/* * 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; unsigned char *buf; int size; } MsrleContext; #define FETCH_NEXT_STREAM_BYTE() \ if (stream_ptr >= s->size) \ { \ av_log(s->avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \ return; \ } \ stream_byte = s->buf[stream_ptr++]; static void msrle_decode_pal4(MsrleContext *s) { int stream_ptr = 0; unsigned char rle_code; unsigned char extra_byte, odd_pixel; 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; int i; /* 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; } 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 odd_pixel = stream_byte & 1; rle_code = (stream_byte + 1) / 2; extra_byte = rle_code & 0x01; if ((row_ptr + pixel_ptr + stream_byte > frame_size) || (row_ptr < 0)) { av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n"); return; } for (i = 0; i < rle_code; i++) { if (pixel_ptr >= s->avctx->width) break; FETCH_NEXT_STREAM_BYTE(); s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4; pixel_ptr++; if (i + 1 == rle_code && odd_pixel) break; if (pixel_ptr >= s->avctx->width) break; s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F; 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)) { av_log(s->avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n"); return; } FETCH_NEXT_STREAM_BYTE(); for (i = 0; i < rle_code; i++) { if (pixel_ptr >= s->avctx->width) break; if ((i & 1) == 0) s->frame.data[0][row_ptr + pixel_ptr] = stream_byte >> 4; else s->frame.data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F; pixel_ptr++; } } } /* one last sanity check on the way out */ if (stream_ptr < s->size) av_log(s->avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n", stream_ptr, s->size); } 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; /* 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; } 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)) { av_log(s->avctx, AV_LOG_ERROR, " 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) { av_log(s->avctx, AV_LOG_ERROR, " 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)) { av_log(s->avctx, AV_LOG_ERROR, " 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++; } } } /* one last sanity check on the way out */ if (stream_ptr < s->size) av_log(s->avctx, AV_LOG_ERROR, " 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] = 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; /* no supplementary picture */ if (buf_size == 0) return 0; s->buf = buf; s->size = buf_size; 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; } switch (avctx->bits_per_sample) { case 8: msrle_decode_pal8(s); break; case 4: msrle_decode_pal4(s); break; default: av_log(avctx, AV_LOG_ERROR, "Don't know how to decode depth %u.\n", avctx->bits_per_sample); } *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->frame.data[0]) avctx->release_buffer(avctx, &s->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, };