/* * Psygnosis YOP decoder * * Copyright (C) 2010 Mohamed Naufal Basheer <naufal11@gmail.com> * derived from the code by * Copyright (C) 2009 Thomas P. Higdon <thomas.p.higdon@gmail.com> * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/intreadwrite.h" #include "libavutil/imgutils.h" #include "avcodec.h" #include "get_bits.h" typedef struct YopDecContext { AVFrame frame; AVCodecContext *avctx; int num_pal_colors; int first_color[2]; int frame_data_length; int row_pos; uint8_t *low_nibble; uint8_t *srcptr; uint8_t *dstptr; uint8_t *dstbuf; } YopDecContext; // These tables are taken directly from: // http://wiki.multimedia.cx/index.php?title=Psygnosis_YOP /** * Lookup table for painting macroblocks. Bytes 0-2 of each entry contain * the macroblock positions to be painted (taken as (0, B0, B1, B2)). * Byte 3 contains the number of bytes consumed on the input, * equal to max(bytes 0-2) + 1. */ static const uint8_t paint_lut[15][4] = {{1, 2, 3, 4}, {1, 2, 0, 3}, {1, 2, 1, 3}, {1, 2, 2, 3}, {1, 0, 2, 3}, {1, 0, 0, 2}, {1, 0, 1, 2}, {1, 1, 2, 3}, {0, 1, 2, 3}, {0, 1, 0, 2}, {1, 1, 0, 2}, {0, 1, 1, 2}, {0, 0, 1, 2}, {0, 0, 0, 1}, {1, 1, 1, 2}, }; /** * Lookup table for copying macroblocks. Each entry contains the respective * x and y pixel offset for the copy source. */ static const int8_t motion_vector[16][2] = {{-4, -4}, {-2, -4}, { 0, -4}, { 2, -4}, {-4, -2}, {-4, 0}, {-3, -3}, {-1, -3}, { 1, -3}, { 3, -3}, {-3, -1}, {-2, -2}, { 0, -2}, { 2, -2}, { 4, -2}, {-2, 0}, }; static av_cold int yop_decode_init(AVCodecContext *avctx) { YopDecContext *s = avctx->priv_data; s->avctx = avctx; if (avctx->width & 1 || avctx->height & 1 || av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) { av_log(avctx, AV_LOG_ERROR, "YOP has invalid dimensions\n"); return -1; } avctx->pix_fmt = PIX_FMT_PAL8; s->num_pal_colors = avctx->extradata[0]; s->first_color[0] = avctx->extradata[1]; s->first_color[1] = avctx->extradata[2]; if (s->num_pal_colors + s->first_color[0] > 256 || s->num_pal_colors + s->first_color[1] > 256) { av_log(avctx, AV_LOG_ERROR, "YOP: palette parameters invalid, header probably corrupt\n"); return AVERROR_INVALIDDATA; } return 0; } static av_cold int yop_decode_close(AVCodecContext *avctx) { YopDecContext *s = avctx->priv_data; if (s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); return 0; } /** * Paint a macroblock using the pattern in paint_lut. * @param s codec context * @param tag the tag that was in the nibble */ static void yop_paint_block(YopDecContext *s, int tag) { s->dstptr[0] = s->srcptr[0]; s->dstptr[1] = s->srcptr[paint_lut[tag][0]]; s->dstptr[s->frame.linesize[0]] = s->srcptr[paint_lut[tag][1]]; s->dstptr[s->frame.linesize[0] + 1] = s->srcptr[paint_lut[tag][2]]; // The number of src bytes consumed is in the last part of the lut entry. s->srcptr += paint_lut[tag][3]; } /** * Copy a previously painted macroblock to the current_block. * @param copy_tag the tag that was in the nibble */ static int yop_copy_previous_block(YopDecContext *s, int copy_tag) { uint8_t *bufptr; // Calculate position for the copy source bufptr = s->dstptr + motion_vector[copy_tag][0] + s->frame.linesize[0] * motion_vector[copy_tag][1]; if (bufptr < s->dstbuf) { av_log(s->avctx, AV_LOG_ERROR, "YOP: cannot decode, file probably corrupt\n"); return AVERROR_INVALIDDATA; } s->dstptr[0] = bufptr[0]; s->dstptr[1] = bufptr[1]; s->dstptr[s->frame.linesize[0]] = bufptr[s->frame.linesize[0]]; s->dstptr[s->frame.linesize[0] + 1] = bufptr[s->frame.linesize[0] + 1]; return 0; } /** * Return the next nibble in sequence, consuming a new byte on the input * only if necessary. */ static uint8_t yop_get_next_nibble(YopDecContext *s) { int ret; if (s->low_nibble) { ret = *s->low_nibble & 0xf; s->low_nibble = NULL; }else { s->low_nibble = s->srcptr++; ret = *s->low_nibble >> 4; } return ret; } /** * Take s->dstptr to the next macroblock in sequence. */ static void yop_next_macroblock(YopDecContext *s) { // If we are advancing to the next row of macroblocks if (s->row_pos == s->frame.linesize[0] - 2) { s->dstptr += s->frame.linesize[0]; s->row_pos = 0; }else { s->row_pos += 2; } s->dstptr += 2; } static int yop_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { YopDecContext *s = avctx->priv_data; int tag, firstcolor, is_odd_frame; int ret, i; uint32_t *palette; if (s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); ret = avctx->get_buffer(avctx, &s->frame); if (ret < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } s->frame.linesize[0] = avctx->width; s->dstbuf = s->frame.data[0]; s->dstptr = s->frame.data[0]; s->srcptr = avpkt->data + 4; s->row_pos = 0; s->low_nibble = NULL; is_odd_frame = avpkt->data[0]; firstcolor = s->first_color[is_odd_frame]; palette = (uint32_t *)s->frame.data[1]; for (i = 0; i < s->num_pal_colors; i++, s->srcptr += 3) palette[i + firstcolor] = (s->srcptr[0] << 18) | (s->srcptr[1] << 10) | (s->srcptr[2] << 2); s->frame.palette_has_changed = 1; while (s->dstptr - s->dstbuf < avctx->width * avctx->height && s->srcptr - avpkt->data < avpkt->size) { tag = yop_get_next_nibble(s); if (tag != 0xf) { yop_paint_block(s, tag); }else { tag = yop_get_next_nibble(s); ret = yop_copy_previous_block(s, tag); if (ret < 0) { avctx->release_buffer(avctx, &s->frame); return ret; } } yop_next_macroblock(s); } *data_size = sizeof(AVFrame); *(AVFrame *) data = s->frame; return avpkt->size; } AVCodec ff_yop_decoder = { .name = "yop", .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_YOP, .priv_data_size = sizeof(YopDecContext), .init = yop_decode_init, .close = yop_decode_close, .decode = yop_decode_frame, .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"), };