3 * Psygnosis YOP decoder
5 * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com>
6 * derived from the code by
7 * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com>
9 * This file is part of FFmpeg.
11 * FFmpeg is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
16 * FFmpeg is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with FFmpeg; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/imgutils.h"
32 typedef struct YopDecContext {
34 AVCodecContext *avctx;
38 int frame_data_length;
47 // These tables are taken directly from:
48 // http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP
51 * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain
52 * the macroblock positions to be painted (taken as (0, B0, B1, B2)).
53 * Byte 3 contains the number of bytes consumed on the input,
54 * equal to max(bytes 0-2) + 1.
56 static const uint8_t paint_lut[15][4] =
57 {{1, 2, 3, 4}, {1, 2, 0, 3},
58 {1, 2, 1, 3}, {1, 2, 2, 3},
59 {1, 0, 2, 3}, {1, 0, 0, 2},
60 {1, 0, 1, 2}, {1, 1, 2, 3},
61 {0, 1, 2, 3}, {0, 1, 0, 2},
62 {1, 1, 0, 2}, {0, 1, 1, 2},
63 {0, 0, 1, 2}, {0, 0, 0, 1},
68 * Lookup table for copying macroblocks. Each entry contains the respective
69 * x and y pixel offset for the copy source.
71 static const int8_t motion_vector[16][2] =
82 static av_cold int yop_decode_init(AVCodecContext *avctx)
84 YopDecContext *s = avctx->priv_data;
87 if (avctx->width & 1 || avctx->height & 1 ||
88 av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
89 av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
93 avctx->pix_fmt = PIX_FMT_PAL8;
95 s->num_pal_colors = avctx->extradata[0];
96 s->first_color[0] = avctx->extradata[1];
97 s->first_color[1] = avctx->extradata[2];
99 if (s->num_pal_colors + s->first_color[0] > 256 ||
100 s->num_pal_colors + s->first_color[1] > 256) {
101 av_log(avctx, AV_LOG_ERROR,
102 "YOP: palette parameters invalid, header probably corrupt\n");
103 return AVERROR_INVALIDDATA;
109 static av_cold int yop_decode_close(AVCodecContext *avctx)
111 YopDecContext *s = avctx->priv_data;
112 if (s->frame.data[0])
113 avctx->release_buffer(avctx, &s->frame);
118 * Paint a macroblock using the pattern in paint_lut.
119 * @param s codec context
120 * @param tag the tag that was in the nibble
122 static void yop_paint_block(YopDecContext *s, int tag)
124 s->dstptr[0] = s->srcptr[0];
125 s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
126 s->dstptr[s->frame.linesize[0]] = s->srcptr[paint_lut[tag][1]];
127 s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]];
129 // The number of src bytes consumed is in the last part of the lut entry.
130 s->srcptr += paint_lut[tag][3];
134 * Copy a previously painted macroblock to the current_block.
135 * @param copy_tag the tag that was in the nibble
137 static int yop_copy_previous_block(YopDecContext *s, int copy_tag)
141 // Calculate position for the copy source
142 bufptr = s->dstptr + motion_vector[copy_tag][0] +
143 s->frame.linesize[0] * motion_vector[copy_tag][1];
144 if (bufptr < s->dstbuf) {
145 av_log(s->avctx, AV_LOG_ERROR,
146 "YOP: cannot decode, file probably corrupt\n");
147 return AVERROR_INVALIDDATA;
150 s->dstptr[0] = bufptr[0];
151 s->dstptr[1] = bufptr[1];
152 s->dstptr[s->frame.linesize[0]] = bufptr[s->frame.linesize[0]];
153 s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1];
159 * Return the next nibble in sequence, consuming a new byte on the input
162 static uint8_t yop_get_next_nibble(YopDecContext *s)
167 ret = *s->low_nibble & 0xf;
168 s->low_nibble = NULL;
170 s->low_nibble = s->srcptr++;
171 ret = *s->low_nibble >> 4;
177 * Take s->dstptr to the next macroblock in sequence.
179 static void yop_next_macroblock(YopDecContext *s)
181 // If we are advancing to the next row of macroblocks
182 if (s->row_pos == s->frame.linesize[0] - 2) {
183 s->dstptr += s->frame.linesize[0];
191 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
194 YopDecContext *s = avctx->priv_data;
195 int tag, firstcolor, is_odd_frame;
199 if (s->frame.data[0])
200 avctx->release_buffer(avctx, &s->frame);
202 ret = avctx->get_buffer(avctx, &s->frame);
204 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
208 s->frame.linesize[0] = avctx->width;
210 s->dstbuf = s->frame.data[0];
211 s->dstptr = s->frame.data[0];
212 s->srcptr = avpkt->data + 4;
214 s->low_nibble = NULL;
216 is_odd_frame = avpkt->data[0];
217 firstcolor = s->first_color[is_odd_frame];
218 palette = (uint32_t *)s->frame.data[1];
220 for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3)
221 palette[i + firstcolor] = (s->srcptr[0] << 18) |
222 (s->srcptr[1] << 10) |
225 s->frame.palette_has_changed = 1;
227 while (s->dstptr - s->dstbuf <
228 avctx->width * avctx->height &&
229 s->srcptr - avpkt->data < avpkt->size) {
231 tag = yop_get_next_nibble(s);
234 yop_paint_block(s, tag);
236 tag = yop_get_next_nibble(s);
237 ret = yop_copy_previous_block(s, tag);
239 avctx->release_buffer(avctx, &s->frame);
243 yop_next_macroblock(s);
246 *data_size = sizeof(AVFrame);
247 *(AVFrame *) data = s->frame;
251 AVCodec ff_yop_decoder = {
255 sizeof(YopDecContext),
260 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),