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"
31 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");
92 avctx->pix_fmt = PIX_FMT_PAL8;
94 s->num_pal_colors = avctx->extradata[0];
95 s->first_color[0] = avctx->extradata[1];
96 s->first_color[1] = avctx->extradata[2];
98 if (s->num_pal_colors + s->first_color[0] > 256 ||
99 s->num_pal_colors + s->first_color[1] > 256) {
100 av_log(avctx, AV_LOG_ERROR,
101 "YOP: palette parameters invalid, header probably corrupt\n");
102 return AVERROR_INVALIDDATA;
108 static av_cold int yop_decode_close(AVCodecContext *avctx)
110 YopDecContext *s = avctx->priv_data;
111 if (s->frame.data[0])
112 avctx->release_buffer(avctx, &s->frame);
117 * Paint a macroblock using the pattern in paint_lut.
118 * @param s codec context
119 * @param tag the tag that was in the nibble
121 static void yop_paint_block(YopDecContext *s, int tag)
123 s->dstptr[0] = s->srcptr[0];
124 s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
125 s->dstptr[s->frame.linesize[0]] = s->srcptr[paint_lut[tag][1]];
126 s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]];
128 // The number of src bytes consumed is in the last part of the lut entry.
129 s->srcptr += paint_lut[tag][3];
133 * Copy a previously painted macroblock to the current_block.
134 * @param copy_tag the tag that was in the nibble
136 static int yop_copy_previous_block(YopDecContext *s, int copy_tag)
140 // Calculate position for the copy source
141 bufptr = s->dstptr + motion_vector[copy_tag][0] +
142 s->frame.linesize[0] * motion_vector[copy_tag][1];
143 if (bufptr < s->dstbuf) {
144 av_log(s->avctx, AV_LOG_ERROR,
145 "YOP: cannot decode, file probably corrupt\n");
146 return AVERROR_INVALIDDATA;
149 s->dstptr[0] = bufptr[0];
150 s->dstptr[1] = bufptr[1];
151 s->dstptr[s->frame.linesize[0]] = bufptr[s->frame.linesize[0]];
152 s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1];
158 * Return the next nibble in sequence, consuming a new byte on the input
161 static uint8_t yop_get_next_nibble(YopDecContext *s)
166 ret = *s->low_nibble & 0xf;
167 s->low_nibble = NULL;
169 s->low_nibble = s->srcptr++;
170 ret = *s->low_nibble >> 4;
176 * Take s->dstptr to the next macroblock in sequence.
178 static void yop_next_macroblock(YopDecContext *s)
180 // If we are advancing to the next row of macroblocks
181 if (s->row_pos == s->frame.linesize[0] - 2) {
182 s->dstptr += s->frame.linesize[0];
190 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
193 YopDecContext *s = avctx->priv_data;
194 int tag, firstcolor, is_odd_frame;
198 if (s->frame.data[0])
199 avctx->release_buffer(avctx, &s->frame);
201 ret = avctx->get_buffer(avctx, &s->frame);
203 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
207 s->frame.linesize[0] = avctx->width;
209 s->dstbuf = s->frame.data[0];
210 s->dstptr = s->frame.data[0];
211 s->srcptr = avpkt->data + 4;
213 s->low_nibble = NULL;
215 is_odd_frame = avpkt->data[0];
216 firstcolor = s->first_color[is_odd_frame];
217 palette = (uint32_t *)s->frame.data[1];
219 for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3)
220 palette[i + firstcolor] = (s->srcptr[0] << 18) |
221 (s->srcptr[1] << 10) |
224 s->frame.palette_has_changed = 1;
226 while (s->dstptr - s->dstbuf <
227 avctx->width * avctx->height &&
228 s->srcptr - avpkt->data < avpkt->size) {
230 tag = yop_get_next_nibble(s);
233 yop_paint_block(s, tag);
235 tag = yop_get_next_nibble(s);
236 ret = yop_copy_previous_block(s, tag);
238 avctx->release_buffer(avctx, &s->frame);
242 yop_next_macroblock(s);
245 *data_size = sizeof(AVFrame);
246 *(AVFrame *) data = s->frame;
250 AVCodec ff_yop_decoder = {
252 .type = AVMEDIA_TYPE_VIDEO,
253 .id = AV_CODEC_ID_YOP,
254 .priv_data_size = sizeof(YopDecContext),
255 .init = yop_decode_init,
256 .close = yop_decode_close,
257 .decode = yop_decode_frame,
258 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),