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 FFmpeg.
10 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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 if (!avctx->extradata) {
93 av_log(avctx, AV_LOG_ERROR, "extradata missing\n");
94 return AVERROR_INVALIDDATA;
97 avctx->pix_fmt = PIX_FMT_PAL8;
99 avcodec_get_frame_defaults(&s->frame);
100 s->num_pal_colors = avctx->extradata[0];
101 s->first_color[0] = avctx->extradata[1];
102 s->first_color[1] = avctx->extradata[2];
104 if (s->num_pal_colors + s->first_color[0] > 256 ||
105 s->num_pal_colors + s->first_color[1] > 256) {
106 av_log(avctx, AV_LOG_ERROR,
107 "YOP: palette parameters invalid, header probably corrupt\n");
108 return AVERROR_INVALIDDATA;
114 static av_cold int yop_decode_close(AVCodecContext *avctx)
116 YopDecContext *s = avctx->priv_data;
117 if (s->frame.data[0])
118 avctx->release_buffer(avctx, &s->frame);
123 * Paint a macroblock using the pattern in paint_lut.
124 * @param s codec context
125 * @param tag the tag that was in the nibble
127 static void yop_paint_block(YopDecContext *s, int tag)
129 s->dstptr[0] = s->srcptr[0];
130 s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
131 s->dstptr[s->frame.linesize[0]] = s->srcptr[paint_lut[tag][1]];
132 s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]];
134 // The number of src bytes consumed is in the last part of the lut entry.
135 s->srcptr += paint_lut[tag][3];
139 * Copy a previously painted macroblock to the current_block.
140 * @param copy_tag the tag that was in the nibble
142 static int yop_copy_previous_block(YopDecContext *s, int copy_tag)
146 // Calculate position for the copy source
147 bufptr = s->dstptr + motion_vector[copy_tag][0] +
148 s->frame.linesize[0] * motion_vector[copy_tag][1];
149 if (bufptr < s->dstbuf) {
150 av_log(s->avctx, AV_LOG_ERROR,
151 "YOP: cannot decode, file probably corrupt\n");
152 return AVERROR_INVALIDDATA;
155 s->dstptr[0] = bufptr[0];
156 s->dstptr[1] = bufptr[1];
157 s->dstptr[s->frame.linesize[0]] = bufptr[s->frame.linesize[0]];
158 s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1];
164 * Return the next nibble in sequence, consuming a new byte on the input
167 static uint8_t yop_get_next_nibble(YopDecContext *s)
172 ret = *s->low_nibble & 0xf;
173 s->low_nibble = NULL;
175 s->low_nibble = s->srcptr++;
176 ret = *s->low_nibble >> 4;
182 * Take s->dstptr to the next macroblock in sequence.
184 static void yop_next_macroblock(YopDecContext *s)
186 // If we are advancing to the next row of macroblocks
187 if (s->row_pos == s->frame.linesize[0] - 2) {
188 s->dstptr += s->frame.linesize[0];
196 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
199 YopDecContext *s = avctx->priv_data;
200 int tag, firstcolor, is_odd_frame;
204 if (s->frame.data[0])
205 avctx->release_buffer(avctx, &s->frame);
207 if (avpkt->size < 4 + 3*s->num_pal_colors) {
208 av_log(avctx, AV_LOG_ERROR, "packet of size %d too small\n", avpkt->size);
209 return AVERROR_INVALIDDATA;
212 ret = avctx->get_buffer(avctx, &s->frame);
214 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
218 s->frame.linesize[0] = avctx->width;
220 s->dstbuf = s->frame.data[0];
221 s->dstptr = s->frame.data[0];
222 s->srcptr = avpkt->data + 4;
224 s->low_nibble = NULL;
226 is_odd_frame = avpkt->data[0];
228 av_log(avctx, AV_LOG_ERROR, "frame is too odd %d\n", is_odd_frame);
229 return AVERROR_INVALIDDATA;
231 firstcolor = s->first_color[is_odd_frame];
232 palette = (uint32_t *)s->frame.data[1];
234 for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3) {
235 palette[i + firstcolor] = (s->srcptr[0] << 18) |
236 (s->srcptr[1] << 10) |
238 palette[i + firstcolor] |= 0xFF << 24 |
239 (palette[i + firstcolor] >> 6) & 0x30303;
242 s->frame.palette_has_changed = 1;
244 while (s->dstptr - s->dstbuf <
245 avctx->width * avctx->height &&
246 s->srcptr - avpkt->data < avpkt->size) {
248 tag = yop_get_next_nibble(s);
251 yop_paint_block(s, tag);
253 tag = yop_get_next_nibble(s);
254 ret = yop_copy_previous_block(s, tag);
256 avctx->release_buffer(avctx, &s->frame);
260 yop_next_macroblock(s);
263 *data_size = sizeof(AVFrame);
264 *(AVFrame *) data = s->frame;
268 AVCodec ff_yop_decoder = {
270 .type = AVMEDIA_TYPE_VIDEO,
272 .priv_data_size = sizeof(YopDecContext),
273 .init = yop_decode_init,
274 .close = yop_decode_close,
275 .decode = yop_decode_frame,
276 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),