2 * Westwood Studios VQA Video Decoder
3 * Copyright (C) 2003 the ffmpeg project
5 * This file is part of Libav.
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * @author Mike Melanson (melanson@pcisys.net)
26 * @see 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"
73 #include "bytestream.h"
75 #define PALETTE_COUNT 256
76 #define VQA_HEADER_SIZE 0x2A
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;
99 uint32_t palette[PALETTE_COUNT];
101 int width; /* width of a frame */
102 int height; /* height of a frame */
103 int vector_width; /* width of individual vector */
104 int vector_height; /* height of individual vector */
105 int vqa_version; /* this should be either 1, 2 or 3 */
107 unsigned char *codebook; /* the current codebook */
109 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
110 int next_codebook_buffer_index;
112 unsigned char *decode_buffer;
113 int decode_buffer_size;
115 /* number of frames to go before replacing codebook */
116 int partial_countdown;
121 static av_cold int vqa_decode_init(AVCodecContext *avctx)
123 VqaContext *s = avctx->priv_data;
124 int i, j, codebook_index;
127 avctx->pix_fmt = AV_PIX_FMT_PAL8;
129 /* make sure the extradata made it */
130 if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
131 av_log(s->avctx, AV_LOG_ERROR, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);
135 /* load up the VQA parameters from the header */
136 s->vqa_version = s->avctx->extradata[0];
137 s->width = AV_RL16(&s->avctx->extradata[6]);
138 s->height = AV_RL16(&s->avctx->extradata[8]);
139 if(av_image_check_size(s->width, s->height, 0, avctx)){
140 s->width= s->height= 0;
143 s->vector_width = s->avctx->extradata[10];
144 s->vector_height = s->avctx->extradata[11];
145 s->partial_count = s->partial_countdown = s->avctx->extradata[13];
147 /* the vector dimensions have to meet very stringent requirements */
148 if ((s->vector_width != 4) ||
149 ((s->vector_height != 2) && (s->vector_height != 4))) {
150 /* return without further initialization */
154 if (s->width & (s->vector_width - 1) ||
155 s->height & (s->vector_height - 1)) {
156 av_log(avctx, AV_LOG_ERROR, "Image size not multiple of block size\n");
157 return AVERROR_INVALIDDATA;
160 /* allocate codebooks */
161 s->codebook_size = MAX_CODEBOOK_SIZE;
162 s->codebook = av_malloc(s->codebook_size);
165 s->next_codebook_buffer = av_malloc(s->codebook_size);
166 if (!s->next_codebook_buffer)
169 /* allocate decode buffer */
170 s->decode_buffer_size = (s->width / s->vector_width) *
171 (s->height / s->vector_height) * 2;
172 s->decode_buffer = av_malloc(s->decode_buffer_size);
173 if (!s->decode_buffer)
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 s->frame.data[0] = NULL;
194 av_freep(&s->codebook);
195 av_freep(&s->next_codebook_buffer);
196 av_freep(&s->decode_buffer);
197 return AVERROR(ENOMEM);
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); \
205 return AVERROR_INVALIDDATA; \
208 #define CHECK_COPY(idx) \
209 if (idx < 0 || idx + count > dest_size) { \
210 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
211 av_log(NULL, AV_LOG_ERROR, " VQA video: current src_pos = %d, count = %d, dest_size = %d\n", \
212 src_pos, count, dest_size); \
213 return AVERROR_INVALIDDATA; \
217 static int decode_format80(GetByteContext *gb, int src_size,
218 unsigned char *dest, int dest_size, int check_size) {
221 int count, opcode, start;
226 start = bytestream2_tell(gb);
227 while (bytestream2_tell(gb) - start < src_size) {
228 opcode = bytestream2_get_byte(gb);
229 av_dlog(NULL, " opcode %02X: ", opcode);
231 /* 0x80 means that frame is finished */
235 if (dest_index >= dest_size) {
236 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
237 dest_index, dest_size);
238 return AVERROR_INVALIDDATA;
241 if (opcode == 0xFF) {
243 count = bytestream2_get_le16(gb);
244 src_pos = bytestream2_get_le16(gb);
245 av_dlog(NULL, "(1) copy %X bytes from absolute pos %X\n", count, src_pos);
248 for (i = 0; i < count; i++)
249 dest[dest_index + i] = dest[src_pos + i];
252 } else if (opcode == 0xFE) {
254 count = bytestream2_get_le16(gb);
255 color = bytestream2_get_byte(gb);
256 av_dlog(NULL, "(2) set %X bytes to %02X\n", count, color);
258 memset(&dest[dest_index], color, count);
261 } else if ((opcode & 0xC0) == 0xC0) {
263 count = (opcode & 0x3F) + 3;
264 src_pos = bytestream2_get_le16(gb);
265 av_dlog(NULL, "(3) copy %X bytes from absolute pos %X\n", count, src_pos);
268 for (i = 0; i < count; i++)
269 dest[dest_index + i] = dest[src_pos + i];
272 } else if (opcode > 0x80) {
274 count = opcode & 0x3F;
275 av_dlog(NULL, "(4) copy %X bytes from source to dest\n", count);
277 bytestream2_get_buffer(gb, &dest[dest_index], count);
282 count = ((opcode & 0x70) >> 4) + 3;
283 src_pos = bytestream2_get_byte(gb) | ((opcode & 0x0F) << 8);
284 av_dlog(NULL, "(5) copy %X bytes from relpos %X\n", count, src_pos);
286 CHECK_COPY(dest_index - src_pos);
287 for (i = 0; i < count; i++)
288 dest[dest_index + i] = dest[dest_index - src_pos + i];
293 /* validate that the entire destination buffer was filled; this is
294 * important for decoding frame maps since each vector needs to have a
295 * codebook entry; it is not important for compressed codebooks because
296 * not every entry needs to be filled */
298 if (dest_index < dest_size)
299 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
300 dest_index, dest_size);
302 return 0; // let's display what we decoded anyway
305 static int vqa_decode_chunk(VqaContext *s)
307 unsigned int chunk_type;
308 unsigned int chunk_size;
310 unsigned int index = 0;
312 unsigned char r, g, b;
327 int vector_index = 0;
331 int hibytes = s->decode_buffer_size / 2;
333 /* first, traverse through the frame and find the subchunks */
334 while (bytestream2_get_bytes_left(&s->gb) >= 8) {
336 chunk_type = bytestream2_get_be32u(&s->gb);
337 index = bytestream2_tell(&s->gb);
338 chunk_size = bytestream2_get_be32u(&s->gb);
340 switch (chunk_type) {
371 av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
372 (chunk_type >> 24) & 0xFF,
373 (chunk_type >> 16) & 0xFF,
374 (chunk_type >> 8) & 0xFF,
375 (chunk_type >> 0) & 0xFF,
380 byte_skip = chunk_size & 0x01;
381 bytestream2_skip(&s->gb, chunk_size + byte_skip);
384 /* next, deal with the palette */
385 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
387 /* a chunk should not have both chunk types */
388 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
389 return AVERROR_INVALIDDATA;
392 /* decompress the palette chunk */
393 if (cplz_chunk != -1) {
395 /* yet to be handled */
399 /* convert the RGB palette into the machine's endian format */
400 if (cpl0_chunk != -1) {
402 bytestream2_seek(&s->gb, cpl0_chunk, SEEK_SET);
403 chunk_size = bytestream2_get_be32(&s->gb);
404 /* sanity check the palette size */
405 if (chunk_size / 3 > 256 || chunk_size > bytestream2_get_bytes_left(&s->gb)) {
406 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
408 return AVERROR_INVALIDDATA;
410 for (i = 0; i < chunk_size / 3; i++) {
411 /* scale by 4 to transform 6-bit palette -> 8-bit */
412 r = bytestream2_get_byteu(&s->gb) * 4;
413 g = bytestream2_get_byteu(&s->gb) * 4;
414 b = bytestream2_get_byteu(&s->gb) * 4;
415 s->palette[i] = (r << 16) | (g << 8) | (b);
419 /* next, look for a full codebook */
420 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
422 /* a chunk should not have both chunk types */
423 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
424 return AVERROR_INVALIDDATA;
427 /* decompress the full codebook chunk */
428 if (cbfz_chunk != -1) {
430 bytestream2_seek(&s->gb, cbfz_chunk, SEEK_SET);
431 chunk_size = bytestream2_get_be32(&s->gb);
432 if ((res = decode_format80(&s->gb, chunk_size, s->codebook,
433 s->codebook_size, 0)) < 0)
437 /* copy a full codebook */
438 if (cbf0_chunk != -1) {
440 bytestream2_seek(&s->gb, cbf0_chunk, SEEK_SET);
441 chunk_size = bytestream2_get_be32(&s->gb);
442 /* sanity check the full codebook size */
443 if (chunk_size > MAX_CODEBOOK_SIZE) {
444 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
446 return AVERROR_INVALIDDATA;
449 bytestream2_get_buffer(&s->gb, s->codebook, chunk_size);
452 /* decode the frame */
453 if (vptz_chunk == -1) {
455 /* something is wrong if there is no VPTZ chunk */
456 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
457 return AVERROR_INVALIDDATA;
460 bytestream2_seek(&s->gb, vptz_chunk, SEEK_SET);
461 chunk_size = bytestream2_get_be32(&s->gb);
462 if ((res = decode_format80(&s->gb, chunk_size,
463 s->decode_buffer, s->decode_buffer_size, 1)) < 0)
466 /* render the final PAL8 frame */
467 if (s->vector_height == 4)
471 for (y = 0; y < s->height; y += s->vector_height) {
472 for (x = 0; x < s->width; x += 4, lobytes++, hibytes++) {
473 pixel_ptr = y * s->frame.linesize[0] + x;
475 /* get the vector index, the method for which varies according to
476 * VQA file version */
477 switch (s->vqa_version) {
480 lobyte = s->decode_buffer[lobytes * 2];
481 hibyte = s->decode_buffer[(lobytes * 2) + 1];
482 vector_index = ((hibyte << 8) | lobyte) >> 3;
483 vector_index <<= index_shift;
484 lines = s->vector_height;
485 /* uniform color fill - a quick hack */
486 if (hibyte == 0xFF) {
488 s->frame.data[0][pixel_ptr + 0] = 255 - lobyte;
489 s->frame.data[0][pixel_ptr + 1] = 255 - lobyte;
490 s->frame.data[0][pixel_ptr + 2] = 255 - lobyte;
491 s->frame.data[0][pixel_ptr + 3] = 255 - lobyte;
492 pixel_ptr += s->frame.linesize[0];
499 lobyte = s->decode_buffer[lobytes];
500 hibyte = s->decode_buffer[hibytes];
501 vector_index = (hibyte << 8) | lobyte;
502 vector_index <<= index_shift;
503 lines = s->vector_height;
507 /* not implemented yet */
513 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
514 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
515 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
516 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
517 pixel_ptr += s->frame.linesize[0];
522 /* handle partial codebook */
523 if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
524 /* a chunk should not have both chunk types */
525 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBP0 and CBPZ chunks\n");
526 return AVERROR_INVALIDDATA;
529 if (cbp0_chunk != -1) {
531 bytestream2_seek(&s->gb, cbp0_chunk, SEEK_SET);
532 chunk_size = bytestream2_get_be32(&s->gb);
534 /* accumulate partial codebook */
535 bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
537 s->next_codebook_buffer_index += chunk_size;
539 s->partial_countdown--;
540 if (s->partial_countdown == 0) {
542 /* time to replace codebook */
543 memcpy(s->codebook, s->next_codebook_buffer,
544 s->next_codebook_buffer_index);
546 /* reset accounting */
547 s->next_codebook_buffer_index = 0;
548 s->partial_countdown = s->partial_count;
552 if (cbpz_chunk != -1) {
554 bytestream2_seek(&s->gb, cbpz_chunk, SEEK_SET);
555 chunk_size = bytestream2_get_be32(&s->gb);
557 /* accumulate partial codebook */
558 bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
560 s->next_codebook_buffer_index += chunk_size;
562 s->partial_countdown--;
563 if (s->partial_countdown == 0) {
566 bytestream2_init(&gb, s->next_codebook_buffer, s->next_codebook_buffer_index);
567 /* decompress codebook */
568 if ((res = decode_format80(&gb, s->next_codebook_buffer_index,
569 s->codebook, s->codebook_size, 0)) < 0)
572 /* reset accounting */
573 s->next_codebook_buffer_index = 0;
574 s->partial_countdown = s->partial_count;
581 static int vqa_decode_frame(AVCodecContext *avctx,
582 void *data, int *data_size,
585 VqaContext *s = avctx->priv_data;
588 if (s->frame.data[0])
589 avctx->release_buffer(avctx, &s->frame);
591 if (avctx->get_buffer(avctx, &s->frame)) {
592 av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
596 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
597 if ((res = vqa_decode_chunk(s)) < 0)
600 /* make the palette available on the way out */
601 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
602 s->frame.palette_has_changed = 1;
604 *data_size = sizeof(AVFrame);
605 *(AVFrame*)data = s->frame;
607 /* report that the buffer was completely consumed */
611 static av_cold int vqa_decode_end(AVCodecContext *avctx)
613 VqaContext *s = avctx->priv_data;
615 av_freep(&s->codebook);
616 av_freep(&s->next_codebook_buffer);
617 av_freep(&s->decode_buffer);
619 if (s->frame.data[0])
620 avctx->release_buffer(avctx, &s->frame);
625 AVCodec ff_vqa_decoder = {
627 .type = AVMEDIA_TYPE_VIDEO,
628 .id = AV_CODEC_ID_WS_VQA,
629 .priv_data_size = sizeof(VqaContext),
630 .init = vqa_decode_init,
631 .close = vqa_decode_end,
632 .decode = vqa_decode_frame,
633 .capabilities = CODEC_CAP_DR1,
634 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios VQA (Vector Quantized Animation) video"),