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
76 #define PALETTE_COUNT 256
77 #define VQA_HEADER_SIZE 0x2A
78 #define CHUNK_PREAMBLE_SIZE 8
80 /* allocate the maximum vector space, regardless of the file version:
81 * (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
82 #define MAX_CODEBOOK_VECTORS 0xFF00
83 #define SOLID_PIXEL_VECTORS 0x100
84 #define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
85 #define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)
87 #define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
88 #define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
89 #define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
90 #define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
91 #define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
92 #define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
93 #define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')
98 #define vqa_debug printf
100 static inline void vqa_debug(const char *format, ...) { }
103 typedef struct VqaContext {
105 AVCodecContext *avctx;
112 uint32_t palette[PALETTE_COUNT];
114 int width; /* width of a frame */
115 int height; /* height of a frame */
116 int vector_width; /* width of individual vector */
117 int vector_height; /* height of individual vector */
118 int vqa_version; /* this should be either 1, 2 or 3 */
120 unsigned char *codebook; /* the current codebook */
122 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
123 int next_codebook_buffer_index;
125 unsigned char *decode_buffer;
126 int decode_buffer_size;
128 /* number of frames to go before replacing codebook */
129 int partial_countdown;
134 static int vqa_decode_init(AVCodecContext *avctx)
136 VqaContext *s = (VqaContext *)avctx->priv_data;
137 unsigned char *vqa_header;
138 int i, j, codebook_index;;
141 avctx->pix_fmt = PIX_FMT_PAL8;
142 avctx->has_b_frames = 0;
143 dsputil_init(&s->dsp, avctx);
145 /* make sure the extradata made it */
146 if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
147 av_log(s->avctx, AV_LOG_ERROR, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);
151 /* load up the VQA parameters from the header */
152 vqa_header = (unsigned char *)s->avctx->extradata;
153 s->vqa_version = vqa_header[0];
154 s->width = AV_RL16(&vqa_header[6]);
155 s->height = AV_RL16(&vqa_header[8]);
156 if(avcodec_check_dimensions(avctx, s->width, s->height)){
157 s->width= s->height= 0;
160 s->vector_width = vqa_header[10];
161 s->vector_height = vqa_header[11];
162 s->partial_count = s->partial_countdown = vqa_header[13];
164 /* the vector dimensions have to meet very stringent requirements */
165 if ((s->vector_width != 4) ||
166 ((s->vector_height != 2) && (s->vector_height != 4))) {
167 /* return without further initialization */
171 /* allocate codebooks */
172 s->codebook_size = MAX_CODEBOOK_SIZE;
173 s->codebook = av_malloc(s->codebook_size);
174 s->next_codebook_buffer = av_malloc(s->codebook_size);
176 /* initialize the solid-color vectors */
177 if (s->vector_height == 4) {
178 codebook_index = 0xFF00 * 16;
179 for (i = 0; i < 256; i++)
180 for (j = 0; j < 16; j++)
181 s->codebook[codebook_index++] = i;
183 codebook_index = 0xF00 * 8;
184 for (i = 0; i < 256; i++)
185 for (j = 0; j < 8; j++)
186 s->codebook[codebook_index++] = i;
188 s->next_codebook_buffer_index = 0;
190 /* allocate decode buffer */
191 s->decode_buffer_size = (s->width / s->vector_width) *
192 (s->height / s->vector_height) * 2;
193 s->decode_buffer = av_malloc(s->decode_buffer_size);
195 s->frame.data[0] = NULL;
200 #define CHECK_COUNT() \
201 if (dest_index + count > dest_size) { \
202 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
203 av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
204 dest_index, count, dest_size); \
208 static void decode_format80(unsigned char *src, int src_size,
209 unsigned char *dest, int dest_size, int check_size) {
218 while (src_index < src_size) {
220 vqa_debug(" opcode %02X: ", src[src_index]);
222 /* 0x80 means that frame is finished */
223 if (src[src_index] == 0x80)
226 if (dest_index >= dest_size) {
227 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
228 dest_index, dest_size);
232 if (src[src_index] == 0xFF) {
235 count = AV_RL16(&src[src_index]);
237 src_pos = AV_RL16(&src[src_index]);
239 vqa_debug("(1) copy %X bytes from absolute pos %X\n", count, src_pos);
241 for (i = 0; i < count; i++)
242 dest[dest_index + i] = dest[src_pos + i];
245 } else if (src[src_index] == 0xFE) {
248 count = AV_RL16(&src[src_index]);
250 color = src[src_index++];
251 vqa_debug("(2) set %X bytes to %02X\n", count, color);
253 memset(&dest[dest_index], color, count);
256 } else if ((src[src_index] & 0xC0) == 0xC0) {
258 count = (src[src_index++] & 0x3F) + 3;
259 src_pos = AV_RL16(&src[src_index]);
261 vqa_debug("(3) copy %X bytes from absolute pos %X\n", count, src_pos);
263 for (i = 0; i < count; i++)
264 dest[dest_index + i] = dest[src_pos + i];
267 } else if (src[src_index] > 0x80) {
269 count = src[src_index++] & 0x3F;
270 vqa_debug("(4) copy %X bytes from source to dest\n", count);
272 memcpy(&dest[dest_index], &src[src_index], count);
278 count = ((src[src_index] & 0x70) >> 4) + 3;
279 src_pos = AV_RB16(&src[src_index]) & 0x0FFF;
281 vqa_debug("(5) copy %X bytes from relpos %X\n", count, src_pos);
283 for (i = 0; i < count; i++)
284 dest[dest_index + i] = dest[dest_index - src_pos + i];
289 /* validate that the entire destination buffer was filled; this is
290 * important for decoding frame maps since each vector needs to have a
291 * codebook entry; it is not important for compressed codebooks because
292 * not every entry needs to be filled */
294 if (dest_index < dest_size)
295 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
296 dest_index, dest_size);
299 static void vqa_decode_chunk(VqaContext *s)
301 unsigned int chunk_type;
302 unsigned int chunk_size;
304 unsigned int index = 0;
306 unsigned char r, g, b;
320 int vector_index = 0;
324 int hibytes = s->decode_buffer_size / 2;
326 /* first, traverse through the frame and find the subchunks */
327 while (index < s->size) {
329 chunk_type = AV_RB32(&s->buf[index]);
330 chunk_size = AV_RB32(&s->buf[index + 4]);
332 switch (chunk_type) {
363 av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
364 (chunk_type >> 24) & 0xFF,
365 (chunk_type >> 16) & 0xFF,
366 (chunk_type >> 8) & 0xFF,
367 (chunk_type >> 0) & 0xFF,
372 byte_skip = chunk_size & 0x01;
373 index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
376 /* next, deal with the palette */
377 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
379 /* a chunk should not have both chunk types */
380 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
384 /* decompress the palette chunk */
385 if (cplz_chunk != -1) {
387 /* yet to be handled */
391 /* convert the RGB palette into the machine's endian format */
392 if (cpl0_chunk != -1) {
394 chunk_size = AV_RB32(&s->buf[cpl0_chunk + 4]);
395 /* sanity check the palette size */
396 if (chunk_size / 3 > 256) {
397 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
401 cpl0_chunk += CHUNK_PREAMBLE_SIZE;
402 for (i = 0; i < chunk_size / 3; i++) {
403 /* scale by 4 to transform 6-bit palette -> 8-bit */
404 r = s->buf[cpl0_chunk++] * 4;
405 g = s->buf[cpl0_chunk++] * 4;
406 b = s->buf[cpl0_chunk++] * 4;
407 s->palette[i] = (r << 16) | (g << 8) | (b);
411 /* next, look for a full codebook */
412 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
414 /* a chunk should not have both chunk types */
415 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
419 /* decompress the full codebook chunk */
420 if (cbfz_chunk != -1) {
422 chunk_size = AV_RB32(&s->buf[cbfz_chunk + 4]);
423 cbfz_chunk += CHUNK_PREAMBLE_SIZE;
424 decode_format80(&s->buf[cbfz_chunk], chunk_size,
425 s->codebook, s->codebook_size, 0);
428 /* copy a full codebook */
429 if (cbf0_chunk != -1) {
431 chunk_size = AV_RB32(&s->buf[cbf0_chunk + 4]);
432 /* sanity check the full codebook size */
433 if (chunk_size > MAX_CODEBOOK_SIZE) {
434 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
438 cbf0_chunk += CHUNK_PREAMBLE_SIZE;
440 memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
443 /* decode the frame */
444 if (vptz_chunk == -1) {
446 /* something is wrong if there is no VPTZ chunk */
447 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
451 chunk_size = AV_RB32(&s->buf[vptz_chunk + 4]);
452 vptz_chunk += CHUNK_PREAMBLE_SIZE;
453 decode_format80(&s->buf[vptz_chunk], chunk_size,
454 s->decode_buffer, s->decode_buffer_size, 1);
456 /* render the final PAL8 frame */
457 if (s->vector_height == 4)
461 for (y = 0; y < s->frame.linesize[0] * s->height;
462 y += s->frame.linesize[0] * s->vector_height) {
464 for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
467 /* get the vector index, the method for which varies according to
468 * VQA file version */
469 switch (s->vqa_version) {
472 /* still need sample media for this case (only one game, "Legend of
473 * Kyrandia III : Malcolm's Revenge", is known to use this version) */
474 lobyte = s->decode_buffer[lobytes * 2];
475 hibyte = s->decode_buffer[(lobytes * 2) + 1];
476 vector_index = ((hibyte << 8) | lobyte) >> 3;
477 vector_index <<= index_shift;
478 lines = s->vector_height;
479 /* uniform color fill - a quick hack */
480 if (hibyte == 0xFF) {
482 s->frame.data[0][pixel_ptr + 0] = 255 - lobyte;
483 s->frame.data[0][pixel_ptr + 1] = 255 - lobyte;
484 s->frame.data[0][pixel_ptr + 2] = 255 - lobyte;
485 s->frame.data[0][pixel_ptr + 3] = 255 - lobyte;
486 pixel_ptr += s->frame.linesize[0];
493 lobyte = s->decode_buffer[lobytes];
494 hibyte = s->decode_buffer[hibytes];
495 vector_index = (hibyte << 8) | lobyte;
496 vector_index <<= index_shift;
497 lines = s->vector_height;
501 /* not implemented yet */
507 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
508 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
509 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
510 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
511 pixel_ptr += s->frame.linesize[0];
516 /* handle partial codebook */
517 if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
518 /* a chunk should not have both chunk types */
519 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
523 if (cbp0_chunk != -1) {
525 chunk_size = AV_RB32(&s->buf[cbp0_chunk + 4]);
526 cbp0_chunk += CHUNK_PREAMBLE_SIZE;
528 /* accumulate partial codebook */
529 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
530 &s->buf[cbp0_chunk], chunk_size);
531 s->next_codebook_buffer_index += chunk_size;
533 s->partial_countdown--;
534 if (s->partial_countdown == 0) {
536 /* time to replace codebook */
537 memcpy(s->codebook, s->next_codebook_buffer,
538 s->next_codebook_buffer_index);
540 /* reset accounting */
541 s->next_codebook_buffer_index = 0;
542 s->partial_countdown = s->partial_count;
546 if (cbpz_chunk != -1) {
548 chunk_size = AV_RB32(&s->buf[cbpz_chunk + 4]);
549 cbpz_chunk += CHUNK_PREAMBLE_SIZE;
551 /* accumulate partial codebook */
552 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
553 &s->buf[cbpz_chunk], chunk_size);
554 s->next_codebook_buffer_index += chunk_size;
556 s->partial_countdown--;
557 if (s->partial_countdown == 0) {
559 /* decompress codebook */
560 decode_format80(s->next_codebook_buffer,
561 s->next_codebook_buffer_index,
562 s->codebook, s->codebook_size, 0);
564 /* reset accounting */
565 s->next_codebook_buffer_index = 0;
566 s->partial_countdown = s->partial_count;
571 static int vqa_decode_frame(AVCodecContext *avctx,
572 void *data, int *data_size,
573 uint8_t *buf, int buf_size)
575 VqaContext *s = (VqaContext *)avctx->priv_data;
580 if (s->frame.data[0])
581 avctx->release_buffer(avctx, &s->frame);
583 if (avctx->get_buffer(avctx, &s->frame)) {
584 av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
590 /* make the palette available on the way out */
591 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
592 s->frame.palette_has_changed = 1;
594 *data_size = sizeof(AVFrame);
595 *(AVFrame*)data = s->frame;
597 /* report that the buffer was completely consumed */
601 static int vqa_decode_end(AVCodecContext *avctx)
603 VqaContext *s = (VqaContext *)avctx->priv_data;
605 av_free(s->codebook);
606 av_free(s->next_codebook_buffer);
607 av_free(s->decode_buffer);
609 if (s->frame.data[0])
610 avctx->release_buffer(avctx, &s->frame);
615 AVCodec vqa_decoder = {