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 indexes. If the 12-bit indexes 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
70 #include "libavutil/intreadwrite.h"
71 #include "libavutil/imgutils.h"
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')
93 typedef struct VqaContext {
95 AVCodecContext *avctx;
98 const unsigned char *buf;
101 uint32_t palette[PALETTE_COUNT];
103 int width; /* width of a frame */
104 int height; /* height of a frame */
105 int vector_width; /* width of individual vector */
106 int vector_height; /* height of individual vector */
107 int vqa_version; /* this should be either 1, 2 or 3 */
109 unsigned char *codebook; /* the current codebook */
111 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
112 int next_codebook_buffer_index;
114 unsigned char *decode_buffer;
115 int decode_buffer_size;
117 /* number of frames to go before replacing codebook */
118 int partial_countdown;
123 static av_cold int vqa_decode_init(AVCodecContext *avctx)
125 VqaContext *s = avctx->priv_data;
126 unsigned char *vqa_header;
127 int i, j, codebook_index;
130 avctx->pix_fmt = PIX_FMT_PAL8;
132 /* make sure the extradata made it */
133 if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
134 av_log(s->avctx, AV_LOG_ERROR, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);
138 /* load up the VQA parameters from the header */
139 vqa_header = (unsigned char *)s->avctx->extradata;
140 s->vqa_version = vqa_header[0];
141 s->width = AV_RL16(&vqa_header[6]);
142 s->height = AV_RL16(&vqa_header[8]);
143 if(av_image_check_size(s->width, s->height, 0, avctx)){
144 s->width= s->height= 0;
147 s->vector_width = vqa_header[10];
148 s->vector_height = vqa_header[11];
149 s->partial_count = s->partial_countdown = vqa_header[13];
151 /* the vector dimensions have to meet very stringent requirements */
152 if ((s->vector_width != 4) ||
153 ((s->vector_height != 2) && (s->vector_height != 4))) {
154 /* return without further initialization */
158 /* allocate codebooks */
159 s->codebook_size = MAX_CODEBOOK_SIZE;
160 s->codebook = av_malloc(s->codebook_size);
161 s->next_codebook_buffer = av_malloc(s->codebook_size);
163 /* initialize the solid-color vectors */
164 if (s->vector_height == 4) {
165 codebook_index = 0xFF00 * 16;
166 for (i = 0; i < 256; i++)
167 for (j = 0; j < 16; j++)
168 s->codebook[codebook_index++] = i;
170 codebook_index = 0xF00 * 8;
171 for (i = 0; i < 256; i++)
172 for (j = 0; j < 8; j++)
173 s->codebook[codebook_index++] = i;
175 s->next_codebook_buffer_index = 0;
177 /* allocate decode buffer */
178 s->decode_buffer_size = (s->width / s->vector_width) *
179 (s->height / s->vector_height) * 2;
180 s->decode_buffer = av_malloc(s->decode_buffer_size);
182 avcodec_get_frame_defaults(&s->frame);
183 s->frame.data[0] = NULL;
188 #define CHECK_COUNT() \
189 if (dest_index + count > dest_size) { \
190 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
191 av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
192 dest_index, count, dest_size); \
196 static void decode_format80(const unsigned char *src, int src_size,
197 unsigned char *dest, int dest_size, int check_size) {
206 while (src_index < src_size) {
208 av_dlog(NULL, " opcode %02X: ", src[src_index]);
210 /* 0x80 means that frame is finished */
211 if (src[src_index] == 0x80)
214 if (dest_index >= dest_size) {
215 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
216 dest_index, dest_size);
220 if (src[src_index] == 0xFF) {
223 count = AV_RL16(&src[src_index]);
225 src_pos = AV_RL16(&src[src_index]);
227 av_dlog(NULL, "(1) copy %X bytes from absolute pos %X\n", count, src_pos);
229 for (i = 0; i < count; i++)
230 dest[dest_index + i] = dest[src_pos + i];
233 } else if (src[src_index] == 0xFE) {
236 count = AV_RL16(&src[src_index]);
238 color = src[src_index++];
239 av_dlog(NULL, "(2) set %X bytes to %02X\n", count, color);
241 memset(&dest[dest_index], color, count);
244 } else if ((src[src_index] & 0xC0) == 0xC0) {
246 count = (src[src_index++] & 0x3F) + 3;
247 src_pos = AV_RL16(&src[src_index]);
249 av_dlog(NULL, "(3) copy %X bytes from absolute pos %X\n", count, src_pos);
251 for (i = 0; i < count; i++)
252 dest[dest_index + i] = dest[src_pos + i];
255 } else if (src[src_index] > 0x80) {
257 count = src[src_index++] & 0x3F;
258 av_dlog(NULL, "(4) copy %X bytes from source to dest\n", count);
260 memcpy(&dest[dest_index], &src[src_index], count);
266 count = ((src[src_index] & 0x70) >> 4) + 3;
267 src_pos = AV_RB16(&src[src_index]) & 0x0FFF;
269 av_dlog(NULL, "(5) copy %X bytes from relpos %X\n", count, src_pos);
271 for (i = 0; i < count; i++)
272 dest[dest_index + i] = dest[dest_index - src_pos + i];
277 /* validate that the entire destination buffer was filled; this is
278 * important for decoding frame maps since each vector needs to have a
279 * codebook entry; it is not important for compressed codebooks because
280 * not every entry needs to be filled */
282 if (dest_index < dest_size)
283 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
284 dest_index, dest_size);
287 static void vqa_decode_chunk(VqaContext *s)
289 unsigned int chunk_type;
290 unsigned int chunk_size;
292 unsigned int index = 0;
294 unsigned char r, g, b;
308 int vector_index = 0;
312 int hibytes = s->decode_buffer_size / 2;
314 /* first, traverse through the frame and find the subchunks */
315 while (index < s->size) {
317 chunk_type = AV_RB32(&s->buf[index]);
318 chunk_size = AV_RB32(&s->buf[index + 4]);
320 switch (chunk_type) {
351 av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
352 (chunk_type >> 24) & 0xFF,
353 (chunk_type >> 16) & 0xFF,
354 (chunk_type >> 8) & 0xFF,
355 (chunk_type >> 0) & 0xFF,
360 byte_skip = chunk_size & 0x01;
361 index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
364 /* next, deal with the palette */
365 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
367 /* a chunk should not have both chunk types */
368 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
372 /* decompress the palette chunk */
373 if (cplz_chunk != -1) {
375 /* yet to be handled */
379 /* convert the RGB palette into the machine's endian format */
380 if (cpl0_chunk != -1) {
382 chunk_size = AV_RB32(&s->buf[cpl0_chunk + 4]);
383 /* sanity check the palette size */
384 if (chunk_size / 3 > 256) {
385 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
389 cpl0_chunk += CHUNK_PREAMBLE_SIZE;
390 for (i = 0; i < chunk_size / 3; i++) {
391 /* scale by 4 to transform 6-bit palette -> 8-bit */
392 r = s->buf[cpl0_chunk++] * 4;
393 g = s->buf[cpl0_chunk++] * 4;
394 b = s->buf[cpl0_chunk++] * 4;
395 s->palette[i] = (r << 16) | (g << 8) | (b);
399 /* next, look for a full codebook */
400 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
402 /* a chunk should not have both chunk types */
403 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
407 /* decompress the full codebook chunk */
408 if (cbfz_chunk != -1) {
410 chunk_size = AV_RB32(&s->buf[cbfz_chunk + 4]);
411 cbfz_chunk += CHUNK_PREAMBLE_SIZE;
412 decode_format80(&s->buf[cbfz_chunk], chunk_size,
413 s->codebook, s->codebook_size, 0);
416 /* copy a full codebook */
417 if (cbf0_chunk != -1) {
419 chunk_size = AV_RB32(&s->buf[cbf0_chunk + 4]);
420 /* sanity check the full codebook size */
421 if (chunk_size > MAX_CODEBOOK_SIZE) {
422 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
426 cbf0_chunk += CHUNK_PREAMBLE_SIZE;
428 memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
431 /* decode the frame */
432 if (vptz_chunk == -1) {
434 /* something is wrong if there is no VPTZ chunk */
435 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
439 chunk_size = AV_RB32(&s->buf[vptz_chunk + 4]);
440 vptz_chunk += CHUNK_PREAMBLE_SIZE;
441 decode_format80(&s->buf[vptz_chunk], chunk_size,
442 s->decode_buffer, s->decode_buffer_size, 1);
444 /* render the final PAL8 frame */
445 if (s->vector_height == 4)
449 for (y = 0; y < s->frame.linesize[0] * s->height;
450 y += s->frame.linesize[0] * s->vector_height) {
452 for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
455 /* get the vector index, the method for which varies according to
456 * VQA file version */
457 switch (s->vqa_version) {
460 lobyte = s->decode_buffer[lobytes * 2];
461 hibyte = s->decode_buffer[(lobytes * 2) + 1];
462 vector_index = ((hibyte << 8) | lobyte) >> 3;
463 vector_index <<= index_shift;
464 lines = s->vector_height;
465 /* uniform color fill - a quick hack */
466 if (hibyte == 0xFF) {
468 s->frame.data[0][pixel_ptr + 0] = 255 - lobyte;
469 s->frame.data[0][pixel_ptr + 1] = 255 - lobyte;
470 s->frame.data[0][pixel_ptr + 2] = 255 - lobyte;
471 s->frame.data[0][pixel_ptr + 3] = 255 - lobyte;
472 pixel_ptr += s->frame.linesize[0];
479 lobyte = s->decode_buffer[lobytes];
480 hibyte = s->decode_buffer[hibytes];
481 vector_index = (hibyte << 8) | lobyte;
482 vector_index <<= index_shift;
483 lines = s->vector_height;
487 /* not implemented yet */
493 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
494 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
495 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
496 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
497 pixel_ptr += s->frame.linesize[0];
502 /* handle partial codebook */
503 if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
504 /* a chunk should not have both chunk types */
505 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
509 if (cbp0_chunk != -1) {
511 chunk_size = AV_RB32(&s->buf[cbp0_chunk + 4]);
512 cbp0_chunk += CHUNK_PREAMBLE_SIZE;
514 /* accumulate partial codebook */
515 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
516 &s->buf[cbp0_chunk], chunk_size);
517 s->next_codebook_buffer_index += chunk_size;
519 s->partial_countdown--;
520 if (s->partial_countdown == 0) {
522 /* time to replace codebook */
523 memcpy(s->codebook, s->next_codebook_buffer,
524 s->next_codebook_buffer_index);
526 /* reset accounting */
527 s->next_codebook_buffer_index = 0;
528 s->partial_countdown = s->partial_count;
532 if (cbpz_chunk != -1) {
534 chunk_size = AV_RB32(&s->buf[cbpz_chunk + 4]);
535 cbpz_chunk += CHUNK_PREAMBLE_SIZE;
537 /* accumulate partial codebook */
538 memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
539 &s->buf[cbpz_chunk], chunk_size);
540 s->next_codebook_buffer_index += chunk_size;
542 s->partial_countdown--;
543 if (s->partial_countdown == 0) {
545 /* decompress codebook */
546 decode_format80(s->next_codebook_buffer,
547 s->next_codebook_buffer_index,
548 s->codebook, s->codebook_size, 0);
550 /* reset accounting */
551 s->next_codebook_buffer_index = 0;
552 s->partial_countdown = s->partial_count;
557 static int vqa_decode_frame(AVCodecContext *avctx,
558 void *data, int *data_size,
561 const uint8_t *buf = avpkt->data;
562 int buf_size = avpkt->size;
563 VqaContext *s = avctx->priv_data;
568 if (s->frame.data[0])
569 avctx->release_buffer(avctx, &s->frame);
571 if (avctx->get_buffer(avctx, &s->frame)) {
572 av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
578 /* make the palette available on the way out */
579 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
580 s->frame.palette_has_changed = 1;
582 *data_size = sizeof(AVFrame);
583 *(AVFrame*)data = s->frame;
585 /* report that the buffer was completely consumed */
589 static av_cold int vqa_decode_end(AVCodecContext *avctx)
591 VqaContext *s = avctx->priv_data;
593 av_free(s->codebook);
594 av_free(s->next_codebook_buffer);
595 av_free(s->decode_buffer);
597 if (s->frame.data[0])
598 avctx->release_buffer(avctx, &s->frame);
603 AVCodec ff_vqa_decoder = {
613 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios VQA (Vector Quantized Animation) video"),