3 * Copyright (c) 2006 Konstantin Shishkov
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 * Karl Morton's Video Codec decoder
31 #include "bytestream.h"
33 #define KMVC_KEYFRAME 0x80
34 #define KMVC_PALETTE 0x40
35 #define KMVC_METHOD 0x0F
40 typedef struct KmvcContext {
41 AVCodecContext *avctx;
52 typedef struct BitBuf {
57 #define BLK(data, x, y) data[(x) + (y) * 320]
59 #define kmvc_init_getbits(bb, g) bb.bits = 7; bb.bitbuf = bytestream2_get_byte(g);
61 #define kmvc_getbit(bb, g, res) {\
63 if (bb.bitbuf & (1 << bb.bits)) res = 1; \
66 bb.bitbuf = bytestream2_get_byte(g); \
71 static int kmvc_decode_intra_8x8(KmvcContext * ctx, int w, int h)
77 int l0x, l1x, l0y, l1y;
80 kmvc_init_getbits(bb, &ctx->g);
82 for (by = 0; by < h; by += 8)
83 for (bx = 0; bx < w; bx += 8) {
84 if (!bytestream2_get_bytes_left(&ctx->g)) {
85 av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
86 return AVERROR_INVALIDDATA;
88 kmvc_getbit(bb, &ctx->g, res);
89 if (!res) { // fill whole 8x8 block
90 val = bytestream2_get_byte(&ctx->g);
91 for (i = 0; i < 64; i++)
92 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
93 } else { // handle four 4x4 subblocks
94 for (i = 0; i < 4; i++) {
95 l0x = bx + (i & 1) * 4;
96 l0y = by + (i & 2) * 2;
97 kmvc_getbit(bb, &ctx->g, res);
99 kmvc_getbit(bb, &ctx->g, res);
100 if (!res) { // fill whole 4x4 block
101 val = bytestream2_get_byte(&ctx->g);
102 for (j = 0; j < 16; j++)
103 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
104 } else { // copy block from already decoded place
105 val = bytestream2_get_byte(&ctx->g);
108 for (j = 0; j < 16; j++)
109 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
110 BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
112 } else { // descend to 2x2 sub-sub-blocks
113 for (j = 0; j < 4; j++) {
114 l1x = l0x + (j & 1) * 2;
116 kmvc_getbit(bb, &ctx->g, res);
118 kmvc_getbit(bb, &ctx->g, res);
119 if (!res) { // fill whole 2x2 block
120 val = bytestream2_get_byte(&ctx->g);
121 BLK(ctx->cur, l1x, l1y) = val;
122 BLK(ctx->cur, l1x + 1, l1y) = val;
123 BLK(ctx->cur, l1x, l1y + 1) = val;
124 BLK(ctx->cur, l1x + 1, l1y + 1) = val;
125 } else { // copy block from already decoded place
126 val = bytestream2_get_byte(&ctx->g);
129 BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
130 BLK(ctx->cur, l1x + 1, l1y) =
131 BLK(ctx->cur, l1x + 1 - mx, l1y - my);
132 BLK(ctx->cur, l1x, l1y + 1) =
133 BLK(ctx->cur, l1x - mx, l1y + 1 - my);
134 BLK(ctx->cur, l1x + 1, l1y + 1) =
135 BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
137 } else { // read values for block
138 BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
139 BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
140 BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
141 BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
152 static int kmvc_decode_inter_8x8(KmvcContext * ctx, int w, int h)
158 int l0x, l1x, l0y, l1y;
161 kmvc_init_getbits(bb, &ctx->g);
163 for (by = 0; by < h; by += 8)
164 for (bx = 0; bx < w; bx += 8) {
165 kmvc_getbit(bb, &ctx->g, res);
167 kmvc_getbit(bb, &ctx->g, res);
168 if (!res) { // fill whole 8x8 block
169 if (!bytestream2_get_bytes_left(&ctx->g)) {
170 av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
171 return AVERROR_INVALIDDATA;
173 val = bytestream2_get_byte(&ctx->g);
174 for (i = 0; i < 64; i++)
175 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
176 } else { // copy block from previous frame
177 for (i = 0; i < 64; i++)
178 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
179 BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
181 } else { // handle four 4x4 subblocks
182 if (!bytestream2_get_bytes_left(&ctx->g)) {
183 av_log(ctx->avctx, AV_LOG_ERROR, "Data overrun\n");
184 return AVERROR_INVALIDDATA;
186 for (i = 0; i < 4; i++) {
187 l0x = bx + (i & 1) * 4;
188 l0y = by + (i & 2) * 2;
189 kmvc_getbit(bb, &ctx->g, res);
191 kmvc_getbit(bb, &ctx->g, res);
192 if (!res) { // fill whole 4x4 block
193 val = bytestream2_get_byte(&ctx->g);
194 for (j = 0; j < 16; j++)
195 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
196 } else { // copy block
197 val = bytestream2_get_byte(&ctx->g);
198 mx = (val & 0xF) - 8;
200 for (j = 0; j < 16; j++)
201 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
202 BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
204 } else { // descend to 2x2 sub-sub-blocks
205 for (j = 0; j < 4; j++) {
206 l1x = l0x + (j & 1) * 2;
208 kmvc_getbit(bb, &ctx->g, res);
210 kmvc_getbit(bb, &ctx->g, res);
211 if (!res) { // fill whole 2x2 block
212 val = bytestream2_get_byte(&ctx->g);
213 BLK(ctx->cur, l1x, l1y) = val;
214 BLK(ctx->cur, l1x + 1, l1y) = val;
215 BLK(ctx->cur, l1x, l1y + 1) = val;
216 BLK(ctx->cur, l1x + 1, l1y + 1) = val;
217 } else { // copy block
218 val = bytestream2_get_byte(&ctx->g);
219 mx = (val & 0xF) - 8;
221 BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
222 BLK(ctx->cur, l1x + 1, l1y) =
223 BLK(ctx->prev, l1x + 1 + mx, l1y + my);
224 BLK(ctx->cur, l1x, l1y + 1) =
225 BLK(ctx->prev, l1x + mx, l1y + 1 + my);
226 BLK(ctx->cur, l1x + 1, l1y + 1) =
227 BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
229 } else { // read values for block
230 BLK(ctx->cur, l1x, l1y) = bytestream2_get_byte(&ctx->g);
231 BLK(ctx->cur, l1x + 1, l1y) = bytestream2_get_byte(&ctx->g);
232 BLK(ctx->cur, l1x, l1y + 1) = bytestream2_get_byte(&ctx->g);
233 BLK(ctx->cur, l1x + 1, l1y + 1) = bytestream2_get_byte(&ctx->g);
244 static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt)
246 KmvcContext *const ctx = avctx->priv_data;
251 const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
253 bytestream2_init(&ctx->g, avpkt->data, avpkt->size);
254 if (ctx->pic.data[0])
255 avctx->release_buffer(avctx, &ctx->pic);
257 ctx->pic.reference = 3;
258 ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
259 if (avctx->get_buffer(avctx, &ctx->pic) < 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)] = 0xFFU << 24 | 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 ctx->pic.key_frame = 1;
278 ctx->pic.pict_type = AV_PICTURE_TYPE_I;
280 ctx->pic.key_frame = 0;
281 ctx->pic.pict_type = AV_PICTURE_TYPE_P;
284 if (header & KMVC_PALETTE) {
285 ctx->pic.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] = 0xFFU << 24 | bytestream2_get_be24(&ctx->g);
293 ctx->pic.palette_has_changed = 1;
294 memcpy(ctx->pal, pal, AVPALETTE_SIZE);
299 ctx->pic.palette_has_changed = 1;
302 /* make the palette available on the way out */
303 memcpy(ctx->pic.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);
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);
328 out = ctx->pic.data[0];
330 for (i = 0; i < avctx->height; i++) {
331 memcpy(out, src, avctx->width);
333 out += ctx->pic.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;
345 *data_size = sizeof(AVFrame);
346 *(AVFrame *) data = ctx->pic;
348 /* always report that the buffer was completely consumed */
357 static av_cold int decode_init(AVCodecContext * avctx)
359 KmvcContext *const c = avctx->priv_data;
364 if (avctx->width > 320 || avctx->height > 200) {
365 av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
369 c->frm0 = av_mallocz(320 * 200);
370 c->frm1 = av_mallocz(320 * 200);
374 for (i = 0; i < 256; i++) {
375 c->pal[i] = 0xFF << 24 | i * 0x10101;
378 if (avctx->extradata_size < 12) {
379 av_log(NULL, 0, "Extradata missing, decoding may not work properly...\n");
382 c->palsize = AV_RL16(avctx->extradata + 10);
385 if (avctx->extradata_size == 1036) { // palette in extradata
386 uint8_t *src = avctx->extradata + 12;
387 for (i = 0; i < 256; i++) {
388 c->pal[i] = AV_RL32(src);
394 avcodec_get_frame_defaults(&c->pic);
395 avctx->pix_fmt = PIX_FMT_PAL8;
403 * Uninit kmvc decoder
405 static av_cold int decode_end(AVCodecContext * avctx)
407 KmvcContext *const c = avctx->priv_data;
412 avctx->release_buffer(avctx, &c->pic);
417 AVCodec ff_kmvc_decoder = {
419 .type = AVMEDIA_TYPE_VIDEO,
421 .priv_data_size = sizeof(KmvcContext),
424 .decode = decode_frame,
425 .capabilities = CODEC_CAP_DR1,
426 .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),