2 * Westwood Studios VQA 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 * VQA Video Decoder by Mike Melanson (melanson@pcisys.net)
24 * For more information about the RPZA format, visit:
25 * http://www.pcisys.net/~melanson/codecs/
27 * The VQA video decoder outputs PAL8 or RGB555 colorspace data, depending
28 * on the type of data in the file.
30 * This decoder needs the 42-byte VQHD header from the beginning
31 * of the VQA file passed through the extradata field. The VQHD header
34 * bytes 0-3 chunk fourcc: 'VQHD'
35 * bytes 4-7 chunk size in big-endian format, should be 0x0000002A
36 * bytes 8-49 VQHD chunk data
38 * Bytes 8-49 are what this decoder expects to see.
40 * Briefly, VQA is a vector quantized animation format that operates in a
41 * VGA palettized colorspace. It operates on pixel vectors (blocks)
42 * of either 4x2 or 4x4 in size. Compressed VQA chunks can contain vector
43 * codebooks, palette information, and code maps for rendering vectors onto
44 * frames. Any of these components can also be compressed with a run-length
45 * encoding (RLE) algorithm commonly referred to as "format80".
47 * VQA takes a novel approach to rate control. Each group of n frames
48 * (usually, n = 8) relies on a different vector codebook. Rather than
49 * transporting an entire codebook every 8th frame, the new codebook is
50 * broken up into 8 pieces and sent along with the compressed video chunks
51 * for each of the 8 frames preceding the 8 frames which require the
52 * codebook. A full codebook is also sent on the very first frame of a
53 * file. This is an interesting technique, although it makes random file
54 * seeking difficult despite the fact that the frames are all intracoded.
56 * V1,2 VQA uses 12-bit codebook indices. If the 12-bit indices were
57 * packed into bytes and then RLE compressed, bytewise, the results would
58 * be poor. That is why the coding method divides each index into 2 parts,
59 * the top 4 bits and the bottom 8 bits, then RL encodes the 4-bit pieces
60 * together and the 8-bit pieces together. If most of the vectors are
61 * clustered into one group of 256 vectors, most of the 4-bit index pieces
74 #define PALETTE_COUNT 256
75 #define VQA_HEADER_SIZE 0x2A
76 #define CHUNK_PREAMBLE_SIZE 8
78 /* allocate the maximum vector space, regardless of the file version:
79 * (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
80 #define MAX_CODEBOOK_VECTORS 0xFF00
81 #define SOLID_PIXEL_VECTORS 0x100
82 #define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
83 #define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)
85 #define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
86 #define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
87 #define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
88 #define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
89 #define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
90 #define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
91 #define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')
96 #define vqa_debug printf
98 static inline void vqa_debug(const char *format, ...) { }
101 typedef struct VqaContext {
103 AVCodecContext *avctx;
110 unsigned int palette[PALETTE_COUNT];
112 int width; /* width of a frame */
113 int height; /* height of a frame */
114 int vector_width; /* width of individual vector */
115 int vector_height; /* height of individual vector */
116 int vqa_version; /* this should be either 1, 2 or 3 */
118 unsigned char *codebook; /* the current codebook */
120 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
121 int next_codebook_buffer_index;
123 unsigned char *decode_buffer;
124 int decode_buffer_size;
126 /* number of frames to go before replacing codebook */
127 int partial_countdown;
132 static int vqa_decode_init(AVCodecContext *avctx)
134 VqaContext *s = (VqaContext *)avctx->priv_data;
135 unsigned char *vqa_header;
136 int i, j, codebook_index;;
139 avctx->pix_fmt = PIX_FMT_PAL8;
140 avctx->has_b_frames = 0;
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 = LE_16(&vqa_header[6]);
153 s->height = LE_16(&vqa_header[8]);
154 s->vector_width = vqa_header[10];
155 s->vector_height = vqa_header[11];
156 s->partial_count = s->partial_countdown = vqa_header[13];
158 /* the vector dimensions have to meet very stringent requirements */
159 if ((s->vector_width != 4) ||
160 ((s->vector_height != 2) && (s->vector_height != 4))) {
161 /* return without further initialization */
165 /* allocate codebooks */
166 s->codebook_size = MAX_CODEBOOK_SIZE;
167 s->codebook = av_malloc(s->codebook_size);
168 s->next_codebook_buffer = av_malloc(s->codebook_size);
170 /* initialize the solid-color vectors */
171 if (s->vector_height == 4) {
172 codebook_index = 0xFF00 * 16;
173 for (i = 0; i < 256; i++)
174 for (j = 0; j < 16; j++)
175 s->codebook[codebook_index++] = i;
177 codebook_index = 0xF00 * 8;
178 for (i = 0; i < 256; i++)
179 for (j = 0; j < 8; j++)
180 s->codebook[codebook_index++] = i;
182 s->next_codebook_buffer_index = 0;
184 /* allocate decode buffer */
185 s->decode_buffer_size = (s->width / s->vector_width) *
186 (s->height / s->vector_height) * 2;
187 s->decode_buffer = av_malloc(s->decode_buffer_size);
189 s->frame.data[0] = NULL;
194 #define CHECK_COUNT() \
195 if (dest_index + count > dest_size) { \
196 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
197 av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
198 dest_index, count, dest_size); \
202 static void decode_format80(unsigned char *src, int src_size,
203 unsigned char *dest, int dest_size, int check_size) {
212 while (src_index < src_size) {
214 vqa_debug(" opcode %02X: ", src[src_index]);
216 /* 0x80 means that frame is finished */
217 if (src[src_index] == 0x80)
220 if (dest_index >= dest_size) {
221 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
222 dest_index, dest_size);
226 if (src[src_index] == 0xFF) {
229 count = LE_16(&src[src_index]);
231 src_pos = LE_16(&src[src_index]);
233 vqa_debug("(1) copy %X bytes from absolute pos %X\n", count, src_pos);
235 for (i = 0; i < count; i++)
236 dest[dest_index + i] = dest[src_pos + i];
239 } else if (src[src_index] == 0xFE) {
242 count = LE_16(&src[src_index]);
244 color = src[src_index++];
245 vqa_debug("(2) set %X bytes to %02X\n", count, color);
247 memset(&dest[dest_index], color, count);
250 } else if ((src[src_index] & 0xC0) == 0xC0) {
252 count = (src[src_index++] & 0x3F) + 3;
253 src_pos = LE_16(&src[src_index]);
255 vqa_debug("(3) copy %X bytes from absolute pos %X\n", count, src_pos);
257 for (i = 0; i < count; i++)
258 dest[dest_index + i] = dest[src_pos + i];
261 } else if (src[src_index] > 0x80) {
263 count = src[src_index++] & 0x3F;
264 vqa_debug("(4) copy %X bytes from source to dest\n", count);
266 memcpy(&dest[dest_index], &src[src_index], count);
272 count = ((src[src_index] & 0x70) >> 4) + 3;
273 src_pos = BE_16(&src[src_index]) & 0x0FFF;
275 vqa_debug("(5) copy %X bytes from relpos %X\n", count, src_pos);
277 for (i = 0; i < count; i++)
278 dest[dest_index + i] = dest[dest_index - src_pos + i];
283 /* validate that the entire destination buffer was filled; this is
284 * important for decoding frame maps since each vector needs to have a
285 * codebook entry; it is not important for compressed codebooks because
286 * not every entry needs to be filled */
288 if (dest_index < dest_size)
289 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
290 dest_index, dest_size);
293 static void vqa_decode_chunk(VqaContext *s)
295 unsigned int chunk_type;
296 unsigned int chunk_size;
298 unsigned int index = 0;
300 unsigned char r, g, b;
314 int vector_index = 0;
318 int hibytes = s->decode_buffer_size / 2;
320 /* first, traverse through the frame and find the subchunks */
321 while (index < s->size) {
323 chunk_type = BE_32(&s->buf[index]);
324 chunk_size = BE_32(&s->buf[index + 4]);
326 switch (chunk_type) {
357 av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
358 (chunk_type >> 24) & 0xFF,
359 (chunk_type >> 16) & 0xFF,
360 (chunk_type >> 8) & 0xFF,
361 (chunk_type >> 0) & 0xFF,
366 byte_skip = chunk_size & 0x01;
367 index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
370 /* next, deal with the palette */
371 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
373 /* a chunk should not have both chunk types */
374 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
378 /* decompress the palette chunk */
379 if (cplz_chunk != -1) {
381 /* yet to be handled */
385 /* convert the RGB palette into the machine's endian format */
386 if (cpl0_chunk != -1) {
388 chunk_size = BE_32(&s->buf[cpl0_chunk + 4]);
389 /* sanity check the palette size */
390 if (chunk_size / 3 > 256) {
391 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
395 cpl0_chunk += CHUNK_PREAMBLE_SIZE;
396 for (i = 0; i < chunk_size / 3; i++) {
397 /* scale by 4 to transform 6-bit palette -> 8-bit */
398 r = s->buf[cpl0_chunk++] * 4;
399 g = s->buf[cpl0_chunk++] * 4;
400 b = s->buf[cpl0_chunk++] * 4;
401 s->palette[i] = (r << 16) | (g << 8) | (b);
405 /* next, look for a full codebook */
406 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
408 /* a chunk should not have both chunk types */
409 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
413 /* decompress the full codebook chunk */
414 if (cbfz_chunk != -1) {
416 chunk_size = BE_32(&s->buf[cbfz_chunk + 4]);
417 cbfz_chunk += CHUNK_PREAMBLE_SIZE;
418 decode_format80(&s->buf[cbfz_chunk], chunk_size,
419 s->codebook, s->codebook_size, 0);
422 /* copy a full codebook */
423 if (cbf0_chunk != -1) {
425 chunk_size = BE_32(&s->buf[cbf0_chunk + 4]);
426 /* sanity check the full codebook size */
427 if (chunk_size > MAX_CODEBOOK_SIZE) {
428 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
432 cbf0_chunk += CHUNK_PREAMBLE_SIZE;
434 memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
437 /* decode the frame */
438 if (vptz_chunk == -1) {
440 /* something is wrong if there is no VPTZ chunk */
441 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
445 chunk_size = BE_32(&s->buf[vptz_chunk + 4]);
446 vptz_chunk += CHUNK_PREAMBLE_SIZE;
447 decode_format80(&s->buf[vptz_chunk], chunk_size,
448 s->decode_buffer, s->decode_buffer_size, 1);
450 /* render the final PAL8 frame */
451 if (s->vector_height == 4)
455 for (y = 0; y < s->frame.linesize[0] * s->height;
456 y += s->frame.linesize[0] * s->vector_height) {
458 for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
461 /* get the vector index, the method for which varies according to
462 * VQA file version */
463 switch (s->vqa_version) {
466 /* still need sample media for this case (only one game, "Legend of
467 * Kyrandia III : Malcolm's Revenge", is known to use this version) */
472 lobyte = s->decode_buffer[lobytes];
473 hibyte = s->decode_buffer[hibytes];
474 vector_index = (hibyte << 8) | lobyte;
475 vector_index <<= index_shift;
476 lines = s->vector_height;
480 /* not implemented yet */
486 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
487 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
488 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
489 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
490 pixel_ptr += s->frame.linesize[0];
495 /* handle partial codebook */
496 if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
497 /* a chunk should not have both chunk types */
498 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
502 if (cbp0_chunk != -1) {
504 chunk_size = BE_32(&s->buf[cbp0_chunk + 4]);
505 cbp0_chunk += CHUNK_PREAMBLE_SIZE;
507 /* accumulate partial codebook */
508 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
509 &s->buf[cbp0_chunk], chunk_size);
510 s->next_codebook_buffer_index += chunk_size;
512 s->partial_countdown--;
513 if (s->partial_countdown == 0) {
515 /* time to replace codebook */
516 memcpy(s->codebook, s->next_codebook_buffer,
517 s->next_codebook_buffer_index);
519 /* reset accounting */
520 s->next_codebook_buffer_index = 0;
521 s->partial_countdown = s->partial_count;
525 if (cbpz_chunk != -1) {
527 chunk_size = BE_32(&s->buf[cbpz_chunk + 4]);
528 cbpz_chunk += CHUNK_PREAMBLE_SIZE;
530 /* accumulate partial codebook */
531 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
532 &s->buf[cbpz_chunk], chunk_size);
533 s->next_codebook_buffer_index += chunk_size;
535 s->partial_countdown--;
536 if (s->partial_countdown == 0) {
538 /* decompress codebook */
539 decode_format80(s->next_codebook_buffer,
540 s->next_codebook_buffer_index,
541 s->codebook, s->codebook_size, 0);
543 /* reset accounting */
544 s->next_codebook_buffer_index = 0;
545 s->partial_countdown = s->partial_count;
550 static int vqa_decode_frame(AVCodecContext *avctx,
551 void *data, int *data_size,
552 uint8_t *buf, int buf_size)
554 VqaContext *s = (VqaContext *)avctx->priv_data;
559 if (s->frame.data[0])
560 avctx->release_buffer(avctx, &s->frame);
562 if (avctx->get_buffer(avctx, &s->frame)) {
563 av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
569 /* make the palette available on the way out */
570 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
571 s->frame.palette_has_changed = 1;
573 *data_size = sizeof(AVFrame);
574 *(AVFrame*)data = s->frame;
576 /* report that the buffer was completely consumed */
580 static int vqa_decode_end(AVCodecContext *avctx)
582 VqaContext *s = (VqaContext *)avctx->priv_data;
584 av_free(s->codebook);
585 av_free(s->next_codebook_buffer);
586 av_free(s->decode_buffer);
588 if (s->frame.data[0])
589 avctx->release_buffer(avctx, &s->frame);
594 AVCodec vqa_decoder = {