/* * Micrsoft RLE Video Decoder * Copyright (C) 2003 the ffmpeg project * * This library 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 of the License, or (at your option) any later version. * * This library 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 this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /** * @file msrle.c * MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net) * For more information about the MS RLE format, visit: * http://www.pcisys.net/~melanson/codecs/ * * The MS RLE decoder outputs PAL8 colorspace data. * * Note that this decoder expects the palette colors from the end of the * BITMAPINFO header passed through palctrl. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "common.h" #include "avcodec.h" #include "dsputil.h" typedef struct MsrleContext { AVCodecContext *avctx; AVFrame frame; AVFrame prev_frame; unsigned char *buf; int size; } MsrleContext; #define FETCH_NEXT_STREAM_BYTE() \ if (stream_ptr >= s->size) \ { \ printf(" MS RLE: stream ptr just went out of bounds (1)\n"); \ return; \ } \ stream_byte = s->buf[stream_ptr++]; static void msrle_decode_pal8(MsrleContext *s) { int stream_ptr = 0; unsigned char rle_code; unsigned char extra_byte; unsigned char stream_byte; int pixel_ptr = 0; int row_dec = s->frame.linesize[0]; int row_ptr = (s->avctx->height - 1) * row_dec; int 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 */ return; } 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 ((row_ptr + pixel_ptr + stream_byte > frame_size) || (row_ptr < 0)) { printf(" MS RLE: frame ptr just went out of bounds (1)\n"); return; } rle_code = stream_byte; extra_byte = stream_byte & 0x01; if (stream_ptr + rle_code + extra_byte > s->size) { printf(" MS RLE: stream ptr just went out of bounds (2)\n"); return; } while (rle_code--) { FETCH_NEXT_STREAM_BYTE(); s->frame.data[0][row_ptr + pixel_ptr] = stream_byte; pixel_ptr++; } /* if the RLE code is odd, skip a byte in the stream */ if (extra_byte) stream_ptr++; } } else { /* decode a run of data */ if ((row_ptr + pixel_ptr + stream_byte > frame_size) || (row_ptr < 0)) { printf(" MS RLE: frame ptr just went out of bounds (2)\n"); return; } FETCH_NEXT_STREAM_BYTE(); while(rle_code--) { s->frame.data[0][row_ptr + pixel_ptr] = stream_byte; pixel_ptr++; } } } /* make the palette available */ memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE); if (s->avctx->palctrl->palette_changed) { s->frame.palette_has_changed = 1; s->avctx->palctrl->palette_changed = 0; } /* one last sanity check on the way out */ if (stream_ptr < s->size) printf(" MS RLE: ended frame decode with bytes left over (%d < %d)\n", stream_ptr, s->size); } static int msrle_decode_init(AVCodecContext *avctx) { MsrleContext *s = (MsrleContext *)avctx->priv_data; s->avctx = avctx; avctx->pix_fmt = PIX_FMT_PAL8; avctx->has_b_frames = 0; s->frame.data[0] = s->prev_frame.data[0] = NULL; return 0; } static int msrle_decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size) { MsrleContext *s = (MsrleContext *)avctx->priv_data; s->buf = buf; s->size = buf_size; s->frame.reference = 1; if (avctx->get_buffer(avctx, &s->frame)) { printf (" MS RLE: get_buffer() failed\n"); return -1; } if (s->prev_frame.data[0] && (s->frame.linesize[0] != s->prev_frame.linesize[0])) printf (" MS RLE: Buffer linesize changed: current %u, previous %u.\n" " Expect wrong image and/or crash!\n", s->frame.linesize[0], s->prev_frame.linesize[0]); /* grossly inefficient, but...oh well */ if (s->prev_frame.data[0] != NULL) memcpy(s->frame.data[0], s->prev_frame.data[0], s->frame.linesize[0] * s->avctx->height); msrle_decode_pal8(s); if (s->prev_frame.data[0]) avctx->release_buffer(avctx, &s->prev_frame); /* shuffle frames */ s->prev_frame = s->frame; *data_size = sizeof(AVFrame); *(AVFrame*)data = s->frame; /* report that the buffer was completely consumed */ return buf_size; } static int msrle_decode_end(AVCodecContext *avctx) { MsrleContext *s = (MsrleContext *)avctx->priv_data; /* release the last frame */ if (s->prev_frame.data[0]) avctx->release_buffer(avctx, &s->prev_frame); return 0; } AVCodec msrle_decoder = { "msrle", CODEC_TYPE_VIDEO, CODEC_ID_MSRLE, sizeof(MsrleContext), msrle_decode_init, NULL, msrle_decode_end, msrle_decode_frame, CODEC_CAP_DR1, };