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
73 #define PALETTE_COUNT 256
74 #define VQA_HEADER_SIZE 0x2A
75 #define CHUNK_PREAMBLE_SIZE 8
77 /* allocate the maximum vector space, regardless of the file version:
78 * (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
79 #define MAX_CODEBOOK_VECTORS 0xFF00
80 #define SOLID_PIXEL_VECTORS 0x100
81 #define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
82 #define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)
84 #define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
85 #define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
86 #define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
87 #define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
88 #define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
89 #define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
90 #define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')
95 #define vqa_debug printf
97 static inline void vqa_debug(const char *format
, ...) { }
100 typedef struct VqaContext
{
102 AVCodecContext
*avctx
;
105 const unsigned char *buf
;
108 uint32_t palette
[PALETTE_COUNT
];
110 int width
; /* width of a frame */
111 int height
; /* height of a frame */
112 int vector_width
; /* width of individual vector */
113 int vector_height
; /* height of individual vector */
114 int vqa_version
; /* this should be either 1, 2 or 3 */
116 unsigned char *codebook
; /* the current codebook */
118 unsigned char *next_codebook_buffer
; /* accumulator for next codebook */
119 int next_codebook_buffer_index
;
121 unsigned char *decode_buffer
;
122 int decode_buffer_size
;
124 /* number of frames to go before replacing codebook */
125 int partial_countdown
;
130 static av_cold
int vqa_decode_init(AVCodecContext
*avctx
)
132 VqaContext
*s
= avctx
->priv_data
;
133 unsigned char *vqa_header
;
134 int i
, j
, codebook_index
;
137 avctx
->pix_fmt
= PIX_FMT_PAL8
;
139 /* make sure the extradata made it */
140 if (s
->avctx
->extradata_size
!= VQA_HEADER_SIZE
) {
141 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE
);
145 /* load up the VQA parameters from the header */
146 vqa_header
= (unsigned char *)s
->avctx
->extradata
;
147 s
->vqa_version
= vqa_header
[0];
148 s
->width
= AV_RL16(&vqa_header
[6]);
149 s
->height
= AV_RL16(&vqa_header
[8]);
150 if(avcodec_check_dimensions(avctx
, s
->width
, s
->height
)){
151 s
->width
= s
->height
= 0;
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(const 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
= AV_RL16(&src
[src_index
]);
231 src_pos
= AV_RL16(&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
= AV_RL16(&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
= AV_RL16(&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
= AV_RB16(&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
= AV_RB32(&s
->buf
[index
]);
324 chunk_size
= AV_RB32(&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
= AV_RB32(&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
= AV_RB32(&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
= AV_RB32(&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
= AV_RB32(&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) */
468 lobyte
= s
->decode_buffer
[lobytes
* 2];
469 hibyte
= s
->decode_buffer
[(lobytes
* 2) + 1];
470 vector_index
= ((hibyte
<< 8) | lobyte
) >> 3;
471 vector_index
<<= index_shift
;
472 lines
= s
->vector_height
;
473 /* uniform color fill - a quick hack */
474 if (hibyte
== 0xFF) {
476 s
->frame
.data
[0][pixel_ptr
+ 0] = 255 - lobyte
;
477 s
->frame
.data
[0][pixel_ptr
+ 1] = 255 - lobyte
;
478 s
->frame
.data
[0][pixel_ptr
+ 2] = 255 - lobyte
;
479 s
->frame
.data
[0][pixel_ptr
+ 3] = 255 - lobyte
;
480 pixel_ptr
+= s
->frame
.linesize
[0];
487 lobyte
= s
->decode_buffer
[lobytes
];
488 hibyte
= s
->decode_buffer
[hibytes
];
489 vector_index
= (hibyte
<< 8) | lobyte
;
490 vector_index
<<= index_shift
;
491 lines
= s
->vector_height
;
495 /* not implemented yet */
501 s
->frame
.data
[0][pixel_ptr
+ 0] = s
->codebook
[vector_index
++];
502 s
->frame
.data
[0][pixel_ptr
+ 1] = s
->codebook
[vector_index
++];
503 s
->frame
.data
[0][pixel_ptr
+ 2] = s
->codebook
[vector_index
++];
504 s
->frame
.data
[0][pixel_ptr
+ 3] = s
->codebook
[vector_index
++];
505 pixel_ptr
+= s
->frame
.linesize
[0];
510 /* handle partial codebook */
511 if ((cbp0_chunk
!= -1) && (cbpz_chunk
!= -1)) {
512 /* a chunk should not have both chunk types */
513 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
517 if (cbp0_chunk
!= -1) {
519 chunk_size
= AV_RB32(&s
->buf
[cbp0_chunk
+ 4]);
520 cbp0_chunk
+= CHUNK_PREAMBLE_SIZE
;
522 /* accumulate partial codebook */
523 memcpy(&s
->next_codebook_buffer
[s
->next_codebook_buffer_index
],
524 &s
->buf
[cbp0_chunk
], chunk_size
);
525 s
->next_codebook_buffer_index
+= chunk_size
;
527 s
->partial_countdown
--;
528 if (s
->partial_countdown
== 0) {
530 /* time to replace codebook */
531 memcpy(s
->codebook
, s
->next_codebook_buffer
,
532 s
->next_codebook_buffer_index
);
534 /* reset accounting */
535 s
->next_codebook_buffer_index
= 0;
536 s
->partial_countdown
= s
->partial_count
;
540 if (cbpz_chunk
!= -1) {
542 chunk_size
= AV_RB32(&s
->buf
[cbpz_chunk
+ 4]);
543 cbpz_chunk
+= CHUNK_PREAMBLE_SIZE
;
545 /* accumulate partial codebook */
546 memcpy(&s
->next_codebook_buffer
[s
->next_codebook_buffer_index
],
547 &s
->buf
[cbpz_chunk
], chunk_size
);
548 s
->next_codebook_buffer_index
+= chunk_size
;
550 s
->partial_countdown
--;
551 if (s
->partial_countdown
== 0) {
553 /* decompress codebook */
554 decode_format80(s
->next_codebook_buffer
,
555 s
->next_codebook_buffer_index
,
556 s
->codebook
, s
->codebook_size
, 0);
558 /* reset accounting */
559 s
->next_codebook_buffer_index
= 0;
560 s
->partial_countdown
= s
->partial_count
;
565 static int vqa_decode_frame(AVCodecContext
*avctx
,
566 void *data
, int *data_size
,
567 const uint8_t *buf
, int buf_size
)
569 VqaContext
*s
= avctx
->priv_data
;
574 if (s
->frame
.data
[0])
575 avctx
->release_buffer(avctx
, &s
->frame
);
577 if (avctx
->get_buffer(avctx
, &s
->frame
)) {
578 av_log(s
->avctx
, AV_LOG_ERROR
, " VQA Video: get_buffer() failed\n");
584 /* make the palette available on the way out */
585 memcpy(s
->frame
.data
[1], s
->palette
, PALETTE_COUNT
* 4);
586 s
->frame
.palette_has_changed
= 1;
588 *data_size
= sizeof(AVFrame
);
589 *(AVFrame
*)data
= s
->frame
;
591 /* report that the buffer was completely consumed */
595 static av_cold
int vqa_decode_end(AVCodecContext
*avctx
)
597 VqaContext
*s
= avctx
->priv_data
;
599 av_free(s
->codebook
);
600 av_free(s
->next_codebook_buffer
);
601 av_free(s
->decode_buffer
);
603 if (s
->frame
.data
[0])
604 avctx
->release_buffer(avctx
, &s
->frame
);
609 AVCodec vqa_decoder
= {
619 .long_name
= "Westwood Studios VQA (Vector Quantized Animation) video",