yading@10: /* yading@10: * Kega Game Video (KGV1) decoder yading@10: * Copyright (c) 2010 Daniel Verkamp yading@10: * yading@10: * This file is part of FFmpeg. yading@10: * yading@10: * FFmpeg is free software; you can redistribute it and/or yading@10: * modify it under the terms of the GNU Lesser General Public yading@10: * License as published by the Free Software Foundation; either yading@10: * version 2.1 of the License, or (at your option) any later version. yading@10: * yading@10: * FFmpeg is distributed in the hope that it will be useful, yading@10: * but WITHOUT ANY WARRANTY; without even the implied warranty of yading@10: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yading@10: * Lesser General Public License for more details. yading@10: * yading@10: * You should have received a copy of the GNU Lesser General Public yading@10: * License along with FFmpeg; if not, write to the Free Software yading@10: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA yading@10: */ yading@10: yading@10: /** yading@10: * @file yading@10: * Kega Game Video decoder yading@10: */ yading@10: yading@10: #include "libavutil/common.h" yading@10: #include "libavutil/intreadwrite.h" yading@10: #include "libavutil/imgutils.h" yading@10: #include "avcodec.h" yading@10: #include "internal.h" yading@10: yading@10: typedef struct { yading@10: AVCodecContext *avctx; yading@10: AVFrame prev; yading@10: } KgvContext; yading@10: yading@10: static void decode_flush(AVCodecContext *avctx) yading@10: { yading@10: KgvContext * const c = avctx->priv_data; yading@10: yading@10: av_frame_unref(&c->prev); yading@10: } yading@10: yading@10: static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, yading@10: AVPacket *avpkt) yading@10: { yading@10: AVFrame *frame = data; yading@10: const uint8_t *buf = avpkt->data; yading@10: const uint8_t *buf_end = buf + avpkt->size; yading@10: KgvContext * const c = avctx->priv_data; yading@10: int offsets[8]; yading@10: uint8_t *out, *prev; yading@10: int outcnt = 0, maxcnt; yading@10: int w, h, i, res; yading@10: yading@10: if (avpkt->size < 2) yading@10: return AVERROR_INVALIDDATA; yading@10: yading@10: w = (buf[0] + 1) * 8; yading@10: h = (buf[1] + 1) * 8; yading@10: buf += 2; yading@10: yading@10: if ((res = av_image_check_size(w, h, 0, avctx)) < 0) yading@10: return res; yading@10: yading@10: if (w != avctx->width || h != avctx->height) { yading@10: av_frame_unref(&c->prev); yading@10: avcodec_set_dimensions(avctx, w, h); yading@10: } yading@10: yading@10: maxcnt = w * h; yading@10: yading@10: if ((res = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) yading@10: return res; yading@10: out = frame->data[0]; yading@10: if (c->prev.data[0]) { yading@10: prev = c->prev.data[0]; yading@10: } else { yading@10: prev = NULL; yading@10: } yading@10: yading@10: for (i = 0; i < 8; i++) yading@10: offsets[i] = -1; yading@10: yading@10: while (outcnt < maxcnt && buf_end - 2 >= buf) { yading@10: int code = AV_RL16(buf); yading@10: buf += 2; yading@10: yading@10: if (!(code & 0x8000)) { yading@10: AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly yading@10: outcnt++; yading@10: } else { yading@10: int count; yading@10: yading@10: if ((code & 0x6000) == 0x6000) { yading@10: // copy from previous frame yading@10: int oidx = (code >> 10) & 7; yading@10: int start; yading@10: yading@10: count = (code & 0x3FF) + 3; yading@10: yading@10: if (offsets[oidx] < 0) { yading@10: if (buf_end - 3 < buf) yading@10: break; yading@10: offsets[oidx] = AV_RL24(buf); yading@10: buf += 3; yading@10: } yading@10: yading@10: start = (outcnt + offsets[oidx]) % maxcnt; yading@10: yading@10: if (maxcnt - start < count || maxcnt - outcnt < count) yading@10: break; yading@10: yading@10: if (!prev) { yading@10: av_log(avctx, AV_LOG_ERROR, yading@10: "Frame reference does not exist\n"); yading@10: break; yading@10: } yading@10: yading@10: memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count); yading@10: } else { yading@10: // copy from earlier in this frame yading@10: int offset = (code & 0x1FFF) + 1; yading@10: yading@10: if (!(code & 0x6000)) { yading@10: count = 2; yading@10: } else if ((code & 0x6000) == 0x2000) { yading@10: count = 3; yading@10: } else { yading@10: if (buf_end - 1 < buf) yading@10: break; yading@10: count = 4 + *buf++; yading@10: } yading@10: yading@10: if (outcnt < offset || maxcnt - outcnt < count) yading@10: break; yading@10: yading@10: av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count); yading@10: } yading@10: outcnt += count; yading@10: } yading@10: } yading@10: yading@10: if (outcnt - maxcnt) yading@10: av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt); yading@10: yading@10: av_frame_unref(&c->prev); yading@10: if ((res = av_frame_ref(&c->prev, frame)) < 0) yading@10: return res; yading@10: yading@10: *got_frame = 1; yading@10: yading@10: return avpkt->size; yading@10: } yading@10: yading@10: static av_cold int decode_init(AVCodecContext *avctx) yading@10: { yading@10: KgvContext * const c = avctx->priv_data; yading@10: yading@10: c->avctx = avctx; yading@10: avctx->pix_fmt = AV_PIX_FMT_RGB555; yading@10: avctx->flags |= CODEC_FLAG_EMU_EDGE; yading@10: yading@10: return 0; yading@10: } yading@10: yading@10: static av_cold int decode_end(AVCodecContext *avctx) yading@10: { yading@10: decode_flush(avctx); yading@10: return 0; yading@10: } yading@10: yading@10: AVCodec ff_kgv1_decoder = { yading@10: .name = "kgv1", yading@10: .type = AVMEDIA_TYPE_VIDEO, yading@10: .id = AV_CODEC_ID_KGV1, yading@10: .priv_data_size = sizeof(KgvContext), yading@10: .init = decode_init, yading@10: .close = decode_end, yading@10: .decode = decode_frame, yading@10: .flush = decode_flush, yading@10: .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"), yading@10: .capabilities = CODEC_CAP_DR1, yading@10: };