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Diffstat (limited to 'ffmpeg/libavcodec/rl2.c')
| -rw-r--r-- | ffmpeg/libavcodec/rl2.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/rl2.c b/ffmpeg/libavcodec/rl2.c new file mode 100644 index 0000000..c8853de --- /dev/null +++ b/ffmpeg/libavcodec/rl2.c @@ -0,0 +1,226 @@ +/* + * 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 + */ + +/** + * @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 output 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] = 0xFFU << 24 | 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) + 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", + .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, + .long_name = NULL_IF_CONFIG_SMALL("RL2 video"), +}; |