2 * Psygnosis YOP decoder
4 * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
5 * derived from the code by
6 * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
8 * This file is part of Libav.
10 * Libav is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * Libav is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with Libav; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/imgutils.h"
32 typedef struct YopDecContext {
33 AVCodecContext *avctx;
37 int frame_data_length;
46 // These tables are taken directly from:
47 // http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP
50 * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain
51 * the macroblock positions to be painted (taken as (0, B0, B1, B2)).
52 * Byte 3 contains the number of bytes consumed on the input,
53 * equal to max(bytes 0-2) + 1.
55 static const uint8_t paint_lut[15][4] =
56 {{1, 2, 3, 4}, {1, 2, 0, 3},
57 {1, 2, 1, 3}, {1, 2, 2, 3},
58 {1, 0, 2, 3}, {1, 0, 0, 2},
59 {1, 0, 1, 2}, {1, 1, 2, 3},
60 {0, 1, 2, 3}, {0, 1, 0, 2},
61 {1, 1, 0, 2}, {0, 1, 1, 2},
62 {0, 0, 1, 2}, {0, 0, 0, 1},
67 * Lookup table for copying macroblocks. Each entry contains the respective
68 * x and y pixel offset for the copy source.
70 static const int8_t motion_vector[16][2] =
81 static av_cold int yop_decode_init(AVCodecContext *avctx)
83 YopDecContext *s = avctx->priv_data;
86 if (avctx->width & 1 || avctx->height & 1 ||
87 av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
88 av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
89 return AVERROR_INVALIDDATA;
92 if (avctx->extradata_size < 3) {
93 av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata.\n");
94 return AVERROR_INVALIDDATA;
97 avctx->pix_fmt = AV_PIX_FMT_PAL8;
99 s->num_pal_colors = avctx->extradata[0];
100 s->first_color[0] = avctx->extradata[1];
101 s->first_color[1] = avctx->extradata[2];
103 if (s->num_pal_colors + s->first_color[0] > 256 ||
104 s->num_pal_colors + s->first_color[1] > 256) {
105 av_log(avctx, AV_LOG_ERROR,
106 "YOP: palette parameters invalid, header probably corrupt\n");
107 return AVERROR_INVALIDDATA;
114 * Paint a macroblock using the pattern in paint_lut.
115 * @param s codec context
116 * @param tag the tag that was in the nibble
118 static int yop_paint_block(YopDecContext *s, int linesize, int tag)
120 if (s->src_end - s->srcptr < paint_lut[tag][3]) {
121 av_log(s->avctx, AV_LOG_ERROR, "Packet too small.\n");
122 return AVERROR_INVALIDDATA;
125 s->dstptr[0] = s->srcptr[0];
126 s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
127 s->dstptr[linesize] = s->srcptr[paint_lut[tag][1]];
128 s->dstptr[linesize + 1] = s->srcptr[paint_lut[tag][2]];
130 // The number of src bytes consumed is in the last part of the lut entry.
131 s->srcptr += paint_lut[tag][3];
136 * Copy a previously painted macroblock to the current_block.
137 * @param copy_tag the tag that was in the nibble
139 static int yop_copy_previous_block(YopDecContext *s, int linesize, int copy_tag)
143 // Calculate position for the copy source
144 bufptr = s->dstptr + motion_vector[copy_tag][0] +
145 linesize * motion_vector[copy_tag][1];
146 if (bufptr < s->dstbuf) {
147 av_log(s->avctx, AV_LOG_ERROR,
148 "YOP: cannot decode, file probably corrupt\n");
149 return AVERROR_INVALIDDATA;
152 s->dstptr[0] = bufptr[0];
153 s->dstptr[1] = bufptr[1];
154 s->dstptr[linesize] = bufptr[linesize];
155 s->dstptr[linesize + 1] = bufptr[linesize + 1];
161 * Return the next nibble in sequence, consuming a new byte on the input
164 static uint8_t yop_get_next_nibble(YopDecContext *s)
169 ret = *s->low_nibble & 0xf;
170 s->low_nibble = NULL;
172 s->low_nibble = s->srcptr++;
173 ret = *s->low_nibble >> 4;
178 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
181 YopDecContext *s = avctx->priv_data;
182 AVFrame *frame = data;
183 int tag, firstcolor, is_odd_frame;
187 if (avpkt->size < 4 + 3 * s->num_pal_colors) {
188 av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
189 return AVERROR_INVALIDDATA;
192 ret = ff_get_buffer(avctx, frame, 0);
194 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
198 if (!avctx->frame_number)
199 memset(frame->data[1], 0, AVPALETTE_SIZE);
201 s->dstbuf = frame->data[0];
202 s->dstptr = frame->data[0];
203 s->srcptr = avpkt->data + 4;
204 s->src_end = avpkt->data + avpkt->size;
205 s->low_nibble = NULL;
207 is_odd_frame = avpkt->data[0];
208 firstcolor = s->first_color[is_odd_frame];
209 palette = (uint32_t *)frame->data[1];
211 for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3)
212 palette[i + firstcolor] = (s->srcptr[0] << 18) |
213 (s->srcptr[1] << 10) |
216 frame->palette_has_changed = 1;
218 for (y = 0; y < avctx->height; y += 2) {
219 for (x = 0; x < avctx->width; x += 2) {
220 if (s->srcptr - avpkt->data >= avpkt->size) {
221 av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
222 return AVERROR_INVALIDDATA;
225 tag = yop_get_next_nibble(s);
228 ret = yop_paint_block(s, frame->linesize[0], tag);
232 tag = yop_get_next_nibble(s);
233 ret = yop_copy_previous_block(s, frame->linesize[0], tag);
239 s->dstptr += 2*frame->linesize[0] - x;
246 AVCodec ff_yop_decoder = {
248 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
249 .type = AVMEDIA_TYPE_VIDEO,
250 .id = AV_CODEC_ID_YOP,
251 .priv_data_size = sizeof(YopDecContext),
252 .init = yop_decode_init,
253 .decode = yop_decode_frame,
254 .capabilities = CODEC_CAP_DR1,