00001
00026 #include "libavutil/intreadwrite.h"
00027
00028 #include "avcodec.h"
00029 #include "get_bits.h"
00030
00031 typedef struct YopDecContext {
00032 AVFrame frame;
00033 AVCodecContext *avctx;
00034
00035 int num_pal_colors;
00036 int first_color[2];
00037 int frame_data_length;
00038 int row_pos;
00039
00040 uint8_t *low_nibble;
00041 uint8_t *srcptr;
00042 uint8_t *dstptr;
00043 uint8_t *dstbuf;
00044 } YopDecContext;
00045
00046
00047
00048
00055 static const uint8_t paint_lut[15][4] =
00056 {{1, 2, 3, 4}, {1, 2, 0, 3},
00057 {1, 2, 1, 3}, {1, 2, 2, 3},
00058 {1, 0, 2, 3}, {1, 0, 0, 2},
00059 {1, 0, 1, 2}, {1, 1, 2, 3},
00060 {0, 1, 2, 3}, {0, 1, 0, 2},
00061 {1, 1, 0, 2}, {0, 1, 1, 2},
00062 {0, 0, 1, 2}, {0, 0, 0, 1},
00063 {1, 1, 1, 2},
00064 };
00065
00070 static const int8_t motion_vector[16][2] =
00071 {{-4, -4}, {-2, -4},
00072 { 0, -4}, { 2, -4},
00073 {-4, -2}, {-4, 0},
00074 {-3, -3}, {-1, -3},
00075 { 1, -3}, { 3, -3},
00076 {-3, -1}, {-2, -2},
00077 { 0, -2}, { 2, -2},
00078 { 4, -2}, {-2, 0},
00079 };
00080
00081 static av_cold int yop_decode_init(AVCodecContext *avctx)
00082 {
00083 YopDecContext *s = avctx->priv_data;
00084 s->avctx = avctx;
00085
00086 if (avctx->width & 1 || avctx->height & 1 ||
00087 avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
00088 av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n");
00089 return -1;
00090 }
00091
00092 avctx->pix_fmt = PIX_FMT_PAL8;
00093
00094 s->num_pal_colors = avctx->extradata[0];
00095 s->first_color[0] = avctx->extradata[1];
00096 s->first_color[1] = avctx->extradata[2];
00097
00098 if (s->num_pal_colors + s->first_color[0] > 256 ||
00099 s->num_pal_colors + s->first_color[1] > 256) {
00100 av_log(avctx, AV_LOG_ERROR,
00101 "YOP: palette parameters invalid, header probably corrupt\n");
00102 return AVERROR_INVALIDDATA;
00103 }
00104
00105 return 0;
00106 }
00107
00108 static av_cold int yop_decode_close(AVCodecContext *avctx)
00109 {
00110 YopDecContext *s = avctx->priv_data;
00111 if (s->frame.data[0])
00112 avctx->release_buffer(avctx, &s->frame);
00113 return 0;
00114 }
00115
00121 static void yop_paint_block(YopDecContext *s, int tag)
00122 {
00123 s->dstptr[0] = s->srcptr[0];
00124 s->dstptr[1] = s->srcptr[paint_lut[tag][0]];
00125 s->dstptr[s->frame.linesize[0]] = s->srcptr[paint_lut[tag][1]];
00126 s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]];
00127
00128
00129 s->srcptr += paint_lut[tag][3];
00130 }
00131
00136 static int yop_copy_previous_block(YopDecContext *s, int copy_tag)
00137 {
00138 uint8_t *bufptr;
00139
00140
00141 bufptr = s->dstptr + motion_vector[copy_tag][0] +
00142 s->frame.linesize[0] * motion_vector[copy_tag][1];
00143 if (bufptr < s->dstbuf) {
00144 av_log(s->avctx, AV_LOG_ERROR,
00145 "YOP: cannot decode, file probably corrupt\n");
00146 return AVERROR_INVALIDDATA;
00147 }
00148
00149 s->dstptr[0] = bufptr[0];
00150 s->dstptr[1] = bufptr[1];
00151 s->dstptr[s->frame.linesize[0]] = bufptr[s->frame.linesize[0]];
00152 s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1];
00153
00154 return 0;
00155 }
00156
00161 static uint8_t yop_get_next_nibble(YopDecContext *s)
00162 {
00163 int ret;
00164
00165 if (s->low_nibble) {
00166 ret = *s->low_nibble & 0xf;
00167 s->low_nibble = NULL;
00168 }else {
00169 s->low_nibble = s->srcptr++;
00170 ret = *s->low_nibble >> 4;
00171 }
00172 return ret;
00173 }
00174
00178 static void yop_next_macroblock(YopDecContext *s)
00179 {
00180
00181 if (s->row_pos == s->frame.linesize[0] - 2) {
00182 s->dstptr += s->frame.linesize[0];
00183 s->row_pos = 0;
00184 }else {
00185 s->row_pos += 2;
00186 }
00187 s->dstptr += 2;
00188 }
00189
00190 static int yop_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
00191 AVPacket *avpkt)
00192 {
00193 YopDecContext *s = avctx->priv_data;
00194 int tag, firstcolor, is_odd_frame;
00195 int ret, i;
00196 uint32_t *palette;
00197
00198 if (s->frame.data[0])
00199 avctx->release_buffer(avctx, &s->frame);
00200
00201 ret = avctx->get_buffer(avctx, &s->frame);
00202 if (ret < 0) {
00203 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00204 return ret;
00205 }
00206
00207 s->frame.linesize[0] = avctx->width;
00208
00209 s->dstbuf = s->frame.data[0];
00210 s->dstptr = s->frame.data[0];
00211 s->srcptr = avpkt->data + 4;
00212 s->row_pos = 0;
00213 s->low_nibble = NULL;
00214
00215 is_odd_frame = avpkt->data[0];
00216 firstcolor = s->first_color[is_odd_frame];
00217 palette = (uint32_t *)s->frame.data[1];
00218
00219 for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3)
00220 palette[i + firstcolor] = (s->srcptr[0] << 18) |
00221 (s->srcptr[1] << 10) |
00222 (s->srcptr[2] << 2);
00223
00224 s->frame.palette_has_changed = 1;
00225
00226 while (s->dstptr - s->dstbuf <
00227 avctx->width * avctx->height &&
00228 s->srcptr - avpkt->data < avpkt->size) {
00229
00230 tag = yop_get_next_nibble(s);
00231
00232 if (tag != 0xf) {
00233 yop_paint_block(s, tag);
00234 }else {
00235 tag = yop_get_next_nibble(s);
00236 ret = yop_copy_previous_block(s, tag);
00237 if (ret < 0) {
00238 avctx->release_buffer(avctx, &s->frame);
00239 return ret;
00240 }
00241 }
00242 yop_next_macroblock(s);
00243 }
00244
00245 *data_size = sizeof(AVFrame);
00246 *(AVFrame *) data = s->frame;
00247 return avpkt->size;
00248 }
00249
00250 AVCodec yop_decoder = {
00251 "yop",
00252 AVMEDIA_TYPE_VIDEO,
00253 CODEC_ID_YOP,
00254 sizeof(YopDecContext),
00255 yop_decode_init,
00256 NULL,
00257 yop_decode_close,
00258 yop_decode_frame,
00259 .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"),
00260 };