecopy (dest, src, size); dest += size; src += size;
222 size = (opcode & 0x3f) + 4;
223 bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);
226 } else if ( (opcode & 0x20) == 0 ) {
233 bytecopy (dest, src, size); dest += size; src += size;
235 size = byte3 + 5 + ((opcode & 0xc) << 6);
237 dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),
241 size = ((opcode & 0x1f) << 2) + 4;
246 bytecopy (dest, src, size); dest += size; src += size;
251 bytecopy(dest, src, size); dest += size; src += size;
254 static void inline xan_wc3_build_palette(XanContext *s,
255 unsigned int *palette_data)
258 unsigned char r, g, b;
259 unsigned short *palette16;
260 unsigned int *palette32;
261 unsigned int pal_elem;
263 /* transform the palette passed through the palette control structure
264 * into the necessary internal format depending on colorspace */
266 switch (s->avctx->pix_fmt) {
269 palette16 = (unsigned short *)s->palette;
270 for (i = 0; i < PALETTE_COUNT; i++) {
271 pal_elem = palette_data[i];
272 r = (pal_elem >> 16) & 0xff;
273 g = (pal_elem >> 8) & 0xff;
283 palette16 = (unsigned short *)s->palette;
284 for (i = 0; i < PALETTE_COUNT; i++) {
285 pal_elem = palette_data[i];
286 r = (pal_elem >> 16) & 0xff;
287 g = (pal_elem >> 8) & 0xff;
297 for (i = 0; i < PALETTE_COUNT; i++) {
298 pal_elem = palette_data[i];
299 r = (pal_elem >> 16) & 0xff;
300 g = (pal_elem >> 8) & 0xff;
302 s->palette[i * 4 + 0] = r;
303 s->palette[i * 4 + 1] = g;
304 s->palette[i * 4 + 2] = b;
309 for (i = 0; i < PALETTE_COUNT; i++) {
310 pal_elem = palette_data[i];
311 r = (pal_elem >> 16) & 0xff;
312 g = (pal_elem >> 8) & 0xff;
314 s->palette[i * 4 + 0] = b;
315 s->palette[i * 4 + 1] = g;
316 s->palette[i * 4 + 2] = r;
322 palette32 = (unsigned int *)s->palette;
323 memcpy (palette32, palette_data, PALETTE_COUNT * sizeof(unsigned int));
326 case PIX_FMT_YUV444P:
327 for (i = 0; i < PALETTE_COUNT; i++) {
328 pal_elem = palette_data[i];
329 r = (pal_elem >> 16) & 0xff;
330 g = (pal_elem >> 8) & 0xff;
332 s->palette[i * 4 + 0] = COMPUTE_Y(r, g, b);
333 s->palette[i * 4 + 1] = COMPUTE_U(r, g, b);
334 s->palette[i * 4 + 2] = COMPUTE_V(r, g, b);
339 av_log(s->avctx, AV_LOG_ERROR, " Xan WC3: Unhandled colorspace\n");
344 /* advance current_x variable; reset accounting variables if current_x
345 * moves beyond width */
346 #define ADVANCE_CURRENT_X() \
348 if (current_x >= width) { \
353 static void inline xan_wc3_output_pixel_run(XanContext *s,
354 unsigned char *pixel_buffer, int x, int y, int pixel_count)
360 int width = s->avctx->width;
362 unsigned char *palette_plane;
363 unsigned char *y_plane;
364 unsigned char *u_plane;
365 unsigned char *v_plane;
366 unsigned char *rgb_plane;
367 unsigned short *rgb16_plane;
368 unsigned short *palette16;
369 unsigned int *rgb32_plane;
370 unsigned int *palette32;
372 switch (s->avctx->pix_fmt) {
375 palette_plane = s->current_frame.data[0];
376 stride = s->current_frame.linesize[0];
377 line_inc = stride - width;
378 index = y * stride + x;
380 while(pixel_count--) {
382 /* don't do a memcpy() here; keyframes generally copy an entire
383 * frame of data and the stride needs to be accounted for */
384 palette_plane[index++] = *pixel_buffer++;
392 rgb16_plane = (unsigned short *)s->current_frame.data[0];
393 palette16 = (unsigned short *)s->palette;
394 stride = s->current_frame.linesize[0] / 2;
395 line_inc = stride - width;
396 index = y * stride + x;
398 while(pixel_count--) {
400 rgb16_plane[index++] = palette16[*pixel_buffer++];
408 rgb_plane = s->current_frame.data[0];
409 stride = s->current_frame.linesize[0];
410 line_inc = stride - width * 3;
411 index = y * stride + x * 3;
413 while(pixel_count--) {
414 pix = *pixel_buffer++;
416 rgb_plane[index++] = s->palette[pix * 4 + 0];
417 rgb_plane[index++] = s->palette[pix * 4 + 1];
418 rgb_plane[index++] = s->palette[pix * 4 + 2];
425 rgb32_plane = (unsigned int *)s->current_frame.data[0];
426 palette32 = (unsigned int *)s->palette;
427 stride = s->current_frame.linesize[0] / 4;
428 line_inc = stride - width;
429 index = y * stride + x;
431 while(pixel_count--) {
433 rgb32_plane[index++] = palette32[*pixel_buffer++];
439 case PIX_FMT_YUV444P:
440 y_plane = s->current_frame.data[0];
441 u_plane = s->current_frame.data[1];
442 v_plane = s->current_frame.data[2];
443 stride = s->current_frame.linesize[0];
444 line_inc = stride - width;
445 index = y * stride + x;
447 while(pixel_count--) {
448 pix = *pixel_buffer++;
450 y_plane[index] = s->palette[pix * 4 + 0];
451 u_plane[index] = s->palette[pix * 4 + 1];
452 v_plane[index] = s->palette[pix * 4 + 2];
460 av_log(s->avctx, AV_LOG_ERROR, " Xan WC3: Unhandled colorspace\n");
465 #define ADVANCE_CURFRAME_X() \
467 if (curframe_x >= width) { \
468 curframe_index += line_inc; \
472 #define ADVANCE_PREVFRAME_X() \
474 if (prevframe_x >= width) { \
475 prevframe_index += line_inc; \
479 static void inline xan_wc3_copy_pixel_run(XanContext *s,
480 int x, int y, int pixel_count, int motion_x, int motion_y)
484 int curframe_index, prevframe_index;
485 int curframe_x, prevframe_x;
486 int width = s->avctx->width;
487 unsigned char *palette_plane, *prev_palette_plane;
488 unsigned char *y_plane, *u_plane, *v_plane;
489 unsigned char *prev_y_plane, *prev_u_plane, *prev_v_plane;
490 unsigned char *rgb_plane, *prev_rgb_plane;
491 unsigned short *rgb16_plane, *prev_rgb16_plane;
492 unsigned int *rgb32_plane, *prev_rgb32_plane;
494 switch (s->avctx->pix_fmt) {
497 palette_plane = s->current_frame.data[0];
498 prev_palette_plane = s->last_frame.data[0];
499 stride = s->current_frame.linesize[0];
500 line_inc = stride - width;
501 curframe_index = y * stride + x;
503 prevframe_index = (y + motion_y) * stride + x + motion_x;
504 prevframe_x = x + motion_x;
505 while(pixel_count--) {
507 palette_plane[curframe_index++] =
508 prev_palette_plane[prevframe_index++];
510 ADVANCE_CURFRAME_X();
511 ADVANCE_PREVFRAME_X();
517 rgb16_plane = (unsigned short *)s->current_frame.data[0];
518 prev_rgb16_plane = (unsigned short *)s->last_frame.data[0];
519 stride = s->current_frame.linesize[0] / 2;
520 line_inc = stride - width;
521 curframe_index = y * stride + x;
523 prevframe_index = (y + motion_y) * stride + x + motion_x;
524 prevframe_x = x + motion_x;
525 while(pixel_count--) {
527 rgb16_plane[curframe_index++] =
528 prev_rgb16_plane[prevframe_index++];
530 ADVANCE_CURFRAME_X();
531 ADVANCE_PREVFRAME_X();
537 rgb_plane = s->current_frame.data[0];
538 prev_rgb_plane = s->last_frame.data[0];
539 stride = s->current_frame.linesize[0];
540 line_inc = stride - width * 3;
541 curframe_index = y * stride + x * 3;
543 prevframe_index = (y + motion_y) * stride +
544 (3 * (x + motion_x));
545 prevframe_x = x + motion_x;
546 while(pixel_count--) {
548 rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
549 rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
550 rgb_plane[curframe_index++] = prev_rgb_plane[prevframe_index++];
552 ADVANCE_CURFRAME_X();
553 ADVANCE_PREVFRAME_X();
558 rgb32_plane = (unsigned int *)s->current_frame.data[0];
559 prev_rgb32_plane = (unsigned int *)s->last_frame.data[0];
560 stride = s->current_frame.linesize[0] / 4;
561 line_inc = stride - width;
562 curframe_index = y * stride + x;
564 prevframe_index = (y + motion_y) * stride + x + motion_x;
565 prevframe_x = x + motion_x;
566 while(pixel_count--) {
568 rgb32_plane[curframe_index++] =
569 prev_rgb32_plane[prevframe_index++];
571 ADVANCE_CURFRAME_X();
572 ADVANCE_PREVFRAME_X();
576 case PIX_FMT_YUV444P:
577 y_plane = s->current_frame.data[0];
578 u_plane = s->current_frame.data[1];
579 v_plane = s->current_frame.data[2];
580 prev_y_plane = s->last_frame.data[0];
581 prev_u_plane = s->last_frame.data[1];
582 prev_v_plane = s->last_frame.data[2];
583 stride = s->current_frame.linesize[0];
584 line_inc = stride - width;
585 curframe_index = y * stride + x;
587 prevframe_index = (y + motion_y) * stride + x + motion_x;
588 prevframe_x = x + motion_x;
589 while(pixel_count--) {
591 y_plane[curframe_index] = prev_y_plane[prevframe_index];
592 u_plane[curframe_index] = prev_u_plane[prevframe_index];
593 v_plane[curframe_index] = prev_v_plane[prevframe_index];
596 ADVANCE_CURFRAME_X();
598 ADVANCE_PREVFRAME_X();
603 av_log(s->avctx, AV_LOG_ERROR, " Xan WC3: Unhandled colorspace\n");
608 static void xan_wc3_decode_frame(XanContext *s) {
610 int width = s->avctx->width;
611 int height = s->avctx->height;
612 int total_pixels = width * height;
613 unsigned char opcode;
614 unsigned char flag = 0;
616 int motion_x, motion_y;
619 unsigned char *opcode_buffer = s->buffer1;
620 unsigned char *imagedata_buffer = s->buffer2;
622 /* pointers to segments inside the compressed chunk */
623 unsigned char *huffman_segment;
624 unsigned char *size_segment;
625 unsigned char *vector_segment;
626 unsigned char *imagedata_segment;
628 huffman_segment = s->buf + LE_16(&s->buf[0]);
629 size_segment = s->buf + LE_16(&s->buf[2]);
630 vector_segment = s->buf + LE_16(&s->buf[4]);
631 imagedata_segment = s->buf + LE_16(&s->buf[6]);
633 xan_huffman_decode(opcode_buffer, huffman_segment);
635 if (imagedata_segment[0] == 2)
636 xan_unpack(imagedata_buffer, &imagedata_segment[1]);
638 imagedata_buffer = &imagedata_segment[1];
640 /* use the decoded data segments to build the frame */
642 while (total_pixels) {
644 opcode = *opcode_buffer++;
671 size += (opcode - 10);
676 size = *size_segment++;
681 size = BE_16(&size_segment[0]);
687 size = (size_segment[0] << 16) | (size_segment[1] << 8) |
696 /* run of (size) pixels is unchanged from last frame */
697 xan_wc3_copy_pixel_run(s, x, y, size, 0, 0);
699 /* output a run of pixels from imagedata_buffer */
700 xan_wc3_output_pixel_run(s, imagedata_buffer, x, y, size);
701 imagedata_buffer += size;
704 /* run-based motion compensation from last frame */
705 motion_x = (*vector_segment >> 4) & 0xF;
706 motion_y = *vector_segment & 0xF;
711 motion_x |= 0xFFFFFFF0;
713 motion_y |= 0xFFFFFFF0;
715 /* copy a run of pixels from the previous frame */
716 xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);
721 /* coordinate accounting */
722 total_pixels -= size;
724 if (x + size >= width) {
735 /* for PAL8, make the palette available on the way out */
736 if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
737 memcpy(s->current_frame.data[1], s->palette, PALETTE_COUNT * 4);
738 s->current_frame.palette_has_changed = 1;
739 s->avctx->palctrl->palette_changed = 0;
743 static void xan_wc4_decode_frame(XanContext *s) {
746 static int xan_decode_frame(AVCodecContext *avctx,
747 void *data, int *data_size,
748 uint8_t *buf, int buf_size)
750 XanContext *s = avctx->priv_data;
751 AVPaletteControl *palette_control = avctx->palctrl;
754 if (palette_control->palette_changed) {
755 /* load the new palette and reset the palette control */
756 xan_wc3_build_palette(s, palette_control->palette);
757 /* If pal8 we clear flag when we copy palette */
758 if (s->avctx->pix_fmt != PIX_FMT_PAL8)
759 palette_control->palette_changed = 0;
763 if (avctx->get_buffer(avctx, &s->current_frame)) {
764 av_log(s->avctx, AV_LOG_ERROR, " Xan Video: get_buffer() failed\n");
767 s->current_frame.reference = 3;
772 if (avctx->codec->id == CODEC_ID_XAN_WC3)
773 xan_wc3_decode_frame(s);
774 else if (avctx->codec->id == CODEC_ID_XAN_WC4)
775 xan_wc4_decode_frame(s);
777 /* release the last frame if it is allocated */
778 if (s->last_frame.data[0])
779 avctx->release_buffer(avctx, &s->last_frame);
782 s->last_frame = s->current_frame;
784 *data_size = sizeof(AVFrame);
785 *(AVFrame*)data = s->current_frame;
787 /* always report that the buffer was completely consumed */
791 static int xan_decode_end(AVCodecContext *avctx)
793 XanContext *s = avctx->priv_data;
795 /* release the last frame */
796 avctx->release_buffer(avctx, &s->last_frame);
804 AVCodec xan_wc3_decoder = {
817 AVCodec xan_wc4_decoder = {