/* * RL2 Video Decoder * Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de) * * 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 */ /** * RL2 Video Decoder * @file rl2.c * @author Sascha Sommer (saschasommer@freenet.de) * For more information about the RL2 format, visit: * http://wiki.multimedia.cx/index.php?title=RL2 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "avcodec.h" #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette typedef struct Rl2Context { AVCodecContext *avctx; AVFrame frame; unsigned short video_base; ///< initial drawing offset unsigned int clr_count; ///< number of used colors (currently unused) unsigned char* back_frame; ///< background frame unsigned int palette[AVPALETTE_COUNT]; } Rl2Context; /** * Run Length Decode a single 320x200 frame * @param s rl2 context * @param buf input buffer * @param size input buffer size * @param out ouput buffer * @param stride stride of the output buffer * @param video_base offset of the rle data inside the frame */ static void rl2_rle_decode(Rl2Context *s,const unsigned char* in,int size, unsigned char* out,int stride,int video_base){ int base_x = video_base % s->avctx->width; int base_y = video_base / s->avctx->width; int stride_adj = stride - s->avctx->width; int i; const unsigned char* back_frame = s->back_frame; const unsigned char* in_end = in + size; const unsigned char* out_end = out + stride * s->avctx->height; unsigned char* line_end = out + s->avctx->width; /** copy start of the background frame */ for(i=0;i<=base_y;i++){ if(s->back_frame) memcpy(out,back_frame,s->avctx->width); out += stride; back_frame += s->avctx->width; } back_frame += base_x - s->avctx->width; line_end = out - stride_adj; out += base_x - stride; /** decode the variable part of the frame */ while(in < in_end){ unsigned char val = *in++; int len = 1; if(val >= 0x80){ if(in >= in_end) break; len = *in++; if(!len) break; } if(len >= out_end - out) break; if(s->back_frame) val |= 0x80; else val &= ~0x80; while(len--){ *out++ = (val == 0x80)? *back_frame:val; back_frame++; if(out == line_end){ out += stride_adj; line_end += stride; if(len >= out_end - out) break; } } } /** copy the rest from the background frame */ if(s->back_frame){ while(out < out_end){ memcpy(out, back_frame, line_end - out); back_frame += line_end - out; out = line_end + stride_adj; line_end += stride; } } } /** * Initialize the decoder * @param avctx decoder context * @return 0 success, -1 on error */ static av_cold int rl2_decode_init(AVCodecContext *avctx) { Rl2Context *s = avctx->priv_data; int back_size; int i; s->avctx = avctx; avctx->pix_fmt = PIX_FMT_PAL8; /** parse extra data */ if(!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE){ av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n"); return -1; } /** get frame_offset */ s->video_base = AV_RL16(&avctx->extradata[0]); s->clr_count = AV_RL32(&avctx->extradata[2]); if(s->video_base >= avctx->width * avctx->height){ av_log(avctx, AV_LOG_ERROR, "invalid video_base\n"); return -1; } /** initialize palette */ for(i=0;i<AVPALETTE_COUNT;i++) s->palette[i] = AV_RB24(&avctx->extradata[6 + i * 3]); /** decode background frame if present */ back_size = avctx->extradata_size - EXTRADATA1_SIZE; if(back_size > 0){ unsigned char* back_frame = av_mallocz(avctx->width*avctx->height); if(!back_frame) return -1; rl2_rle_decode(s,avctx->extradata + EXTRADATA1_SIZE,back_size, back_frame,avctx->width,0); s->back_frame = back_frame; } return 0; } /** * Decode a single frame * @param avctx decoder context * @param data decoded frame * @param data_size size of the decoded frame * @param buf input buffer * @param buf_size input buffer size * @return 0 success, -1 on error */ static int rl2_decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size) { Rl2Context *s = avctx->priv_data; if(s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); /** get buffer */ s->frame.reference= 0; if(avctx->get_buffer(avctx, &s->frame)) { av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return -1; } /** run length decode */ rl2_rle_decode(s,buf,buf_size,s->frame.data[0],s->frame.linesize[0],s->video_base); /** make the palette available on the way out */ memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE); *data_size = sizeof(AVFrame); *(AVFrame*)data = s->frame; /** report that the buffer was completely consumed */ return buf_size; } /** * Uninit decoder * @param avctx decoder context * @return 0 success, -1 on error */ static av_cold int rl2_decode_end(AVCodecContext *avctx) { Rl2Context *s = avctx->priv_data; if(s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); av_free(s->back_frame); return 0; } AVCodec rl2_decoder = { "rl2", CODEC_TYPE_VIDEO, CODEC_ID_RL2, sizeof(Rl2Context), rl2_decode_init, NULL, rl2_decode_end, rl2_decode_frame, CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("RL2 video"), };