2 * Westwood Studios VQA 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
25 * VQA Video Decoder by Mike Melanson (melanson@pcisys.net)
26 * For more information about the VQA format, visit:
27 * http://wiki.multimedia.cx/index.php?title=VQA
29 * The VQA video decoder outputs PAL8 or RGB555 colorspace data, depending
30 * on the type of data in the file.
32 * This decoder needs the 42-byte VQHD header from the beginning
33 * of the VQA file passed through the extradata field. The VQHD header
36 * bytes 0-3 chunk fourcc: 'VQHD'
37 * bytes 4-7 chunk size in big-endian format, should be 0x0000002A
38 * bytes 8-49 VQHD chunk data
40 * Bytes 8-49 are what this decoder expects to see.
42 * Briefly, VQA is a vector quantized animation format that operates in a
43 * VGA palettized colorspace. It operates on pixel vectors (blocks)
44 * of either 4x2 or 4x4 in size. Compressed VQA chunks can contain vector
45 * codebooks, palette information, and code maps for rendering vectors onto
46 * frames. Any of these components can also be compressed with a run-length
47 * encoding (RLE) algorithm commonly referred to as "format80".
49 * VQA takes a novel approach to rate control. Each group of n frames
50 * (usually, n = 8) relies on a different vector codebook. Rather than
51 * transporting an entire codebook every 8th frame, the new codebook is
52 * broken up into 8 pieces and sent along with the compressed video chunks
53 * for each of the 8 frames preceding the 8 frames which require the
54 * codebook. A full codebook is also sent on the very first frame of a
55 * file. This is an interesting technique, although it makes random file
56 * seeking difficult despite the fact that the frames are all intracoded.
58 * V1,2 VQA uses 12-bit codebook indices. If the 12-bit indices were
59 * packed into bytes and then RLE compressed, bytewise, the results would
60 * be poor. That is why the coding method divides each index into 2 parts,
61 * the top 4 bits and the bottom 8 bits, then RL encodes the 4-bit pieces
62 * together and the 8-bit pieces together. If most of the vectors are
63 * clustered into one group of 256 vectors, most of the 4-bit index pieces
75 #define PALETTE_COUNT 256
76 #define VQA_HEADER_SIZE 0x2A
77 #define CHUNK_PREAMBLE_SIZE 8
79 /* allocate the maximum vector space, regardless of the file version:
80 * (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
81 #define MAX_CODEBOOK_VECTORS 0xFF00
82 #define SOLID_PIXEL_VECTORS 0x100
83 #define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
84 #define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)
86 #define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
87 #define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
88 #define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
89 #define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
90 #define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
91 #define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
92 #define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')
97 #define vqa_debug printf
99 static inline void vqa_debug(const char *format, ...) { }
102 typedef struct VqaContext {
104 AVCodecContext *avctx;
111 uint32_t palette[PALETTE_COUNT];
113 int width; /* width of a frame */
114 int height; /* height of a frame */
115 int vector_width; /* width of individual vector */
116 int vector_height; /* height of individual vector */
117 int vqa_version; /* this should be either 1, 2 or 3 */
119 unsigned char *codebook; /* the current codebook */
121 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
122 int next_codebook_buffer_index;
124 unsigned char *decode_buffer;
125 int decode_buffer_size;
127 /* number of frames to go before replacing codebook */
128 int partial_countdown;
133 static int vqa_decode_init(AVCodecContext *avctx)
135 VqaContext *s = avctx->priv_data;
136 unsigned char *vqa_header;
137 int i, j, codebook_index;;
140 avctx->pix_fmt = PIX_FMT_PAL8;
141 dsputil_init(&s->dsp, avctx);
143 /* make sure the extradata made it */
144 if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
145 av_log(s->avctx, AV_LOG_ERROR, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);
149 /* load up the VQA parameters from the header */
150 vqa_header = (unsigned char *)s->avctx->extradata;
151 s->vqa_version = vqa_header[0];
152 s->width = AV_RL16(&vqa_header[6]);
153 s->height = AV_RL16(&vqa_header[8]);
154 if(avcodec_check_dimensions(avctx, s->width, s->height)){
155 s->width= s->height= 0;
158 s->vector_width = vqa_header[10];
159 s->vector_height = vqa_header[11];
160 s->partial_count = s->partial_countdown = vqa_header[13];
162 /* the vector dimensions have to meet very stringent requirements */
163 if ((s->vector_width != 4) ||
164 ((s->vector_height != 2) && (s->vector_height != 4))) {
165 /* return without further initialization */
169 /* allocate codebooks */
170 s->codebook_size = MAX_CODEBOOK_SIZE;
171 s->codebook = av_malloc(s->codebook_size);
172 s->next_codebook_buffer = av_malloc(s->codebook_size);
174 /* initialize the solid-color vectors */
175 if (s->vector_height == 4) {
176 codebook_index = 0xFF00 * 16;
177 for (i = 0; i < 256; i++)
178 for (j = 0; j < 16; j++)
179 s->codebook[codebook_index++] = i;
181 codebook_index = 0xF00 * 8;
182 for (i = 0; i < 256; i++)
183 for (j = 0; j < 8; j++)
184 s->codebook[codebook_index++] = i;
186 s->next_codebook_buffer_index = 0;
188 /* allocate decode buffer */
189 s->decode_buffer_size = (s->width / s->vector_width) *
190 (s->height / s->vector_height) * 2;
191 s->decode_buffer = av_malloc(s->decode_buffer_size);
193 s->frame.data[0] = NULL;
198 #define CHECK_COUNT() \
199 if (dest_index + count > dest_size) { \
200 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
201 av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
202 dest_index, count, dest_size); \
206 static void decode_format80(unsigned char *src, int src_size,
207 unsigned char *dest, int dest_size, int check_size) {
216 while (src_index < src_size) {
218 vqa_debug(" opcode %02X: ", src[src_index]);
220 /* 0x80 means that frame is finished */
221 if (src[src_index] == 0x80)
224 if (dest_index >= dest_size) {
225 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
226 dest_index, dest_size);
230 if (src[src_index] == 0xFF) {
233 count = AV_RL16(&src[src_index]);
235 src_pos = AV_RL16(&src[src_index]);
237 vqa_debug("(1) copy %X bytes from absolute pos %X\n", count, src_pos);
239 for (i = 0; i < count; i++)
240 dest[dest_index + i] = dest[src_pos + i];
243 } else if (src[src_index] == 0xFE) {
246 count = AV_RL16(&src[src_index]);
248 color = src[src_index++];
249 vqa_debug("(2) set %X bytes to %02X\n", count, color);
251 memset(&dest[dest_index], color, count);
254 } else if ((src[src_index] & 0xC0) == 0xC0) {
256 count = (src[src_index++] & 0x3F) + 3;
257 src_pos = AV_RL16(&src[src_index]);
259 vqa_debug("(3) copy %X bytes from absolute pos %X\n", count, src_pos);
261 for (i = 0; i < count; i++)
262 dest[dest_index + i] = dest[src_pos + i];
265 } else if (src[src_index] > 0x80) {
267 count = src[src_index++] & 0x3F;
268 vqa_debug("(4) copy %X bytes from source to dest\n", count);
270 memcpy(&dest[dest_index], &src[src_index], count);
276 count = ((src[src_index] & 0x70) >> 4) + 3;
277 src_pos = AV_RB16(&src[src_index]) & 0x0FFF;
279 vqa_debug("(5) copy %X bytes from relpos %X\n", count, src_pos);
281 for (i = 0; i < count; i++)
282 dest[dest_index + i] = dest[dest_index - src_pos + i];
287 /* validate that the entire destination buffer was filled; this is
288 * important for decoding frame maps since each vector needs to have a
289 * codebook entry; it is not important for compressed codebooks because
290 * not every entry needs to be filled */
292 if (dest_index < dest_size)
293 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
294 dest_index, dest_size);
297 static void vqa_decode_chunk(VqaContext *s)
299 unsigned int chunk_type;
300 unsigned int chunk_size;
302 unsigned int index = 0;
304 unsigned char r, g, b;
318 int vector_index = 0;
322 int hibytes = s->decode_buffer_size / 2;
324 /* first, traverse through the frame and find the subchunks */
325 while (index < s->size) {
327 chunk_type = AV_RB32(&s->buf[index]);
328 chunk_size = AV_RB32(&s->buf[index + 4]);
330 switch (chunk_type) {
361 av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
362 (chunk_type >> 24) & 0xFF,
363 (chunk_type >> 16) & 0xFF,
364 (chunk_type >> 8) & 0xFF,
365 (chunk_type >> 0) & 0xFF,
370 byte_skip = chunk_size & 0x01;
371 index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
374 /* next, deal with the palette */
375 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
377 /* a chunk should not have both chunk types */
378 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
382 /* decompress the palette chunk */
383 if (cplz_chunk != -1) {
385 /* yet to be handled */
389 /* convert the RGB palette into the machine's endian format */
390 if (cpl0_chunk != -1) {
392 chunk_size = AV_RB32(&s->buf[cpl0_chunk + 4]);
393 /* sanity check the palette size */
394 if (chunk_size / 3 > 256) {
395 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
399 cpl0_chunk += CHUNK_PREAMBLE_SIZE;
400 for (i = 0; i < chunk_size / 3; i++) {
401 /* scale by 4 to transform 6-bit palette -> 8-bit */
402 r = s->buf[cpl0_chunk++] * 4;
403 g = s->buf[cpl0_chunk++] * 4;
404 b = s->buf[cpl0_chunk++] * 4;
405 s->palette[i] = (r << 16) | (g << 8) | (b);
409 /* next, look for a full codebook */
410 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
412 /* a chunk should not have both chunk types */
413 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
417 /* decompress the full codebook chunk */
418 if (cbfz_chunk != -1) {
420 chunk_size = AV_RB32(&s->buf[cbfz_chunk + 4]);
421 cbfz_chunk += CHUNK_PREAMBLE_SIZE;
422 decode_format80(&s->buf[cbfz_chunk], chunk_size,
423 s->codebook, s->codebook_size, 0);
426 /* copy a full codebook */
427 if (cbf0_chunk != -1) {
429 chunk_size = AV_RB32(&s->buf[cbf0_chunk + 4]);
430 /* sanity check the full codebook size */
431 if (chunk_size > MAX_CODEBOOK_SIZE) {
432 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
436 cbf0_chunk += CHUNK_PREAMBLE_SIZE;
438 memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
441 /* decode the frame */
442 if (vptz_chunk == -1) {
444 /* something is wrong if there is no VPTZ chunk */
445 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
449 chunk_size = AV_RB32(&s->buf[vptz_chunk + 4]);
450 vptz_chunk += CHUNK_PREAMBLE_SIZE;
451 decode_format80(&s->buf[vptz_chunk], chunk_size,
452 s->decode_buffer, s->decode_buffer_size, 1);
454 /* render the final PAL8 frame */
455 if (s->vector_height == 4)
459 for (y = 0; y < s->frame.linesize[0] * s->height;
460 y += s->frame.linesize[0] * s->vector_height) {
462 for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
465 /* get the vector index, the method for which varies according to
466 * VQA file version */
467 switch (s->vqa_version) {
470 /* still need sample media for this case (only one game, "Legend of
471 * Kyrandia III : Malcolm's Revenge", is known to use this version) */
472 lobyte = s->decode_buffer[lobytes * 2];
473 hibyte = s->decode_buffer[(lobytes * 2) + 1];
474 vector_index = ((hibyte << 8) | lobyte) >> 3;
475 vector_index <<= index_shift;
476 lines = s->vector_height;
477 /* uniform color fill - a quick hack */
478 if (hibyte == 0xFF) {
480 s->frame.data[0][pixel_ptr + 0] = 255 - lobyte;
481 s->frame.data[0][pixel_ptr + 1] = 255 - lobyte;
482 s->frame.data[0][pixel_ptr + 2] = 255 - lobyte;
483 s->frame.data[0][pixel_ptr + 3] = 255 - lobyte;
484 pixel_ptr += s->frame.linesize[0];
491 lobyte = s->decode_buffer[lobytes];
492 hibyte = s->decode_buffer[hibytes];
493 vector_index = (hibyte << 8) | lobyte;
494 vector_index <<= index_shift;
495 lines = s->vector_height;
499 /* not implemented yet */
505 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
506 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
507 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
508 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
509 pixel_ptr += s->frame.linesize[0];
514 /* handle partial codebook */
515 if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
516 /* a chunk should not have both chunk types */
517 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
521 if (cbp0_chunk != -1) {
523 chunk_size = AV_RB32(&s->buf[cbp0_chunk + 4]);
524 cbp0_chunk += CHUNK_PREAMBLE_SIZE;
526 /* accumulate partial codebook */
527 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
528 &s->buf[cbp0_chunk], chunk_size);
529 s->next_codebook_buffer_index += chunk_size;
531 s->partial_countdown--;
532 if (s->partial_countdown == 0) {
534 /* time to replace codebook */
535 memcpy(s->codebook, s->next_codebook_buffer,
536 s->next_codebook_buffer_index);
538 /* reset accounting */
539 s->next_codebook_buffer_index = 0;
540 s->partial_countdown = s->partial_count;
544 if (cbpz_chunk != -1) {
546 chunk_size = AV_RB32(&s->buf[cbpz_chunk + 4]);
547 cbpz_chunk += CHUNK_PREAMBLE_SIZE;
549 /* accumulate partial codebook */
550 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
551 &s->buf[cbpz_chunk], chunk_size);
552 s->next_codebook_buffer_index += chunk_size;
554 s->partial_countdown--;
555 if (s->partial_countdown == 0) {
557 /* decompress codebook */
558 decode_format80(s->next_codebook_buffer,
559 s->next_codebook_buffer_index,
560 s->codebook, s->codebook_size, 0);
562 /* reset accounting */
563 s->next_codebook_buffer_index = 0;
564 s->partial_countdown = s->partial_count;
569 static int vqa_decode_frame(AVCodecContext *avctx,
570 void *data, int *data_size,
571 uint8_t *buf, int buf_size)
573 VqaContext *s = avctx->priv_data;
578 if (s->frame.data[0])
579 avctx->release_buffer(avctx, &s->frame);
581 if (avctx->get_buffer(avctx, &s->frame)) {
582 av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
588 /* make the palette available on the way out */
589 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
590 s->frame.palette_has_changed = 1;
592 *data_size = sizeof(AVFrame);
593 *(AVFrame*)data = s->frame;
595 /* report that the buffer was completely consumed */
599 static int vqa_decode_end(AVCodecContext *avctx)
601 VqaContext *s = avctx->priv_data;
603 av_free(s->codebook);
604 av_free(s->next_codebook_buffer);
605 av_free(s->decode_buffer);
607 if (s->frame.data[0])
608 avctx->release_buffer(avctx, &s->frame);
613 AVCodec vqa_decoder = {