/* * Autodesc RLE Decoder * Copyright (C) 2005 the ffmpeg project * * 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 */ /** * @file aasc.c * Autodesc RLE Video Decoder by Konstantin Shishkov */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "avcodec.h" #include "dsputil.h" typedef struct AascContext { AVCodecContext *avctx; AVFrame frame; } AascContext; #define FETCH_NEXT_STREAM_BYTE() \ if (stream_ptr >= buf_size) \ { \ av_log(s->avctx, AV_LOG_ERROR, " AASC: stream ptr just went out of bounds (fetch)\n"); \ break; \ } \ stream_byte = buf[stream_ptr++]; static int aasc_decode_init(AVCodecContext *avctx) { AascContext *s = avctx->priv_data; s->avctx = avctx; avctx->pix_fmt = PIX_FMT_BGR24; s->frame.data[0] = NULL; return 0; } static int aasc_decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size) { AascContext *s = avctx->priv_data; int stream_ptr = 4; unsigned char rle_code; unsigned char stream_byte; int pixel_ptr = 0; int row_dec, row_ptr; int frame_size; int i; s->frame.reference = 1; s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE; if (avctx->reget_buffer(avctx, &s->frame)) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return -1; } row_dec = s->frame.linesize[0]; row_ptr = (s->avctx->height - 1) * row_dec; frame_size = row_dec * s->avctx->height; while (row_ptr >= 0) { FETCH_NEXT_STREAM_BYTE(); rle_code = stream_byte; if (rle_code == 0) { /* fetch the next byte to see how to handle escape code */ FETCH_NEXT_STREAM_BYTE(); if (stream_byte == 0) { /* line is done, goto the next one */ row_ptr -= row_dec; pixel_ptr = 0; } else if (stream_byte == 1) { /* decode is done */ break; } else if (stream_byte == 2) { /* reposition frame decode coordinates */ FETCH_NEXT_STREAM_BYTE(); pixel_ptr += stream_byte; FETCH_NEXT_STREAM_BYTE(); row_ptr -= stream_byte * row_dec; } else { /* copy pixels from encoded stream */ if ((pixel_ptr + stream_byte > avctx->width * 3) || (row_ptr < 0)) { av_log(s->avctx, AV_LOG_ERROR, " AASC: frame ptr just went out of bounds (copy1)\n"); break; } rle_code = stream_byte; if (stream_ptr + rle_code > buf_size) { av_log(s->avctx, AV_LOG_ERROR, " AASC: stream ptr just went out of bounds (copy2)\n"); break; } for (i = 0; i < rle_code; i++) { FETCH_NEXT_STREAM_BYTE(); s->frame.data[0][row_ptr + pixel_ptr] = stream_byte; pixel_ptr++; } if (rle_code & 1) stream_ptr++; } } else { /* decode a run of data */ if ((pixel_ptr + rle_code > avctx->width * 3) || (row_ptr < 0)) { av_log(s->avctx, AV_LOG_ERROR, " AASC: frame ptr just went out of bounds (run1)\n"); break; } FETCH_NEXT_STREAM_BYTE(); while(rle_code--) { s->frame.data[0][row_ptr + pixel_ptr] = stream_byte; pixel_ptr++; } } } /* one last sanity check on the way out */ if (stream_ptr < buf_size) av_log(s->avctx, AV_LOG_ERROR, " AASC: ended frame decode with bytes left over (%d < %d)\n", stream_ptr, buf_size); *data_size = sizeof(AVFrame); *(AVFrame*)data = s->frame; /* report that the buffer was completely consumed */ return buf_size; } static int aasc_decode_end(AVCodecContext *avctx) { AascContext *s = avctx->priv_data; /* release the last frame */ if (s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); return 0; } AVCodec aasc_decoder = { "aasc", CODEC_TYPE_VIDEO, CODEC_ID_AASC, sizeof(AascContext), aasc_decode_init, NULL, aasc_decode_end, aasc_decode_frame, CODEC_CAP_DR1, };