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')
96 #define vqa_debug printf
98 static inline void vqa_debug(const char *format, ...) { }
101 typedef struct VqaContext {
103 AVCodecContext *avctx;
106 const unsigned char *buf;
109 uint32_t palette[PALETTE_COUNT];
111 int width; /* width of a frame */
112 int height; /* height of a frame */
113 int vector_width; /* width of individual vector */
114 int vector_height; /* height of individual vector */
115 int vqa_version; /* this should be either 1, 2 or 3 */
117 unsigned char *codebook; /* the current codebook */
119 unsigned char *next_codebook_buffer; /* accumulator for next codebook */
120 int next_codebook_buffer_index;
122 unsigned char *decode_buffer;
123 int decode_buffer_size;
125 /* number of frames to go before replacing codebook */
126 int partial_countdown;
131 static av_cold int vqa_decode_init(AVCodecContext *avctx)
133 VqaContext *s = avctx->priv_data;
134 unsigned char *vqa_header;
135 int i, j, codebook_index;
138 avctx->pix_fmt = PIX_FMT_PAL8;
140 /* make sure the extradata made it */
141 if (s->avctx->extradata_size != VQA_HEADER_SIZE) {
142 av_log(s->avctx, AV_LOG_ERROR, " VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);
146 /* load up the VQA parameters from the header */
147 vqa_header = (unsigned char *)s->avctx->extradata;
148 s->vqa_version = vqa_header[0];
149 s->width = AV_RL16(&vqa_header[6]);
150 s->height = AV_RL16(&vqa_header[8]);
151 if(av_image_check_size(s->width, s->height, 0, avctx)){
152 s->width= s->height= 0;
155 s->vector_width = vqa_header[10];
156 s->vector_height = vqa_header[11];
157 s->partial_count = s->partial_countdown = vqa_header[13];
159 /* the vector dimensions have to meet very stringent requirements */
160 if ((s->vector_width != 4) ||
161 ((s->vector_height != 2) && (s->vector_height != 4))) {
162 /* return without further initialization */
166 /* allocate codebooks */
167 s->codebook_size = MAX_CODEBOOK_SIZE;
168 s->codebook = av_malloc(s->codebook_size);
169 s->next_codebook_buffer = av_malloc(s->codebook_size);
171 /* initialize the solid-color vectors */
172 if (s->vector_height == 4) {
173 codebook_index = 0xFF00 * 16;
174 for (i = 0; i < 256; i++)
175 for (j = 0; j < 16; j++)
176 s->codebook[codebook_index++] = i;
178 codebook_index = 0xF00 * 8;
179 for (i = 0; i < 256; i++)
180 for (j = 0; j < 8; j++)
181 s->codebook[codebook_index++] = i;
183 s->next_codebook_buffer_index = 0;
185 /* allocate decode buffer */
186 s->decode_buffer_size = (s->width / s->vector_width) *
187 (s->height / s->vector_height) * 2;
188 s->decode_buffer = av_malloc(s->decode_buffer_size);
190 avcodec_get_frame_defaults(&s->frame);
191 s->frame.data[0] = NULL;
196 #define CHECK_COUNT() \
197 if (dest_index + count > dest_size) { \
198 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
199 av_log(NULL, AV_LOG_ERROR, " VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \
200 dest_index, count, dest_size); \
204 static void decode_format80(const unsigned char *src, int src_size,
205 unsigned char *dest, int dest_size, int check_size) {
214 while (src_index < src_size) {
216 vqa_debug(" opcode %02X: ", src[src_index]);
218 /* 0x80 means that frame is finished */
219 if (src[src_index] == 0x80)
222 if (dest_index >= dest_size) {
223 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",
224 dest_index, dest_size);
228 if (src[src_index] == 0xFF) {
231 count = AV_RL16(&src[src_index]);
233 src_pos = AV_RL16(&src[src_index]);
235 vqa_debug("(1) copy %X bytes from absolute pos %X\n", count, src_pos);
237 for (i = 0; i < count; i++)
238 dest[dest_index + i] = dest[src_pos + i];
241 } else if (src[src_index] == 0xFE) {
244 count = AV_RL16(&src[src_index]);
246 color = src[src_index++];
247 vqa_debug("(2) set %X bytes to %02X\n", count, color);
249 memset(&dest[dest_index], color, count);
252 } else if ((src[src_index] & 0xC0) == 0xC0) {
254 count = (src[src_index++] & 0x3F) + 3;
255 src_pos = AV_RL16(&src[src_index]);
257 vqa_debug("(3) copy %X bytes from absolute pos %X\n", count, src_pos);
259 for (i = 0; i < count; i++)
260 dest[dest_index + i] = dest[src_pos + i];
263 } else if (src[src_index] > 0x80) {
265 count = src[src_index++] & 0x3F;
266 vqa_debug("(4) copy %X bytes from source to dest\n", count);
268 memcpy(&dest[dest_index], &src[src_index], count);
274 count = ((src[src_index] & 0x70) >> 4) + 3;
275 src_pos = AV_RB16(&src[src_index]) & 0x0FFF;
277 vqa_debug("(5) copy %X bytes from relpos %X\n", count, src_pos);
279 for (i = 0; i < count; i++)
280 dest[dest_index + i] = dest[dest_index - src_pos + i];
285 /* validate that the entire destination buffer was filled; this is
286 * important for decoding frame maps since each vector needs to have a
287 * codebook entry; it is not important for compressed codebooks because
288 * not every entry needs to be filled */
290 if (dest_index < dest_size)
291 av_log(NULL, AV_LOG_ERROR, " VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",
292 dest_index, dest_size);
295 static void vqa_decode_chunk(VqaContext *s)
297 unsigned int chunk_type;
298 unsigned int chunk_size;
300 unsigned int index = 0;
302 unsigned char r, g, b;
316 int vector_index = 0;
320 int hibytes = s->decode_buffer_size / 2;
322 /* first, traverse through the frame and find the subchunks */
323 while (index < s->size) {
325 chunk_type = AV_RB32(&s->buf[index]);
326 chunk_size = AV_RB32(&s->buf[index + 4]);
328 switch (chunk_type) {
359 av_log(s->avctx, AV_LOG_ERROR, " VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",
360 (chunk_type >> 24) & 0xFF,
361 (chunk_type >> 16) & 0xFF,
362 (chunk_type >> 8) & 0xFF,
363 (chunk_type >> 0) & 0xFF,
368 byte_skip = chunk_size & 0x01;
369 index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
372 /* next, deal with the palette */
373 if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
375 /* a chunk should not have both chunk types */
376 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CPL0 and CPLZ chunks\n");
380 /* decompress the palette chunk */
381 if (cplz_chunk != -1) {
383 /* yet to be handled */
387 /* convert the RGB palette into the machine's endian format */
388 if (cpl0_chunk != -1) {
390 chunk_size = AV_RB32(&s->buf[cpl0_chunk + 4]);
391 /* sanity check the palette size */
392 if (chunk_size / 3 > 256) {
393 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found a palette chunk with %d colors\n",
397 cpl0_chunk += CHUNK_PREAMBLE_SIZE;
398 for (i = 0; i < chunk_size / 3; i++) {
399 /* scale by 4 to transform 6-bit palette -> 8-bit */
400 r = s->buf[cpl0_chunk++] * 4;
401 g = s->buf[cpl0_chunk++] * 4;
402 b = s->buf[cpl0_chunk++] * 4;
403 s->palette[i] = (r << 16) | (g << 8) | (b);
407 /* next, look for a full codebook */
408 if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
410 /* a chunk should not have both chunk types */
411 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: found both CBF0 and CBFZ chunks\n");
415 /* decompress the full codebook chunk */
416 if (cbfz_chunk != -1) {
418 chunk_size = AV_RB32(&s->buf[cbfz_chunk + 4]);
419 cbfz_chunk += CHUNK_PREAMBLE_SIZE;
420 decode_format80(&s->buf[cbfz_chunk], chunk_size,
421 s->codebook, s->codebook_size, 0);
424 /* copy a full codebook */
425 if (cbf0_chunk != -1) {
427 chunk_size = AV_RB32(&s->buf[cbf0_chunk + 4]);
428 /* sanity check the full codebook size */
429 if (chunk_size > MAX_CODEBOOK_SIZE) {
430 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",
434 cbf0_chunk += CHUNK_PREAMBLE_SIZE;
436 memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
439 /* decode the frame */
440 if (vptz_chunk == -1) {
442 /* something is wrong if there is no VPTZ chunk */
443 av_log(s->avctx, AV_LOG_ERROR, " VQA video: problem: no VPTZ chunk found\n");
447 chunk_size = AV_RB32(&s->buf[vptz_chunk + 4]);
448 vptz_chunk += CHUNK_PREAMBLE_SIZE;
449 decode_format80(&s->buf[vptz_chunk], chunk_size,
450 s->decode_buffer, s->decode_buffer_size, 1);
452 /* render the final PAL8 frame */
453 if (s->vector_height == 4)
457 for (y = 0; y < s->frame.linesize[0] * s->height;
458 y += s->frame.linesize[0] * s->vector_height) {
460 for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
463 /* get the vector index, the method for which varies according to
464 * VQA file version */
465 switch (s->vqa_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,
569 const uint8_t *buf = avpkt->data;
570 int buf_size = avpkt->size;
571 VqaContext *s = avctx->priv_data;
576 if (s->frame.data[0])
577 avctx->release_buffer(avctx, &s->frame);
579 if (avctx->get_buffer(avctx, &s->frame)) {
580 av_log(s->avctx, AV_LOG_ERROR, " VQA Video: get_buffer() failed\n");
586 /* make the palette available on the way out */
587 memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
588 s->frame.palette_has_changed = 1;
590 *data_size = sizeof(AVFrame);
591 *(AVFrame*)data = s->frame;
593 /* report that the buffer was completely consumed */
597 static av_cold int vqa_decode_end(AVCodecContext *avctx)
599 VqaContext *s = avctx->priv_data;
601 av_free(s->codebook);
602 av_free(s->next_codebook_buffer);
603 av_free(s->decode_buffer);
605 if (s->frame.data[0])
606 avctx->release_buffer(avctx, &s->frame);
611 AVCodec ff_vqa_decoder = {
621 .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios VQA (Vector Quantized Animation) video"),