| 1 | /* |
| 2 | * RL2 Video Decoder |
| 3 | * Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de) |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | /** |
| 23 | * @file |
| 24 | * RL2 Video Decoder |
| 25 | * @author Sascha Sommer (saschasommer@freenet.de) |
| 26 | * @see http://wiki.multimedia.cx/index.php?title=RL2 |
| 27 | */ |
| 28 | |
| 29 | #include <stdio.h> |
| 30 | #include <stdlib.h> |
| 31 | #include <string.h> |
| 32 | |
| 33 | #include "libavutil/internal.h" |
| 34 | #include "libavutil/intreadwrite.h" |
| 35 | #include "libavutil/mem.h" |
| 36 | #include "avcodec.h" |
| 37 | #include "internal.h" |
| 38 | |
| 39 | |
| 40 | #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette |
| 41 | |
| 42 | typedef struct Rl2Context { |
| 43 | AVCodecContext *avctx; |
| 44 | |
| 45 | uint16_t video_base; ///< initial drawing offset |
| 46 | uint32_t clr_count; ///< number of used colors (currently unused) |
| 47 | uint8_t *back_frame; ///< background frame |
| 48 | uint32_t palette[AVPALETTE_COUNT]; |
| 49 | } Rl2Context; |
| 50 | |
| 51 | /** |
| 52 | * Run Length Decode a single 320x200 frame |
| 53 | * @param s rl2 context |
| 54 | * @param in input buffer |
| 55 | * @param size input buffer size |
| 56 | * @param out output buffer |
| 57 | * @param stride stride of the output buffer |
| 58 | * @param video_base offset of the rle data inside the frame |
| 59 | */ |
| 60 | static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, |
| 61 | uint8_t *out, int stride, int video_base) |
| 62 | { |
| 63 | int base_x = video_base % s->avctx->width; |
| 64 | int base_y = video_base / s->avctx->width; |
| 65 | int stride_adj = stride - s->avctx->width; |
| 66 | int i; |
| 67 | const uint8_t *back_frame = s->back_frame; |
| 68 | const uint8_t *in_end = in + size; |
| 69 | const uint8_t *out_end = out + stride * s->avctx->height; |
| 70 | uint8_t *line_end; |
| 71 | |
| 72 | /** copy start of the background frame */ |
| 73 | for (i = 0; i <= base_y; i++) { |
| 74 | if (s->back_frame) |
| 75 | memcpy(out, back_frame, s->avctx->width); |
| 76 | out += stride; |
| 77 | back_frame += s->avctx->width; |
| 78 | } |
| 79 | back_frame += base_x - s->avctx->width; |
| 80 | line_end = out - stride_adj; |
| 81 | out += base_x - stride; |
| 82 | |
| 83 | /** decode the variable part of the frame */ |
| 84 | while (in < in_end) { |
| 85 | uint8_t val = *in++; |
| 86 | int len = 1; |
| 87 | if (val >= 0x80) { |
| 88 | if (in >= in_end) |
| 89 | break; |
| 90 | len = *in++; |
| 91 | if (!len) |
| 92 | break; |
| 93 | } |
| 94 | |
| 95 | if (len >= out_end - out) |
| 96 | break; |
| 97 | |
| 98 | if (s->back_frame) |
| 99 | val |= 0x80; |
| 100 | else |
| 101 | val &= ~0x80; |
| 102 | |
| 103 | while (len--) { |
| 104 | *out++ = (val == 0x80) ? *back_frame : val; |
| 105 | back_frame++; |
| 106 | if (out == line_end) { |
| 107 | out += stride_adj; |
| 108 | line_end += stride; |
| 109 | if (len >= out_end - out) |
| 110 | break; |
| 111 | } |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | /** copy the rest from the background frame */ |
| 116 | if (s->back_frame) { |
| 117 | while (out < out_end) { |
| 118 | memcpy(out, back_frame, line_end - out); |
| 119 | back_frame += line_end - out; |
| 120 | out = line_end + stride_adj; |
| 121 | line_end += stride; |
| 122 | } |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | |
| 127 | /** |
| 128 | * Initialize the decoder |
| 129 | * @param avctx decoder context |
| 130 | * @return 0 success, -1 on error |
| 131 | */ |
| 132 | static av_cold int rl2_decode_init(AVCodecContext *avctx) |
| 133 | { |
| 134 | Rl2Context *s = avctx->priv_data; |
| 135 | int back_size; |
| 136 | int i; |
| 137 | |
| 138 | s->avctx = avctx; |
| 139 | avctx->pix_fmt = AV_PIX_FMT_PAL8; |
| 140 | |
| 141 | /** parse extra data */ |
| 142 | if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) { |
| 143 | av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n"); |
| 144 | return AVERROR(EINVAL); |
| 145 | } |
| 146 | |
| 147 | /** get frame_offset */ |
| 148 | s->video_base = AV_RL16(&avctx->extradata[0]); |
| 149 | s->clr_count = AV_RL32(&avctx->extradata[2]); |
| 150 | |
| 151 | if (s->video_base >= avctx->width * avctx->height) { |
| 152 | av_log(avctx, AV_LOG_ERROR, "invalid video_base\n"); |
| 153 | return AVERROR_INVALIDDATA; |
| 154 | } |
| 155 | |
| 156 | /** initialize palette */ |
| 157 | for (i = 0; i < AVPALETTE_COUNT; i++) |
| 158 | s->palette[i] = 0xFFU << 24 | AV_RB24(&avctx->extradata[6 + i * 3]); |
| 159 | |
| 160 | /** decode background frame if present */ |
| 161 | back_size = avctx->extradata_size - EXTRADATA1_SIZE; |
| 162 | |
| 163 | if (back_size > 0) { |
| 164 | uint8_t *back_frame = av_mallocz(avctx->width*avctx->height); |
| 165 | if (!back_frame) |
| 166 | return AVERROR(ENOMEM); |
| 167 | rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size, |
| 168 | back_frame, avctx->width, 0); |
| 169 | s->back_frame = back_frame; |
| 170 | } |
| 171 | return 0; |
| 172 | } |
| 173 | |
| 174 | |
| 175 | static int rl2_decode_frame(AVCodecContext *avctx, |
| 176 | void *data, int *got_frame, |
| 177 | AVPacket *avpkt) |
| 178 | { |
| 179 | AVFrame *frame = data; |
| 180 | const uint8_t *buf = avpkt->data; |
| 181 | int ret, buf_size = avpkt->size; |
| 182 | Rl2Context *s = avctx->priv_data; |
| 183 | |
| 184 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 185 | return ret; |
| 186 | |
| 187 | /** run length decode */ |
| 188 | rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0], |
| 189 | s->video_base); |
| 190 | |
| 191 | /** make the palette available on the way out */ |
| 192 | memcpy(frame->data[1], s->palette, AVPALETTE_SIZE); |
| 193 | |
| 194 | *got_frame = 1; |
| 195 | |
| 196 | /** report that the buffer was completely consumed */ |
| 197 | return buf_size; |
| 198 | } |
| 199 | |
| 200 | |
| 201 | /** |
| 202 | * Uninit decoder |
| 203 | * @param avctx decoder context |
| 204 | * @return 0 success, -1 on error |
| 205 | */ |
| 206 | static av_cold int rl2_decode_end(AVCodecContext *avctx) |
| 207 | { |
| 208 | Rl2Context *s = avctx->priv_data; |
| 209 | |
| 210 | av_free(s->back_frame); |
| 211 | |
| 212 | return 0; |
| 213 | } |
| 214 | |
| 215 | |
| 216 | AVCodec ff_rl2_decoder = { |
| 217 | .name = "rl2", |
| 218 | .long_name = NULL_IF_CONFIG_SMALL("RL2 video"), |
| 219 | .type = AVMEDIA_TYPE_VIDEO, |
| 220 | .id = AV_CODEC_ID_RL2, |
| 221 | .priv_data_size = sizeof(Rl2Context), |
| 222 | .init = rl2_decode_init, |
| 223 | .close = rl2_decode_end, |
| 224 | .decode = rl2_decode_frame, |
| 225 | .capabilities = CODEC_CAP_DR1, |
| 226 | }; |