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 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
= LE_16(&src
[src_index
]);
235 src_pos
= LE_16(&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
= LE_16(&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
= LE_16(&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
= BE_16(&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
= BE_32(&s
->buf
[index
]);
328 chunk_size
= BE_32(&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
= BE_32(&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
= BE_32(&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
= BE_32(&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
= BE_32(&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) */
476 lobyte
= s
->decode_buffer
[lobytes
];
477 hibyte
= s
->decode_buffer
[hibytes
];
478 vector_index
= (hibyte
<< 8) | lobyte
;
479 vector_index
<<= index_shift
;
480 lines
= s
->vector_height
;
484 /* not implemented yet */
490 s
->frame
.data
[0][pixel_ptr
+ 0] = s
->codebook
[vector_index
++];
491 s
->frame
.data
[0][pixel_ptr
+ 1] = s
->codebook
[vector_index
++];
492 s
->frame
.data
[0][pixel_ptr
+ 2] = s
->codebook
[vector_index
++];
493 s
->frame
.data
[0][pixel_ptr
+ 3] = s
->codebook
[vector_index
++];
494 pixel_ptr
+= s
->frame
.linesize
[0];
499 /* handle partial codebook */
500 if ((cbp0_chunk
!= -1) && (cbpz_chunk
!= -1)) {
501 /* a chunk should not have both chunk types */
502 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
506 if (cbp0_chunk
!= -1) {
508 chunk_size
= BE_32(&s
->buf
[cbp0_chunk
+ 4]);
509 cbp0_chunk
+= CHUNK_PREAMBLE_SIZE
;
511 /* accumulate partial codebook */
512 memcpy(&s
->next_codebook_buffer
[s
->next_codebook_buffer_index
],
513 &s
->buf
[cbp0_chunk
], chunk_size
);
514 s
->next_codebook_buffer_index
+= chunk_size
;
516 s
->partial_countdown
--;
517 if (s
->partial_countdown
== 0) {
519 /* time to replace codebook */
520 memcpy(s
->codebook
, s
->next_codebook_buffer
,
521 s
->next_codebook_buffer_index
);
523 /* reset accounting */
524 s
->next_codebook_buffer_index
= 0;
525 s
->partial_countdown
= s
->partial_count
;
529 if (cbpz_chunk
!= -1) {
531 chunk_size
= BE_32(&s
->buf
[cbpz_chunk
+ 4]);
532 cbpz_chunk
+= CHUNK_PREAMBLE_SIZE
;
534 /* accumulate partial codebook */
535 memcpy(&s
->next_codebook_buffer
[s
->next_codebook_buffer_index
],
536 &s
->buf
[cbpz_chunk
], chunk_size
);
537 s
->next_codebook_buffer_index
+= chunk_size
;
539 s
->partial_countdown
--;
540 if (s
->partial_countdown
== 0) {
542 /* decompress codebook */
543 decode_format80(s
->next_codebook_buffer
,
544 s
->next_codebook_buffer_index
,
545 s
->codebook
, s
->codebook_size
, 0);
547 /* reset accounting */
548 s
->next_codebook_buffer_index
= 0;
549 s
->partial_countdown
= s
->partial_count
;
554 static int vqa_decode_frame(AVCodecContext
*avctx
,
555 void *data
, int *data_size
,
556 uint8_t *buf
, int buf_size
)
558 VqaContext
*s
= (VqaContext
*)avctx
->priv_data
;
563 if (s
->frame
.data
[0])
564 avctx
->release_buffer(avctx
, &s
->frame
);
566 if (avctx
->get_buffer(avctx
, &s
->frame
)) {
567 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA Video: get_buffer() failed\n");
573 /* make the palette available on the way out */
574 memcpy(s
->frame
.data
[1], s
->palette
, PALETTE_COUNT
* 4);
575 s
->frame
.palette_has_changed
= 1;
577 *data_size
= sizeof(AVFrame
);
578 *(AVFrame
*)data
= s
->frame
;
580 /* report that the buffer was completely consumed */
584 static int vqa_decode_end(AVCodecContext
*avctx
)
586 VqaContext
*s
= (VqaContext
*)avctx
->priv_data
;
588 av_free(s
->codebook
);
589 av_free(s
->next_codebook_buffer
);
590 av_free(s
->decode_buffer
);
592 if (s
->frame
.data
[0])
593 avctx
->release_buffer(avctx
, &s
->frame
);
598 AVCodec vqa_decoder
= {