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
27 #include "libavutil/imgutils.h"
28 #include "libavutil/internal.h"
29 #include "libavutil/intreadwrite.h"
34 typedef struct YopDecContext {
35 AVCodecContext *avctx;
39 int frame_data_length;
48 // These tables are taken directly from:
49 // http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP
52 * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain
53 * the macroblock positions to be painted (taken as (0, B0, B1, B2)).
54 * Byte 3 contains the number of bytes consumed on the input,
55 * equal to max(bytes 0-2) + 1.
57 static const uint8_t paint_lut[15][4] =
58 {{1, 2, 3, 4}, {1, 2, 0, 3},
59 {1, 2, 1, 3}, {1, 2, 2, 3},
60 {1, 0, 2, 3}, {1, 0, 0, 2},
61 {1, 0, 1, 2}, {1, 1, 2, 3},
62 {0, 1, 2, 3}, {0, 1, 0, 2},
63 {1, 1, 0, 2}, {0, 1, 1, 2},
64 {0, 0, 1, 2}, {0, 0, 0, 1},
69 * Lookup table for copying macroblocks. Each entry contains the respective
70 * x and y pixel offset for the copy source.
72 static const int8_t motion_vector[16][2] =
83 static av_cold int yop_decode_init(AVCodecContext *avctx)
85 YopDecContext *s = avctx->priv_data;
88 if (avctx->width & 1 || avctx->height & 1 ||
89 av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
90 av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
91 return AVERROR_INVALIDDATA;
94 if (avctx->extradata_size < 3) {
95 av_log(avctx, AV_LOG_ERROR, "Missing or incomplete extradata.\n");
96 return AVERROR_INVALIDDATA;
99 avctx->pix_fmt = AV_PIX_FMT_PAL8;
101 s->num_pal_colors = avctx->extradata[0];
102 s->first_color[0] = avctx->extradata[1];
103 s->first_color[1] = avctx->extradata[2];
105 if (s->num_pal_colors + s->first_color[0] > 256 ||
106 s->num_pal_colors + s->first_color[1] > 256) {
107 av_log(avctx, AV_LOG_ERROR,
108 "YOP: palette parameters invalid, header probably corrupt\n");
109 return AVERROR_INVALIDDATA;
116 * Paint a macroblock using the pattern in paint_lut.
117 * @param s codec context
118 * @param tag the tag that was in the nibble
120 static int yop_paint_block(YopDecContext *s, int linesize, int tag)
122 if (s->src_end - s->srcptr < paint_lut[tag][3]) {
123 av_log(s->avctx, AV_LOG_ERROR, "Packet too small.\n");
124 return AVERROR_INVALIDDATA;
127 s->dstptr[0] = s->srcptr[0];
128 s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
129 s->dstptr[linesize] = s->srcptr[paint_lut[tag][1]];
130 s->dstptr[linesize + 1] = s->srcptr[paint_lut[tag][2]];
132 // The number of src bytes consumed is in the last part of the lut entry.
133 s->srcptr += paint_lut[tag][3];
138 * Copy a previously painted macroblock to the current_block.
139 * @param copy_tag the tag that was in the nibble
141 static int yop_copy_previous_block(YopDecContext *s, int linesize, int copy_tag)
145 // Calculate position for the copy source
146 bufptr = s->dstptr + motion_vector[copy_tag][0] +
147 linesize * motion_vector[copy_tag][1];
148 if (bufptr < s->dstbuf) {
149 av_log(s->avctx, AV_LOG_ERROR,
150 "YOP: cannot decode, file probably corrupt\n");
151 return AVERROR_INVALIDDATA;
154 s->dstptr[0] = bufptr[0];
155 s->dstptr[1] = bufptr[1];
156 s->dstptr[linesize] = bufptr[linesize];
157 s->dstptr[linesize + 1] = bufptr[linesize + 1];
163 * Return the next nibble in sequence, consuming a new byte on the input
166 static uint8_t yop_get_next_nibble(YopDecContext *s)
171 ret = *s->low_nibble & 0xf;
172 s->low_nibble = NULL;
174 s->low_nibble = s->srcptr++;
175 ret = *s->low_nibble >> 4;
180 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
183 YopDecContext *s = avctx->priv_data;
184 AVFrame *frame = data;
185 int tag, firstcolor, is_odd_frame;
189 if (avpkt->size < 4 + 3 * s->num_pal_colors) {
190 av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
191 return AVERROR_INVALIDDATA;
194 ret = ff_get_buffer(avctx, frame, 0);
196 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
200 if (!avctx->frame_number)
201 memset(frame->data[1], 0, AVPALETTE_SIZE);
203 s->dstbuf = frame->data[0];
204 s->dstptr = frame->data[0];
205 s->srcptr = avpkt->data + 4;
206 s->src_end = avpkt->data + avpkt->size;
207 s->low_nibble = NULL;
209 is_odd_frame = avpkt->data[0];
210 firstcolor = s->first_color[is_odd_frame];
211 palette = (uint32_t *)frame->data[1];
213 for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3)
214 palette[i + firstcolor] = (s->srcptr[0] << 18) |
215 (s->srcptr[1] << 10) |
218 frame->palette_has_changed = 1;
220 for (y = 0; y < avctx->height; y += 2) {
221 for (x = 0; x < avctx->width; x += 2) {
222 if (s->srcptr - avpkt->data >= avpkt->size) {
223 av_log(avctx, AV_LOG_ERROR, "Packet too small.\n");
224 return AVERROR_INVALIDDATA;
227 tag = yop_get_next_nibble(s);
230 ret = yop_paint_block(s, frame->linesize[0], tag);
234 tag = yop_get_next_nibble(s);
235 ret = yop_copy_previous_block(s, frame->linesize[0], tag);
241 s->dstptr += 2*frame->linesize[0] - x;
248 AVCodec ff_yop_decoder = {
250 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
251 .type = AVMEDIA_TYPE_VIDEO,
252 .id = AV_CODEC_ID_YOP,
253 .priv_data_size = sizeof(YopDecContext),
254 .init = yop_decode_init,
255 .decode = yop_decode_frame,
256 .capabilities = AV_CODEC_CAP_DR1,