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
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"
76 #define PALETTE_COUNT 256
77 #define VQA_HEADER_SIZE 0x2A
79 /* allocate the maximum vector space, regardless of the file version:
80 * (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
81 #define MAX_CODEBOOK_VECTORS 0xFF00
82 #define SOLID_PIXEL_VECTORS 0x100
83 #define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
84 #define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)
86 #define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
87 #define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
88 #define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
89 #define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
90 #define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
91 #define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
92 #define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')
94 typedef struct VqaContext {
96 AVCodecContext *avctx;
100 uint32_t palette[PALETTE_COUNT];
102 int width; /* width of a frame */
103 int height; /* height of a frame */
104 int vector_width; /* width of individual vector */
105 int vector_height; /* height of individual vector */
106 int vqa_version; /* this should be either 1, 2 or 3 */
108 unsigned char *codebook; /* the current codebook */
110 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
111 int next_codebook_buffer_index;
113 unsigned char *decode_buffer;
114 int decode_buffer_size;
116 /* number of frames to go before replacing codebook */
117 int partial_countdown;
122 static av_cold int vqa_decode_init(AVCodecContext *avctx)
124 VqaContext *s = avctx->priv_data;
125 int i, j, codebook_index, ret;
128 avctx->pix_fmt = AV_PIX_FMT_PAL8;
130 /* make sure the extradata made it */
131 if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
132 av_log(s->avctx, AV_LOG_ERROR, "expected extradata size of %d\n", VQA_HEADER_SIZE);
133 return AVERROR(EINVAL);
136 /* load up the VQA parameters from the header */
137 s->vqa_version = s->avctx->extradata[0];
138 if (s->vqa_version < 1 || s->vqa_version > 3) {
139 av_log(s->avctx, AV_LOG_ERROR, "unsupported version %d\n", s->vqa_version);
140 return AVERROR_PATCHWELCOME;
142 s->width = AV_RL16(&s->avctx->extradata[6]);
143 s->height = AV_RL16(&s->avctx->extradata[8]);
144 if ((ret = av_image_check_size(s->width, s->height, 0, avctx)) < 0) {
145 s->width= s->height= 0;
148 s->vector_width = s->avctx->extradata[10];
149 s->vector_height = s->avctx->extradata[11];
150 s->partial_count = s->partial_countdown = s->avctx->extradata[13];
152 /* the vector dimensions have to meet very stringent requirements */
153 if ((s->vector_width != 4) ||
154 ((s->vector_height != 2) && (s->vector_height != 4))) {
155 /* return without further initialization */
156 return AVERROR_INVALIDDATA;
159 if (s->width % s->vector_width || s->height % s->vector_height) {
160 av_log(avctx, AV_LOG_ERROR, "Image size not multiple of block size\n");
161 return AVERROR_INVALIDDATA;
164 /* allocate codebooks */
165 s->codebook_size = MAX_CODEBOOK_SIZE;
166 s->codebook = av_malloc(s->codebook_size);
169 s->next_codebook_buffer = av_malloc(s->codebook_size);
170 if (!s->next_codebook_buffer)
173 /* allocate decode buffer */
174 s->decode_buffer_size = (s->width / s->vector_width) *
175 (s->height / s->vector_height) * 2;
176 s->decode_buffer = av_malloc(s->decode_buffer_size);
177 if (!s->decode_buffer)
180 /* initialize the solid-color vectors */
181 if (s->vector_height == 4) {
182 codebook_index = 0xFF00 * 16;
183 for (i = 0; i < 256; i++)
184 for (j = 0; j < 16; j++)
185 s->codebook[codebook_index++] = i;
187 codebook_index = 0xF00 * 8;
188 for (i = 0; i < 256; i++)
189 for (j = 0; j < 8; j++)
190 s->codebook[codebook_index++] = i;
192 s->next_codebook_buffer_index = 0;
194 avcodec_get_frame_defaults(&s->frame);
195 s->frame.data[0] = NULL;
199 av_freep(&s->codebook);
200 av_freep(&s->next_codebook_buffer);
201 av_freep(&s->decode_buffer);
202 return AVERROR(ENOMEM);
205 #define CHECK_COUNT() \
206 if (dest_index + count > dest_size) { \
207 av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: next op would overflow dest_index\n"); \
208 av_log(s->avctx, AV_LOG_ERROR, "current dest_index = %d, count = %d, dest_size = %d\n", \
209 dest_index, count, dest_size); \
210 return AVERROR_INVALIDDATA; \
213 #define CHECK_COPY(idx) \
214 if (idx < 0 || idx + count > dest_size) { \
215 av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: next op would overflow dest_index\n"); \
216 av_log(s->avctx, AV_LOG_ERROR, "current src_pos = %d, count = %d, dest_size = %d\n", \
217 src_pos, count, dest_size); \
218 return AVERROR_INVALIDDATA; \
222 static int decode_format80(VqaContext *s, int src_size,
223 unsigned char *dest, int dest_size, int check_size) {
226 int count, opcode, start;
231 start = bytestream2_tell(&s->gb);
232 while (bytestream2_tell(&s->gb) - start < src_size) {
233 opcode = bytestream2_get_byte(&s->gb);
234 av_dlog(s->avctx, "opcode %02X: ", opcode);
236 /* 0x80 means that frame is finished */
240 if (dest_index >= dest_size) {
241 av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
242 dest_index, dest_size);
243 return AVERROR_INVALIDDATA;
246 if (opcode == 0xFF) {
248 count = bytestream2_get_le16(&s->gb);
249 src_pos = bytestream2_get_le16(&s->gb);
250 av_dlog(s->avctx, "(1) copy %X bytes from absolute pos %X\n", count, src_pos);
253 for (i = 0; i < count; i++)
254 dest[dest_index + i] = dest[src_pos + i];
257 } else if (opcode == 0xFE) {
259 count = bytestream2_get_le16(&s->gb);
260 color = bytestream2_get_byte(&s->gb);
261 av_dlog(s->avctx, "(2) set %X bytes to %02X\n", count, color);
263 memset(&dest[dest_index], color, count);
266 } else if ((opcode & 0xC0) == 0xC0) {
268 count = (opcode & 0x3F) + 3;
269 src_pos = bytestream2_get_le16(&s->gb);
270 av_dlog(s->avctx, "(3) copy %X bytes from absolute pos %X\n", count, src_pos);
273 for (i = 0; i < count; i++)
274 dest[dest_index + i] = dest[src_pos + i];
277 } else if (opcode > 0x80) {
279 count = opcode & 0x3F;
280 av_dlog(s->avctx, "(4) copy %X bytes from source to dest\n", count);
282 bytestream2_get_buffer(&s->gb, &dest[dest_index], count);
287 count = ((opcode & 0x70) >> 4) + 3;
288 src_pos = bytestream2_get_byte(&s->gb) | ((opcode & 0x0F) << 8);
289 av_dlog(s->avctx, "(5) copy %X bytes from relpos %X\n", count, src_pos);
291 CHECK_COPY(dest_index - src_pos);
292 for (i = 0; i < count; i++)
293 dest[dest_index + i] = dest[dest_index - src_pos + i];
298 /* validate that the entire destination buffer was filled; this is
299 * important for decoding frame maps since each vector needs to have a
300 * codebook entry; it is not important for compressed codebooks because
301 * not every entry needs to be filled */
303 if (dest_index < dest_size)
304 av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
305 dest_index, dest_size);
307 return 0; // let's display what we decoded anyway
310 static int vqa_decode_chunk(VqaContext *s)
312 unsigned int chunk_type;
313 unsigned int chunk_size;
315 unsigned int index = 0;
317 unsigned char r, g, b;
332 int vector_index = 0;
336 int hibytes = s->decode_buffer_size / 2;
338 /* first, traverse through the frame and find the subchunks */
339 while (bytestream2_get_bytes_left(&s->gb) >= 8) {
341 chunk_type = bytestream2_get_be32u(&s->gb);
342 index = bytestream2_tell(&s->gb);
343 chunk_size = bytestream2_get_be32u(&s->gb);
345 switch (chunk_type) {
376 av_log(s->avctx, AV_LOG_ERROR, "Found unknown chunk type: %c%c%c%c (%08X)\n",
377 (chunk_type >> 24) & 0xFF,
378 (chunk_type >> 16) & 0xFF,
379 (chunk_type >> 8) & 0xFF,
380 (chunk_type >> 0) & 0xFF,
385 byte_skip = chunk_size & 0x01;
386 bytestream2_skip(&s->gb, chunk_size + byte_skip);
389 /* next, deal with the palette */
390 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
392 /* a chunk should not have both chunk types */
393 av_log(s->avctx, AV_LOG_ERROR, "problem: found both CPL0 and CPLZ chunks\n");
394 return AVERROR_INVALIDDATA;
397 /* decompress the palette chunk */
398 if (cplz_chunk != -1) {
400 /* yet to be handled */
404 /* convert the RGB palette into the machine's endian format */
405 if (cpl0_chunk != -1) {
407 bytestream2_seek(&s->gb, cpl0_chunk, SEEK_SET);
408 chunk_size = bytestream2_get_be32(&s->gb);
409 /* sanity check the palette size */
410 if (chunk_size / 3 > 256 || chunk_size > bytestream2_get_bytes_left(&s->gb)) {
411 av_log(s->avctx, AV_LOG_ERROR, "problem: found a palette chunk with %d colors\n",
413 return AVERROR_INVALIDDATA;
415 for (i = 0; i < chunk_size / 3; i++) {
416 /* scale by 4 to transform 6-bit palette -> 8-bit */
417 r = bytestream2_get_byteu(&s->gb) * 4;
418 g = bytestream2_get_byteu(&s->gb) * 4;
419 b = bytestream2_get_byteu(&s->gb) * 4;
420 s->palette[i] = 0xFFU << 24 | r << 16 | g << 8 | b;
421 s->palette[i] |= s->palette[i] >> 6 & 0x30303;
425 /* next, look for a full codebook */
426 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
428 /* a chunk should not have both chunk types */
429 av_log(s->avctx, AV_LOG_ERROR, "problem: found both CBF0 and CBFZ chunks\n");
430 return AVERROR_INVALIDDATA;
433 /* decompress the full codebook chunk */
434 if (cbfz_chunk != -1) {
436 bytestream2_seek(&s->gb, cbfz_chunk, SEEK_SET);
437 chunk_size = bytestream2_get_be32(&s->gb);
438 if ((res = decode_format80(s, chunk_size, s->codebook,
439 s->codebook_size, 0)) < 0)
443 /* copy a full codebook */
444 if (cbf0_chunk != -1) {
446 bytestream2_seek(&s->gb, cbf0_chunk, SEEK_SET);
447 chunk_size = bytestream2_get_be32(&s->gb);
448 /* sanity check the full codebook size */
449 if (chunk_size > MAX_CODEBOOK_SIZE) {
450 av_log(s->avctx, AV_LOG_ERROR, "problem: CBF0 chunk too large (0x%X bytes)\n",
452 return AVERROR_INVALIDDATA;
455 bytestream2_get_buffer(&s->gb, s->codebook, chunk_size);
458 /* decode the frame */
459 if (vptz_chunk == -1) {
461 /* something is wrong if there is no VPTZ chunk */
462 av_log(s->avctx, AV_LOG_ERROR, "problem: no VPTZ chunk found\n");
463 return AVERROR_INVALIDDATA;
466 bytestream2_seek(&s->gb, vptz_chunk, SEEK_SET);
467 chunk_size = bytestream2_get_be32(&s->gb);
468 if ((res = decode_format80(s, chunk_size,
469 s->decode_buffer, s->decode_buffer_size, 1)) < 0)
472 /* render the final PAL8 frame */
473 if (s->vector_height == 4)
477 for (y = 0; y < s->height; y += s->vector_height) {
478 for (x = 0; x < s->width; x += 4, lobytes++, hibytes++) {
479 pixel_ptr = y * s->frame.linesize[0] + x;
481 /* get the vector index, the method for which varies according to
482 * VQA file version */
483 switch (s->vqa_version) {
486 lobyte = s->decode_buffer[lobytes * 2];
487 hibyte = s->decode_buffer[(lobytes * 2) + 1];
488 vector_index = ((hibyte << 8) | lobyte) >> 3;
489 vector_index <<= index_shift;
490 lines = s->vector_height;
491 /* uniform color fill - a quick hack */
492 if (hibyte == 0xFF) {
494 s->frame.data[0][pixel_ptr + 0] = 255 - lobyte;
495 s->frame.data[0][pixel_ptr + 1] = 255 - lobyte;
496 s->frame.data[0][pixel_ptr + 2] = 255 - lobyte;
497 s->frame.data[0][pixel_ptr + 3] = 255 - lobyte;
498 pixel_ptr += s->frame.linesize[0];
505 lobyte = s->decode_buffer[lobytes];
506 hibyte = s->decode_buffer[hibytes];
507 vector_index = (hibyte << 8) | lobyte;
508 vector_index <<= index_shift;
509 lines = s->vector_height;
513 /* not implemented yet */
519 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
520 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
521 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
522 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
523 pixel_ptr += s->frame.linesize[0];
528 /* handle partial codebook */
529 if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
530 /* a chunk should not have both chunk types */
531 av_log(s->avctx, AV_LOG_ERROR, "problem: found both CBP0 and CBPZ chunks\n");
532 return AVERROR_INVALIDDATA;
535 if (cbp0_chunk != -1) {
537 bytestream2_seek(&s->gb, cbp0_chunk, SEEK_SET);
538 chunk_size = bytestream2_get_be32(&s->gb);
540 if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {
541 av_log(s->avctx, AV_LOG_ERROR, "cbp0 chunk too large (0x%X bytes)\n", chunk_size);
542 return AVERROR_INVALIDDATA;
545 /* accumulate partial codebook */
546 bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
548 s->next_codebook_buffer_index += chunk_size;
550 s->partial_countdown--;
551 if (s->partial_countdown <= 0) {
553 /* time to replace codebook */
554 memcpy(s->codebook, s->next_codebook_buffer,
555 s->next_codebook_buffer_index);
557 /* reset accounting */
558 s->next_codebook_buffer_index = 0;
559 s->partial_countdown = s->partial_count;
563 if (cbpz_chunk != -1) {
565 bytestream2_seek(&s->gb, cbpz_chunk, SEEK_SET);
566 chunk_size = bytestream2_get_be32(&s->gb);
568 if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {
569 av_log(s->avctx, AV_LOG_ERROR, "cbpz chunk too large (0x%X bytes)\n", chunk_size);
570 return AVERROR_INVALIDDATA;
573 /* accumulate partial codebook */
574 bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
576 s->next_codebook_buffer_index += chunk_size;
578 s->partial_countdown--;
579 if (s->partial_countdown <= 0) {
580 bytestream2_init(&s->gb, s->next_codebook_buffer, s->next_codebook_buffer_index);
581 /* decompress codebook */
582 if ((res = decode_format80(s, s->next_codebook_buffer_index,
583 s->codebook, s->codebook_size, 0)) < 0)
586 /* reset accounting */
587 s->next_codebook_buffer_index = 0;
588 s->partial_countdown = s->partial_count;
595 static int vqa_decode_frame(AVCodecContext *avctx,
596 void *data, int *got_frame,
599 VqaContext *s = avctx->priv_data;
602 if (s->frame.data[0])
603 avctx->release_buffer(avctx, &s->frame);
605 if ((res = ff_get_buffer(avctx, &s->frame)) < 0) {
606 av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
610 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
611 if ((res = vqa_decode_chunk(s)) < 0)
614 /* make the palette available on the way out */
615 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
616 s->frame.palette_has_changed = 1;
619 *(AVFrame*)data = s->frame;
621 /* report that the buffer was completely consumed */
625 static av_cold int vqa_decode_end(AVCodecContext *avctx)
627 VqaContext *s = avctx->priv_data;
629 av_freep(&s->codebook);
630 av_freep(&s->next_codebook_buffer);
631 av_freep(&s->decode_buffer);
633 if (s->frame.data[0])
634 avctx->release_buffer(avctx, &s->frame);
639 AVCodec ff_vqa_decoder = {
641 .type = AVMEDIA_TYPE_VIDEO,
642 .id = AV_CODEC_ID_WS_VQA,
643 .priv_data_size = sizeof(VqaContext),
644 .init = vqa_decode_init,
645 .close = vqa_decode_end,
646 .decode = vqa_decode_frame,
647 .capabilities = CODEC_CAP_DR1,
648 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios VQA (Vector Quantized Animation) video"),