From 148bcae98c7227cfe0aac74841b0888bd456332a Mon Sep 17 00:00:00 2001 From: Mohamed Naufal Date: Mon, 29 Mar 2010 22:17:01 +0000 Subject: Implement YOP demuxer and video decoder. Patch by Mohamed Naufal gmailify(naufal11). Originally committed as revision 22724 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/yop.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 260 insertions(+) create mode 100644 libavcodec/yop.c (limited to 'libavcodec/yop.c') diff --git a/libavcodec/yop.c b/libavcodec/yop.c new file mode 100644 index 0000000000..235e5c9658 --- /dev/null +++ b/libavcodec/yop.c @@ -0,0 +1,260 @@ +/** + * @file libavcodec/yop.c + * Psygnosis YOP decoder + * + * Copyright (C) 2010 Mohamed Naufal Basheer + * derived from the code by + * Copyright (C) 2009 Thomas P. Higdon + * + * This file is part of FFmpeg. + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libavutil/intreadwrite.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 || + avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 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; +} + +/** + * Paints 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]; +} + +/** + * Copies 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; +} + +/** + * Returns 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; +} + +/** + * Takes 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 yop_decoder = { + "yop", + CODEC_TYPE_VIDEO, + CODEC_ID_YOP, + sizeof(YopDecContext), + yop_decode_init, + NULL, + yop_decode_close, + yop_decode_frame, + .long_name = NULL_IF_CONFIG_SMALL("Psygnosis YOP Video"), +}; -- cgit v1.2.3