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
24 * VQA Video Decoder by Mike Melanson (melanson@pcisys.net)
25 * For more information about the VQA format, visit:
26 * http://wiki.multimedia.cx/index.php?title=VQA
28 * The VQA video decoder outputs PAL8 or RGB555 colorspace data, depending
29 * on the type of data in the file.
31 * This decoder needs the 42-byte VQHD header from the beginning
32 * of the VQA file passed through the extradata field. The VQHD header
35 * bytes 0-3 chunk fourcc: 'VQHD'
36 * bytes 4-7 chunk size in big-endian format, should be 0x0000002A
37 * bytes 8-49 VQHD chunk data
39 * Bytes 8-49 are what this decoder expects to see.
41 * Briefly, VQA is a vector quantized animation format that operates in a
42 * VGA palettized colorspace. It operates on pixel vectors (blocks)
43 * of either 4x2 or 4x4 in size. Compressed VQA chunks can contain vector
44 * codebooks, palette information, and code maps for rendering vectors onto
45 * frames. Any of these components can also be compressed with a run-length
46 * encoding (RLE) algorithm commonly referred to as "format80".
48 * VQA takes a novel approach to rate control. Each group of n frames
49 * (usually, n = 8) relies on a different vector codebook. Rather than
50 * transporting an entire codebook every 8th frame, the new codebook is
51 * broken up into 8 pieces and sent along with the compressed video chunks
52 * for each of the 8 frames preceding the 8 frames which require the
53 * codebook. A full codebook is also sent on the very first frame of a
54 * file. This is an interesting technique, although it makes random file
55 * seeking difficult despite the fact that the frames are all intracoded.
57 * V1,2 VQA uses 12-bit codebook indices. If the 12-bit indices were
58 * packed into bytes and then RLE compressed, bytewise, the results would
59 * be poor. That is why the coding method divides each index into 2 parts,
60 * the top 4 bits and the bottom 8 bits, then RL encodes the 4-bit pieces
61 * together and the 8-bit pieces together. If most of the vectors are
62 * 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 uint32_t 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
= avctx
->priv_data
;
135 unsigned char *vqa_header
;
136 int i
, j
, codebook_index
;;
139 avctx
->pix_fmt
= PIX_FMT_PAL8
;
140 dsputil_init(&s
->dsp
, avctx
);
142 /* make sure the extradata made it */
143 if (s
->avctx
->extradata_size
!= VQA_HEADER_SIZE
) {
144 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE
);
148 /* load up the VQA parameters from the header */
149 vqa_header
= (unsigned char *)s
->avctx
->extradata
;
150 s
->vqa_version
= vqa_header
[0];
151 s
->width
= AV_RL16(&vqa_header
[6]);
152 s
->height
= AV_RL16(&vqa_header
[8]);
153 if(avcodec_check_dimensions(avctx
, s
->width
, s
->height
)){
154 s
->width
= s
->height
= 0;
157 s
->vector_width
= vqa_header
[10];
158 s
->vector_height
= vqa_header
[11];
159 s
->partial_count
= s
->partial_countdown
= vqa_header
[13];
161 /* the vector dimensions have to meet very stringent requirements */
162 if ((s
->vector_width
!= 4) ||
163 ((s
->vector_height
!= 2) && (s
->vector_height
!= 4))) {
164 /* return without further initialization */
168 /* allocate codebooks */
169 s
->codebook_size
= MAX_CODEBOOK_SIZE
;
170 s
->codebook
= av_malloc(s
->codebook_size
);
171 s
->next_codebook_buffer
= av_malloc(s
->codebook_size
);
173 /* initialize the solid-color vectors */
174 if (s
->vector_height
== 4) {
175 codebook_index
= 0xFF00 * 16;
176 for (i
= 0; i
< 256; i
++)
177 for (j
= 0; j
< 16; j
++)
178 s
->codebook
[codebook_index
++] = i
;
180 codebook_index
= 0xF00 * 8;
181 for (i
= 0; i
< 256; i
++)
182 for (j
= 0; j
< 8; j
++)
183 s
->codebook
[codebook_index
++] = i
;
185 s
->next_codebook_buffer_index
= 0;
187 /* allocate decode buffer */
188 s
->decode_buffer_size
= (s
->width
/ s
->vector_width
) *
189 (s
->height
/ s
->vector_height
) * 2;
190 s
->decode_buffer
= av_malloc(s
->decode_buffer_size
);
192 s
->frame
.data
[0] = NULL
;
197 #define CHECK_COUNT() \
198 if (dest_index + count > dest_size) { \
199 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
200 av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
201 dest_index, count, dest_size); \
205 static void decode_format80(unsigned char *src
, int src_size
,
206 unsigned char *dest
, int dest_size
, int check_size
) {
215 while (src_index
< src_size
) {
217 vqa_debug(" opcode %02X: ", src
[src_index
]);
219 /* 0x80 means that frame is finished */
220 if (src
[src_index
] == 0x80)
223 if (dest_index
>= dest_size
) {
224 av_log(NULL
, AV_LOG_ERROR
, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
225 dest_index
, dest_size
);
229 if (src
[src_index
] == 0xFF) {
232 count
= AV_RL16(&src
[src_index
]);
234 src_pos
= AV_RL16(&src
[src_index
]);
236 vqa_debug("(1) copy %X bytes from absolute pos %X\n", count
, src_pos
);
238 for (i
= 0; i
< count
; i
++)
239 dest
[dest_index
+ i
] = dest
[src_pos
+ i
];
242 } else if (src
[src_index
] == 0xFE) {
245 count
= AV_RL16(&src
[src_index
]);
247 color
= src
[src_index
++];
248 vqa_debug("(2) set %X bytes to %02X\n", count
, color
);
250 memset(&dest
[dest_index
], color
, count
);
253 } else if ((src
[src_index
] & 0xC0) == 0xC0) {
255 count
= (src
[src_index
++] & 0x3F) + 3;
256 src_pos
= AV_RL16(&src
[src_index
]);
258 vqa_debug("(3) copy %X bytes from absolute pos %X\n", count
, src_pos
);
260 for (i
= 0; i
< count
; i
++)
261 dest
[dest_index
+ i
] = dest
[src_pos
+ i
];
264 } else if (src
[src_index
] > 0x80) {
266 count
= src
[src_index
++] & 0x3F;
267 vqa_debug("(4) copy %X bytes from source to dest\n", count
);
269 memcpy(&dest
[dest_index
], &src
[src_index
], count
);
275 count
= ((src
[src_index
] & 0x70) >> 4) + 3;
276 src_pos
= AV_RB16(&src
[src_index
]) & 0x0FFF;
278 vqa_debug("(5) copy %X bytes from relpos %X\n", count
, src_pos
);
280 for (i
= 0; i
< count
; i
++)
281 dest
[dest_index
+ i
] = dest
[dest_index
- src_pos
+ i
];
286 /* validate that the entire destination buffer was filled; this is
287 * important for decoding frame maps since each vector needs to have a
288 * codebook entry; it is not important for compressed codebooks because
289 * not every entry needs to be filled */
291 if (dest_index
< dest_size
)
292 av_log(NULL
, AV_LOG_ERROR
, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
293 dest_index
, dest_size
);
296 static void vqa_decode_chunk(VqaContext
*s
)
298 unsigned int chunk_type
;
299 unsigned int chunk_size
;
301 unsigned int index
= 0;
303 unsigned char r
, g
, b
;
317 int vector_index
= 0;
321 int hibytes
= s
->decode_buffer_size
/ 2;
323 /* first, traverse through the frame and find the subchunks */
324 while (index
< s
->size
) {
326 chunk_type
= AV_RB32(&s
->buf
[index
]);
327 chunk_size
= AV_RB32(&s
->buf
[index
+ 4]);
329 switch (chunk_type
) {
360 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
361 (chunk_type
>> 24) & 0xFF,
362 (chunk_type
>> 16) & 0xFF,
363 (chunk_type
>> 8) & 0xFF,
364 (chunk_type
>> 0) & 0xFF,
369 byte_skip
= chunk_size
& 0x01;
370 index
+= (CHUNK_PREAMBLE_SIZE
+ chunk_size
+ byte_skip
);
373 /* next, deal with the palette */
374 if ((cpl0_chunk
!= -1) && (cplz_chunk
!= -1)) {
376 /* a chunk should not have both chunk types */
377 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
381 /* decompress the palette chunk */
382 if (cplz_chunk
!= -1) {
384 /* yet to be handled */
388 /* convert the RGB palette into the machine's endian format */
389 if (cpl0_chunk
!= -1) {
391 chunk_size
= AV_RB32(&s
->buf
[cpl0_chunk
+ 4]);
392 /* sanity check the palette size */
393 if (chunk_size
/ 3 > 256) {
394 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: found a palette chunk with %d colors\n",
398 cpl0_chunk
+= CHUNK_PREAMBLE_SIZE
;
399 for (i
= 0; i
< chunk_size
/ 3; i
++) {
400 /* scale by 4 to transform 6-bit palette -> 8-bit */
401 r
= s
->buf
[cpl0_chunk
++] * 4;
402 g
= s
->buf
[cpl0_chunk
++] * 4;
403 b
= s
->buf
[cpl0_chunk
++] * 4;
404 s
->palette
[i
] = (r
<< 16) | (g
<< 8) | (b
);
408 /* next, look for a full codebook */
409 if ((cbf0_chunk
!= -1) && (cbfz_chunk
!= -1)) {
411 /* a chunk should not have both chunk types */
412 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
416 /* decompress the full codebook chunk */
417 if (cbfz_chunk
!= -1) {
419 chunk_size
= AV_RB32(&s
->buf
[cbfz_chunk
+ 4]);
420 cbfz_chunk
+= CHUNK_PREAMBLE_SIZE
;
421 decode_format80(&s
->buf
[cbfz_chunk
], chunk_size
,
422 s
->codebook
, s
->codebook_size
, 0);
425 /* copy a full codebook */
426 if (cbf0_chunk
!= -1) {
428 chunk_size
= AV_RB32(&s
->buf
[cbf0_chunk
+ 4]);
429 /* sanity check the full codebook size */
430 if (chunk_size
> MAX_CODEBOOK_SIZE
) {
431 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
435 cbf0_chunk
+= CHUNK_PREAMBLE_SIZE
;
437 memcpy(s
->codebook
, &s
->buf
[cbf0_chunk
], chunk_size
);
440 /* decode the frame */
441 if (vptz_chunk
== -1) {
443 /* something is wrong if there is no VPTZ chunk */
444 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: no VPTZ chunk found\n");
448 chunk_size
= AV_RB32(&s
->buf
[vptz_chunk
+ 4]);
449 vptz_chunk
+= CHUNK_PREAMBLE_SIZE
;
450 decode_format80(&s
->buf
[vptz_chunk
], chunk_size
,
451 s
->decode_buffer
, s
->decode_buffer_size
, 1);
453 /* render the final PAL8 frame */
454 if (s
->vector_height
== 4)
458 for (y
= 0; y
< s
->frame
.linesize
[0] * s
->height
;
459 y
+= s
->frame
.linesize
[0] * s
->vector_height
) {
461 for (x
= y
; x
< y
+ s
->width
; x
+= 4, lobytes
++, hibytes
++) {
464 /* get the vector index, the method for which varies according to
465 * VQA file version */
466 switch (s
->vqa_version
) {
469 /* still need sample media for this case (only one game, "Legend of
470 * Kyrandia III : Malcolm's Revenge", is known to use this version) */
471 lobyte
= s
->decode_buffer
[lobytes
* 2];
472 hibyte
= s
->decode_buffer
[(lobytes
* 2) + 1];
473 vector_index
= ((hibyte
<< 8) | lobyte
) >> 3;
474 vector_index
<<= index_shift
;
475 lines
= s
->vector_height
;
476 /* uniform color fill - a quick hack */
477 if (hibyte
== 0xFF) {
479 s
->frame
.data
[0][pixel_ptr
+ 0] = 255 - lobyte
;
480 s
->frame
.data
[0][pixel_ptr
+ 1] = 255 - lobyte
;
481 s
->frame
.data
[0][pixel_ptr
+ 2] = 255 - lobyte
;
482 s
->frame
.data
[0][pixel_ptr
+ 3] = 255 - lobyte
;
483 pixel_ptr
+= s
->frame
.linesize
[0];
490 lobyte
= s
->decode_buffer
[lobytes
];
491 hibyte
= s
->decode_buffer
[hibytes
];
492 vector_index
= (hibyte
<< 8) | lobyte
;
493 vector_index
<<= index_shift
;
494 lines
= s
->vector_height
;
498 /* not implemented yet */
504 s
->frame
.data
[0][pixel_ptr
+ 0] = s
->codebook
[vector_index
++];
505 s
->frame
.data
[0][pixel_ptr
+ 1] = s
->codebook
[vector_index
++];
506 s
->frame
.data
[0][pixel_ptr
+ 2] = s
->codebook
[vector_index
++];
507 s
->frame
.data
[0][pixel_ptr
+ 3] = s
->codebook
[vector_index
++];
508 pixel_ptr
+= s
->frame
.linesize
[0];
513 /* handle partial codebook */
514 if ((cbp0_chunk
!= -1) && (cbpz_chunk
!= -1)) {
515 /* a chunk should not have both chunk types */
516 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
520 if (cbp0_chunk
!= -1) {
522 chunk_size
= AV_RB32(&s
->buf
[cbp0_chunk
+ 4]);
523 cbp0_chunk
+= CHUNK_PREAMBLE_SIZE
;
525 /* accumulate partial codebook */
526 memcpy(&s
->next_codebook_buffer
[s
->next_codebook_buffer_index
],
527 &s
->buf
[cbp0_chunk
], chunk_size
);
528 s
->next_codebook_buffer_index
+= chunk_size
;
530 s
->partial_countdown
--;
531 if (s
->partial_countdown
== 0) {
533 /* time to replace codebook */
534 memcpy(s
->codebook
, s
->next_codebook_buffer
,
535 s
->next_codebook_buffer_index
);
537 /* reset accounting */
538 s
->next_codebook_buffer_index
= 0;
539 s
->partial_countdown
= s
->partial_count
;
543 if (cbpz_chunk
!= -1) {
545 chunk_size
= AV_RB32(&s
->buf
[cbpz_chunk
+ 4]);
546 cbpz_chunk
+= CHUNK_PREAMBLE_SIZE
;
548 /* accumulate partial codebook */
549 memcpy(&s
->next_codebook_buffer
[s
->next_codebook_buffer_index
],
550 &s
->buf
[cbpz_chunk
], chunk_size
);
551 s
->next_codebook_buffer_index
+= chunk_size
;
553 s
->partial_countdown
--;
554 if (s
->partial_countdown
== 0) {
556 /* decompress codebook */
557 decode_format80(s
->next_codebook_buffer
,
558 s
->next_codebook_buffer_index
,
559 s
->codebook
, s
->codebook_size
, 0);
561 /* reset accounting */
562 s
->next_codebook_buffer_index
= 0;
563 s
->partial_countdown
= s
->partial_count
;
568 static int vqa_decode_frame(AVCodecContext
*avctx
,
569 void *data
, int *data_size
,
570 uint8_t *buf
, int buf_size
)
572 VqaContext
*s
= avctx
->priv_data
;
577 if (s
->frame
.data
[0])
578 avctx
->release_buffer(avctx
, &s
->frame
);
580 if (avctx
->get_buffer(avctx
, &s
->frame
)) {
581 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA Video: get_buffer() failed\n");
587 /* make the palette available on the way out */
588 memcpy(s
->frame
.data
[1], s
->palette
, PALETTE_COUNT
* 4);
589 s
->frame
.palette_has_changed
= 1;
591 *data_size
= sizeof(AVFrame
);
592 *(AVFrame
*)data
= s
->frame
;
594 /* report that the buffer was completely consumed */
598 static int vqa_decode_end(AVCodecContext
*avctx
)
600 VqaContext
*s
= avctx
->priv_data
;
602 av_free(s
->codebook
);
603 av_free(s
->next_codebook_buffer
);
604 av_free(s
->decode_buffer
);
606 if (s
->frame
.data
[0])
607 avctx
->release_buffer(avctx
, &s
->frame
);
612 AVCodec vqa_decoder
= {