From 44aa9771c98be64e33af605797c08e86ccfdfef0 Mon Sep 17 00:00:00 2001 From: Kostya Shishkov Date: Thu, 18 Sep 2008 05:20:54 +0000 Subject: Factorize out code used for MS RLE format decoding in different decoders. Originally committed as revision 15356 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/msrledec.c | 254 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 254 insertions(+) create mode 100644 libavcodec/msrledec.c (limited to 'libavcodec/msrledec.c') diff --git a/libavcodec/msrledec.c b/libavcodec/msrledec.c new file mode 100644 index 0000000000..f44b8b6d12 --- /dev/null +++ b/libavcodec/msrledec.c @@ -0,0 +1,254 @@ +/* + * Micrsoft RLE Decoder + * Copyright (C) 2008 Konstantin Shishkov + * + * 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 msrledec.c + * MS RLE Decoder based on decoder by Mike Melanson and my own for TSCC + * For more information about the MS RLE format, visit: + * http://www.multimedia.cx/msrle.txt + */ + +#include "avcodec.h" + +#define FETCH_NEXT_STREAM_BYTE() \ + if (stream_ptr >= data_size) \ + { \ + av_log(avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \ + return -1; \ + } \ + stream_byte = data[stream_ptr++]; + +static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic, + const uint8_t *data, int data_size) +{ + 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 = pic->linesize[0]; + int row_ptr = (avctx->height - 1) * row_dec; + int frame_size = row_dec * avctx->height; + int i; + + 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 0; + } 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(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n"); + return -1; + } + + for (i = 0; i < rle_code; i++) { + if (pixel_ptr >= avctx->width) + break; + FETCH_NEXT_STREAM_BYTE(); + pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4; + pixel_ptr++; + if (i + 1 == rle_code && odd_pixel) + break; + if (pixel_ptr >= avctx->width) + break; + pic->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(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n"); + return -1; + } + FETCH_NEXT_STREAM_BYTE(); + for (i = 0; i < rle_code; i++) { + if (pixel_ptr >= avctx->width) + break; + if ((i & 1) == 0) + pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4; + else + pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F; + pixel_ptr++; + } + } + } + + /* one last sanity check on the way out */ + if (stream_ptr < data_size) { + av_log(avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n", + stream_ptr, data_size); + return -1; + } + + return 0; +} + + +static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic, int depth, + const uint8_t *data, int srcsize) +{ + uint8_t *output, *output_end; + const uint8_t* src = data; + int p1, p2, line=avctx->height, pos=0, i; + uint16_t pix16; + uint32_t pix32; + + output = pic->data[0] + (avctx->height - 1) * pic->linesize[0]; + output_end = pic->data[0] + (avctx->height) * pic->linesize[0]; + while(src < data + srcsize) { + p1 = *src++; + if(p1 == 0) { //Escape code + p2 = *src++; + if(p2 == 0) { //End-of-line + output = pic->data[0] + (--line) * pic->linesize[0]; + if (line < 0) + return -1; + pos = 0; + continue; + } else if(p2 == 1) { //End-of-picture + return 0; + } else if(p2 == 2) { //Skip + p1 = *src++; + p2 = *src++; + line -= p2; + if (line < 0) + return -1; + pos += p1; + output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3); + continue; + } + // Copy data + if (output + p2 * (depth >> 3) > output_end) { + src += p2 * (depth >> 3); + continue; + } + if ((depth == 8) || (depth == 24)) { + for(i = 0; i < p2 * (depth >> 3); i++) { + *output++ = *src++; + } + // RLE8 copy is actually padded - and runs are not! + if(depth == 8 && (p2 & 1)) { + src++; + } + } else if (depth == 16) { + for(i = 0; i < p2; i++) { + pix16 = AV_RL16(src); + src += 2; + *(uint16_t*)output = pix16; + output += 2; + } + } else if (depth == 32) { + for(i = 0; i < p2; i++) { + pix32 = AV_RL32(src); + src += 4; + *(uint32_t*)output = pix32; + output += 4; + } + } + pos += p2; + } else { //Run of pixels + int pix[4]; //original pixel + switch(depth){ + case 8: pix[0] = *src++; + break; + case 16: pix16 = AV_RL16(src); + src += 2; + *(uint16_t*)pix = pix16; + break; + case 24: pix[0] = *src++; + pix[1] = *src++; + pix[2] = *src++; + break; + case 32: pix32 = AV_RL32(src); + src += 4; + *(uint32_t*)pix = pix32; + break; + } + if (output + p1 * (depth >> 3) > output_end) + continue; + for(i = 0; i < p1; i++) { + switch(depth){ + case 8: *output++ = pix[0]; + break; + case 16: *(uint16_t*)output = pix16; + output += 2; + break; + case 24: *output++ = pix[0]; + *output++ = pix[1]; + *output++ = pix[2]; + break; + case 32: *(uint32_t*)output = pix32; + output += 4; + break; + } + } + pos += p1; + } + } + + av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no End-of-picture code\n"); + return 0; +} + + +int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic, int depth, + const uint8_t* data, int data_size) +{ + switch(depth){ + case 4: + return msrle_decode_pal4(avctx, pic, data, data_size); + case 8: + case 16: + case 24: + case 32: + return msrle_decode_8_16_24_32(avctx, pic, depth, data, data_size); + default: + av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth); + return -1; + } +} + -- cgit v1.2.3