2 * Interplay C93 video decoder
3 * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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
23 #include "bytestream.h"
32 C93_8X8_FROM_PREV = 0x02,
33 C93_4X4_FROM_PREV = 0x06,
34 C93_4X4_FROM_CURR = 0x07,
35 C93_8X8_2COLOR = 0x08,
36 C93_4X4_2COLOR = 0x0A,
37 C93_4X4_4COLOR_GRP = 0x0B,
38 C93_4X4_4COLOR = 0x0D,
46 #define C93_HAS_PALETTE 0x01
47 #define C93_FIRST_FRAME 0x02
49 static av_cold int decode_init(AVCodecContext *avctx)
51 C93DecoderContext *s = avctx->priv_data;
52 avctx->pix_fmt = AV_PIX_FMT_PAL8;
53 avcodec_get_frame_defaults(&s->pictures[0]);
54 avcodec_get_frame_defaults(&s->pictures[1]);
58 static av_cold int decode_end(AVCodecContext *avctx)
60 C93DecoderContext * const c93 = avctx->priv_data;
62 av_frame_unref(&c93->pictures[0]);
63 av_frame_unref(&c93->pictures[1]);
68 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
69 uint8_t *from, int offset, int height, int stride)
73 int from_x = offset % WIDTH;
74 int from_y = offset / WIDTH;
75 int overflow = from_x + width - WIDTH;
78 /* silently ignoring predictive blocks in first frame */
82 if (from_y + height > HEIGHT) {
83 av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
85 return AVERROR_INVALIDDATA;
90 for (i = 0; i < height; i++) {
91 memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
95 for (i = 0; i < height; i++) {
96 memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
102 static inline void draw_n_color(uint8_t *out, int stride, int width,
103 int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
106 for (y = 0; y < height; y++) {
108 cols[0] = grps[3 * (y >> 1)];
109 for (x = 0; x < width; x++) {
111 cols[1]= grps[(x >> 1) + 1];
112 out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
118 static int decode_frame(AVCodecContext *avctx, void *data,
119 int *got_frame, AVPacket *avpkt)
121 const uint8_t *buf = avpkt->data;
122 int buf_size = avpkt->size;
123 C93DecoderContext * const c93 = avctx->priv_data;
124 AVFrame * const newpic = &c93->pictures[c93->currentpic];
125 AVFrame * const oldpic = &c93->pictures[c93->currentpic^1];
128 int stride, ret, i, x, y, b, bt = 0;
130 c93->currentpic ^= 1;
132 if ((ret = ff_reget_buffer(avctx, newpic)) < 0)
135 stride = newpic->linesize[0];
137 bytestream2_init(&gb, buf, buf_size);
138 b = bytestream2_get_byte(&gb);
139 if (b & C93_FIRST_FRAME) {
140 newpic->pict_type = AV_PICTURE_TYPE_I;
141 newpic->key_frame = 1;
143 newpic->pict_type = AV_PICTURE_TYPE_P;
144 newpic->key_frame = 0;
147 for (y = 0; y < HEIGHT; y += 8) {
148 out = newpic->data[0] + y * stride;
149 for (x = 0; x < WIDTH; x += 8) {
150 uint8_t *copy_from = oldpic->data[0];
151 unsigned int offset, j;
152 uint8_t cols[4], grps[4];
153 C93BlockType block_type;
156 bt = bytestream2_get_byte(&gb);
158 block_type= bt & 0x0F;
159 switch (block_type) {
160 case C93_8X8_FROM_PREV:
161 offset = bytestream2_get_le16(&gb);
162 if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
166 case C93_4X4_FROM_CURR:
167 copy_from = newpic->data[0];
168 case C93_4X4_FROM_PREV:
169 for (j = 0; j < 8; j += 4) {
170 for (i = 0; i < 8; i += 4) {
171 int offset = bytestream2_get_le16(&gb);
172 int from_x = offset % WIDTH;
173 int from_y = offset / WIDTH;
174 if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
175 (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
176 avpriv_request_sample(avctx, "block overlap %d %d %d %d\n", from_x, x+i, from_y, y+j);
177 return AVERROR_INVALIDDATA;
179 if ((ret = copy_block(avctx, &out[j*stride+i],
180 copy_from, offset, 4, stride)) < 0)
187 bytestream2_get_buffer(&gb, cols, 2);
188 for (i = 0; i < 8; i++) {
189 draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
190 NULL, bytestream2_get_byte(&gb));
197 case C93_4X4_4COLOR_GRP:
198 for (j = 0; j < 8; j += 4) {
199 for (i = 0; i < 8; i += 4) {
200 if (block_type == C93_4X4_2COLOR) {
201 bytestream2_get_buffer(&gb, cols, 2);
202 draw_n_color(out + i + j*stride, stride, 4, 4,
203 1, cols, NULL, bytestream2_get_le16(&gb));
204 } else if (block_type == C93_4X4_4COLOR) {
205 bytestream2_get_buffer(&gb, cols, 4);
206 draw_n_color(out + i + j*stride, stride, 4, 4,
207 2, cols, NULL, bytestream2_get_le32(&gb));
209 bytestream2_get_buffer(&gb, grps, 4);
210 draw_n_color(out + i + j*stride, stride, 4, 4,
211 1, cols, grps, bytestream2_get_le16(&gb));
221 for (j = 0; j < 8; j++)
222 bytestream2_get_buffer(&gb, out + j*stride, 8);
226 av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
228 return AVERROR_INVALIDDATA;
235 if (b & C93_HAS_PALETTE) {
236 uint32_t *palette = (uint32_t *) newpic->data[1];
237 for (i = 0; i < 256; i++) {
238 palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
240 newpic->palette_has_changed = 1;
243 memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
246 if ((ret = av_frame_ref(data, newpic)) < 0)
253 AVCodec ff_c93_decoder = {
255 .type = AVMEDIA_TYPE_VIDEO,
256 .id = AV_CODEC_ID_C93,
257 .priv_data_size = sizeof(C93DecoderContext),
260 .decode = decode_frame,
261 .capabilities = CODEC_CAP_DR1,
262 .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),