/* * RL2 Video Decoder * Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de) * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * RL2 Video Decoder * @author Sascha Sommer (saschasommer@freenet.de) * @see http://wiki.multimedia.cx/index.php?title=RL2 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "libavutil/internal.h" #include "libavutil/intreadwrite.h" #include "libavutil/mem.h" #include "avcodec.h" #include "internal.h" #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette typedef struct Rl2Context { AVCodecContext *avctx; uint16_t video_base; ///< initial drawing offset uint32_t clr_count; ///< number of used colors (currently unused) uint8_t *back_frame; ///< background frame uint32_t palette[AVPALETTE_COUNT]; } Rl2Context; /** * Run Length Decode a single 320x200 frame * @param s rl2 context * @param in 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 uint8_t *in, int size, uint8_t *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 uint8_t *back_frame = s->back_frame; const uint8_t *in_end = in + size; const uint8_t *out_end = out + stride * s->avctx->height; uint8_t *line_end; /** 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) { uint8_t 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 = AV_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 AVERROR(EINVAL); } /** 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 AVERROR_INVALIDDATA; } /** 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) { uint8_t *back_frame = av_mallocz(avctx->width*avctx->height); if (!back_frame) return AVERROR(ENOMEM); rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size, back_frame, avctx->width, 0); s->back_frame = back_frame; } return 0; } static int rl2_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { AVFrame *frame = data; const uint8_t *buf = avpkt->data; int ret, buf_size = avpkt->size; Rl2Context *s = avctx->priv_data; if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) { av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } /** run length decode */ rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0], s->video_base); /** make the palette available on the way out */ memcpy(frame->data[1], s->palette, AVPALETTE_SIZE); *got_frame = 1; /** 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; av_free(s->back_frame); return 0; } AVCodec ff_rl2_decoder = { .name = "rl2", .long_name = NULL_IF_CONFIG_SMALL("RL2 video"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_RL2, .priv_data_size = sizeof(Rl2Context), .init = rl2_decode_init, .close = rl2_decode_end, .decode = rl2_decode_frame, .capabilities = CODEC_CAP_DR1, };