| 1 | /* |
| 2 | * Kega Game Video (KGV1) decoder |
| 3 | * Copyright (c) 2010 Daniel Verkamp |
| 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 | * Kega Game Video decoder |
| 25 | */ |
| 26 | |
| 27 | #include "libavutil/common.h" |
| 28 | #include "libavutil/intreadwrite.h" |
| 29 | #include "libavutil/imgutils.h" |
| 30 | #include "avcodec.h" |
| 31 | #include "internal.h" |
| 32 | |
| 33 | typedef struct { |
| 34 | uint16_t *frame_buffer; |
| 35 | uint16_t *last_frame_buffer; |
| 36 | } KgvContext; |
| 37 | |
| 38 | static void decode_flush(AVCodecContext *avctx) |
| 39 | { |
| 40 | KgvContext * const c = avctx->priv_data; |
| 41 | |
| 42 | av_freep(&c->frame_buffer); |
| 43 | av_freep(&c->last_frame_buffer); |
| 44 | } |
| 45 | |
| 46 | static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, |
| 47 | AVPacket *avpkt) |
| 48 | { |
| 49 | AVFrame *frame = data; |
| 50 | const uint8_t *buf = avpkt->data; |
| 51 | const uint8_t *buf_end = buf + avpkt->size; |
| 52 | KgvContext * const c = avctx->priv_data; |
| 53 | int offsets[8]; |
| 54 | uint8_t *out, *prev; |
| 55 | int outcnt = 0, maxcnt; |
| 56 | int w, h, i, res; |
| 57 | |
| 58 | if (avpkt->size < 2) |
| 59 | return AVERROR_INVALIDDATA; |
| 60 | |
| 61 | w = (buf[0] + 1) * 8; |
| 62 | h = (buf[1] + 1) * 8; |
| 63 | buf += 2; |
| 64 | |
| 65 | if (w != avctx->width || h != avctx->height) { |
| 66 | av_freep(&c->frame_buffer); |
| 67 | av_freep(&c->last_frame_buffer); |
| 68 | if ((res = ff_set_dimensions(avctx, w, h)) < 0) |
| 69 | return res; |
| 70 | } |
| 71 | |
| 72 | if (!c->frame_buffer) { |
| 73 | c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2); |
| 74 | c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2); |
| 75 | if (!c->frame_buffer || !c->last_frame_buffer) { |
| 76 | decode_flush(avctx); |
| 77 | return AVERROR(ENOMEM); |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | maxcnt = w * h; |
| 82 | |
| 83 | if ((res = ff_get_buffer(avctx, frame, 0)) < 0) |
| 84 | return res; |
| 85 | out = (uint8_t*)c->frame_buffer; |
| 86 | prev = (uint8_t*)c->last_frame_buffer; |
| 87 | |
| 88 | for (i = 0; i < 8; i++) |
| 89 | offsets[i] = -1; |
| 90 | |
| 91 | while (outcnt < maxcnt && buf_end - 2 >= buf) { |
| 92 | int code = AV_RL16(buf); |
| 93 | buf += 2; |
| 94 | |
| 95 | if (!(code & 0x8000)) { |
| 96 | AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly |
| 97 | outcnt++; |
| 98 | } else { |
| 99 | int count; |
| 100 | |
| 101 | if ((code & 0x6000) == 0x6000) { |
| 102 | // copy from previous frame |
| 103 | int oidx = (code >> 10) & 7; |
| 104 | int start; |
| 105 | |
| 106 | count = (code & 0x3FF) + 3; |
| 107 | |
| 108 | if (offsets[oidx] < 0) { |
| 109 | if (buf_end - 3 < buf) |
| 110 | break; |
| 111 | offsets[oidx] = AV_RL24(buf); |
| 112 | buf += 3; |
| 113 | } |
| 114 | |
| 115 | start = (outcnt + offsets[oidx]) % maxcnt; |
| 116 | |
| 117 | if (maxcnt - start < count || maxcnt - outcnt < count) |
| 118 | break; |
| 119 | |
| 120 | if (!prev) { |
| 121 | av_log(avctx, AV_LOG_ERROR, |
| 122 | "Frame reference does not exist\n"); |
| 123 | break; |
| 124 | } |
| 125 | |
| 126 | memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count); |
| 127 | } else { |
| 128 | // copy from earlier in this frame |
| 129 | int offset = (code & 0x1FFF) + 1; |
| 130 | |
| 131 | if (!(code & 0x6000)) { |
| 132 | count = 2; |
| 133 | } else if ((code & 0x6000) == 0x2000) { |
| 134 | count = 3; |
| 135 | } else { |
| 136 | if (buf_end - 1 < buf) |
| 137 | break; |
| 138 | count = 4 + *buf++; |
| 139 | } |
| 140 | |
| 141 | if (outcnt < offset || maxcnt - outcnt < count) |
| 142 | break; |
| 143 | |
| 144 | av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count); |
| 145 | } |
| 146 | outcnt += count; |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | if (outcnt - maxcnt) |
| 151 | av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt); |
| 152 | |
| 153 | av_image_copy_plane(frame->data[0], frame->linesize[0], |
| 154 | (const uint8_t*)c->frame_buffer, avctx->width * 2, |
| 155 | avctx->width * 2, avctx->height); |
| 156 | FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer); |
| 157 | |
| 158 | *got_frame = 1; |
| 159 | |
| 160 | return avpkt->size; |
| 161 | } |
| 162 | |
| 163 | static av_cold int decode_init(AVCodecContext *avctx) |
| 164 | { |
| 165 | avctx->pix_fmt = AV_PIX_FMT_RGB555; |
| 166 | |
| 167 | return 0; |
| 168 | } |
| 169 | |
| 170 | static av_cold int decode_end(AVCodecContext *avctx) |
| 171 | { |
| 172 | decode_flush(avctx); |
| 173 | return 0; |
| 174 | } |
| 175 | |
| 176 | AVCodec ff_kgv1_decoder = { |
| 177 | .name = "kgv1", |
| 178 | .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"), |
| 179 | .type = AVMEDIA_TYPE_VIDEO, |
| 180 | .id = AV_CODEC_ID_KGV1, |
| 181 | .priv_data_size = sizeof(KgvContext), |
| 182 | .init = decode_init, |
| 183 | .close = decode_end, |
| 184 | .decode = decode_frame, |
| 185 | .flush = decode_flush, |
| 186 | .capabilities = CODEC_CAP_DR1, |
| 187 | }; |