3 * Copyright (c) 2006 Konstantin Shishkov
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
24 * Karl Morton's Video Codec decoder
31 #include "bytestream.h"
33 #include "libavutil/common.h"
35 #define KMVC_KEYFRAME 0x80
36 #define KMVC_PALETTE 0x40
37 #define KMVC_METHOD 0x0F
38 #define MAX_PALSIZE 256
43 typedef struct KmvcContext {
44 AVCodecContext *avctx;
48 uint32_t pal[MAX_PALSIZE];
50 uint8_t frm0[320 * 200], frm1[320 * 200];
54 typedef struct BitBuf {
59 #define BLK(data, x, y) data[av_clip((x) + (y) * 320, 0, 320 * 200 -1)]
61 #define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
63 #define kmvc_getbit(bb, g, res) {\
65 if (bb.bitbuf & (1 << bb.bits)) res = 1; \
68 bb.bitbuf = bytestream2_get_byte(g); \
73 static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
79 int l0x, l1x, l0y, l1y;
82 kmvc_init_getbits(bb, &ctx->g);
84 for (by = 0; by < h; by += 8)
85 for (bx = 0; bx < w; bx += 8) {
86 if (!bytestream2_get_bytes_left(&ctx->g)) {
87 av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
88 return AVERROR_INVALIDDATA;
90 kmvc_getbit(bb, &ctx->g, res);
91 if (!res) { // fill whole 8x8 block
92 val = bytestream2_get_byte(&ctx->g);
93 for (i = 0; i < 64; i++)
94 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
95 } else { // handle four 4x4 subblocks
96 for (i = 0; i < 4; i++) {
97 l0x = bx + (i & 1) * 4;
98 l0y = by + (i & 2) * 2;
99 kmvc_getbit(bb, &ctx->g, res);
101 kmvc_getbit(bb, &ctx->g, res);
102 if (!res) { // fill whole 4x4 block
103 val = bytestream2_get_byte(&ctx->g);
104 for (j = 0; j < 16; j++)
105 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
106 } else { // copy block from already decoded place
107 val = bytestream2_get_byte(&ctx->g);
110 for (j = 0; j < 16; j++)
111 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
112 BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
114 } else { // descend to 2x2 sub-sub-blocks
115 for (j = 0; j < 4; j++) {
116 l1x = l0x + (j & 1) * 2;
118 kmvc_getbit(bb, &ctx->g, res);
120 kmvc_getbit(bb, &ctx->g, res);
121 if (!res) { // fill whole 2x2 block
122 val = bytestream2_get_byte(&ctx->g);
123 BLK(ctx->cur, l1x, l1y) = val;
124 BLK(ctx->cur, l1x + 1, l1y) = val;
125 BLK(ctx->cur, l1x, l1y + 1) = val;
126 BLK(ctx->cur, l1x + 1, l1y + 1) = val;
127 } else { // copy block from already decoded place
128 val = bytestream2_get_byte(&ctx->g);
131 BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
132 BLK(ctx->cur, l1x + 1, l1y) =
133 BLK(ctx->cur, l1x + 1 - mx, l1y - my);
134 BLK(ctx->cur, l1x, l1y + 1) =
135 BLK(ctx->cur, l1x - mx, l1y + 1 - my);
136 BLK(ctx->cur, l1x + 1, l1y + 1) =
137 BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
139 } else { // read values for block
140 BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
141 BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
142 BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
143 BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
154 static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
160 int l0x, l1x, l0y, l1y;
163 kmvc_init_getbits(bb, &ctx->g);
165 for (by = 0; by < h; by += 8)
166 for (bx = 0; bx < w; bx += 8) {
167 kmvc_getbit(bb, &ctx->g, res);
169 kmvc_getbit(bb, &ctx->g, res);
170 if (!res) { // fill whole 8x8 block
171 if (!bytestream2_get_bytes_left(&ctx->g)) {
172 av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
173 return AVERROR_INVALIDDATA;
175 val = bytestream2_get_byte(&ctx->g);
176 for (i = 0; i < 64; i++)
177 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
178 } else { // copy block from previous frame
179 for (i = 0; i < 64; i++)
180 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
181 BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
183 } else { // handle four 4x4 subblocks
184 if (!bytestream2_get_bytes_left(&ctx->g)) {
185 av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
186 return AVERROR_INVALIDDATA;
188 for (i = 0; i < 4; i++) {
189 l0x = bx + (i & 1) * 4;
190 l0y = by + (i & 2) * 2;
191 kmvc_getbit(bb, &ctx->g, res);
193 kmvc_getbit(bb, &ctx->g, res);
194 if (!res) { // fill whole 4x4 block
195 val = bytestream2_get_byte(&ctx->g);
196 for (j = 0; j < 16; j++)
197 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
198 } else { // copy block
199 val = bytestream2_get_byte(&ctx->g);
200 mx = (val & 0xF) - 8;
202 for (j = 0; j < 16; j++)
203 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
204 BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
206 } else { // descend to 2x2 sub-sub-blocks
207 for (j = 0; j < 4; j++) {
208 l1x = l0x + (j & 1) * 2;
210 kmvc_getbit(bb, &ctx->g, res);
212 kmvc_getbit(bb, &ctx->g, res);
213 if (!res) { // fill whole 2x2 block
214 val = bytestream2_get_byte(&ctx->g);
215 BLK(ctx->cur, l1x, l1y) = val;
216 BLK(ctx->cur, l1x + 1, l1y) = val;
217 BLK(ctx->cur, l1x, l1y + 1) = val;
218 BLK(ctx->cur, l1x + 1, l1y + 1) = val;
219 } else { // copy block
220 val = bytestream2_get_byte(&ctx->g);
221 mx = (val & 0xF) - 8;
223 BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
224 BLK(ctx->cur, l1x + 1, l1y) =
225 BLK(ctx->prev, l1x + 1 + mx, l1y + my);
226 BLK(ctx->cur, l1x, l1y + 1) =
227 BLK(ctx->prev, l1x + mx, l1y + 1 + my);
228 BLK(ctx->cur, l1x + 1, l1y + 1) =
229 BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
231 } else { // read values for block
232 BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
233 BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
234 BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
235 BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
246 static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame,
249 KmvcContext *const ctx = avctx->priv_data;
250 AVFrame *frame = data;
255 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
257 bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
259 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
260 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
264 header = bytestream2_get_byte(&ctx->g);
266 /* blocksize 127 is really palette change event */
267 if (bytestream2_peek_byte(&ctx->g) == 127) {
268 bytestream2_skip(&ctx->g, 3);
269 for (i = 0; i < 127; i++) {
270 ctx->pal[i + (header & 0x81)] = bytestream2_get_be24(&ctx->g);
271 bytestream2_skip(&ctx->g, 1);
273 bytestream2_seek(&ctx->g, -127 * 4 - 3, SEEK_CUR);
276 if (header & KMVC_KEYFRAME) {
277 frame->key_frame = 1;
278 frame->pict_type = AV_PICTURE_TYPE_I;
280 frame->key_frame = 0;
281 frame->pict_type = AV_PICTURE_TYPE_P;
284 if (header & KMVC_PALETTE) {
285 frame->palette_has_changed = 1;
286 // palette starts from index 1 and has 127 entries
287 for (i = 1; i <= ctx->palsize; i++) {
288 ctx->pal[i] = bytestream2_get_be24(&ctx->g);
293 frame->palette_has_changed = 1;
294 memcpy(ctx->pal, pal, AVPALETTE_SIZE);
299 frame->palette_has_changed = 1;
302 /* make the palette available on the way out */
303 memcpy(frame->data[1], ctx->pal, 1024);
305 blocksize = bytestream2_get_byte(&ctx->g);
307 if (blocksize != 8 && blocksize != 127) {
308 av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
309 return AVERROR_INVALIDDATA;
311 memset(ctx->cur, 0, 320 * 200);
312 switch (header & KMVC_METHOD) {
314 case 1: // used in palette changed event
315 memcpy(ctx->cur, ctx->prev, 320 * 200);
318 kmvc_decode_intra_8x8(ctx, avctx->width, avctx->height);
321 kmvc_decode_inter_8x8(ctx, avctx->width, avctx->height);
324 av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
325 return AVERROR_INVALIDDATA;
328 out = frame->data[0];
330 for (i = 0; i < avctx->height; i++) {
331 memcpy(out, src, avctx->width);
333 out += frame->linesize[0];
337 if (ctx->cur == ctx->frm0) {
338 ctx->cur = ctx->frm1;
339 ctx->prev = ctx->frm0;
341 ctx->cur = ctx->frm0;
342 ctx->prev = ctx->frm1;
347 /* always report that the buffer was completely consumed */
356 static av_cold int decode_init(AVCodecContext * avctx)
358 KmvcContext *const c = avctx->priv_data;
363 if (avctx->width > 320 || avctx->height > 200) {
364 av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
365 return AVERROR(EINVAL);
371 for (i = 0; i < 256; i++) {
372 c->pal[i] = i * 0x10101;
375 if (avctx->extradata_size < 12) {
376 av_log(avctx, AV_LOG_WARNING,
377 "Extradata missing, decoding may not work properly...\n");
380 c->palsize = AV_RL16(avctx->extradata + 10);
381 if (c->palsize >= MAX_PALSIZE) {
382 av_log(avctx, AV_LOG_ERROR, "KMVC palette too large\n");
383 return AVERROR_INVALIDDATA;
387 if (avctx->extradata_size == 1036) { // palette in extradata
388 uint8_t *src = avctx->extradata + 12;
389 for (i = 0; i < 256; i++) {
390 c->pal[i] = AV_RL32(src);
396 avctx->pix_fmt = AV_PIX_FMT_PAL8;
401 AVCodec ff_kmvc_decoder = {
403 .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
404 .type = AVMEDIA_TYPE_VIDEO,
405 .id = AV_CODEC_ID_KMVC,
406 .priv_data_size = sizeof(KmvcContext),
408 .decode = decode_frame,
409 .capabilities = AV_CODEC_CAP_DR1,