diff options
Diffstat (limited to 'ffmpeg1/libavcodec/kgv1dec.c')
| -rw-r--r-- | ffmpeg1/libavcodec/kgv1dec.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/kgv1dec.c b/ffmpeg1/libavcodec/kgv1dec.c new file mode 100644 index 0000000..9c48239 --- /dev/null +++ b/ffmpeg1/libavcodec/kgv1dec.c @@ -0,0 +1,185 @@ +/* + * Kega Game Video (KGV1) decoder + * Copyright (c) 2010 Daniel Verkamp + * + * 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 + * Kega Game Video decoder + */ + +#include "libavutil/common.h" +#include "libavutil/intreadwrite.h" +#include "libavutil/imgutils.h" +#include "avcodec.h" +#include "internal.h" + +typedef struct { + AVCodecContext *avctx; + AVFrame prev; +} KgvContext; + +static void decode_flush(AVCodecContext *avctx) +{ + KgvContext * const c = avctx->priv_data; + + av_frame_unref(&c->prev); +} + +static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, + AVPacket *avpkt) +{ + AVFrame *frame = data; + const uint8_t *buf = avpkt->data; + const uint8_t *buf_end = buf + avpkt->size; + KgvContext * const c = avctx->priv_data; + int offsets[8]; + uint8_t *out, *prev; + int outcnt = 0, maxcnt; + int w, h, i, res; + + if (avpkt->size < 2) + return AVERROR_INVALIDDATA; + + w = (buf[0] + 1) * 8; + h = (buf[1] + 1) * 8; + buf += 2; + + if ((res = av_image_check_size(w, h, 0, avctx)) < 0) + return res; + + if (w != avctx->width || h != avctx->height) { + av_frame_unref(&c->prev); + avcodec_set_dimensions(avctx, w, h); + } + + maxcnt = w * h; + + if ((res = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) + return res; + out = frame->data[0]; + if (c->prev.data[0]) { + prev = c->prev.data[0]; + } else { + prev = NULL; + } + + for (i = 0; i < 8; i++) + offsets[i] = -1; + + while (outcnt < maxcnt && buf_end - 2 >= buf) { + int code = AV_RL16(buf); + buf += 2; + + if (!(code & 0x8000)) { + AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly + outcnt++; + } else { + int count; + + if ((code & 0x6000) == 0x6000) { + // copy from previous frame + int oidx = (code >> 10) & 7; + int start; + + count = (code & 0x3FF) + 3; + + if (offsets[oidx] < 0) { + if (buf_end - 3 < buf) + break; + offsets[oidx] = AV_RL24(buf); + buf += 3; + } + + start = (outcnt + offsets[oidx]) % maxcnt; + + if (maxcnt - start < count || maxcnt - outcnt < count) + break; + + if (!prev) { + av_log(avctx, AV_LOG_ERROR, + "Frame reference does not exist\n"); + break; + } + + memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count); + } else { + // copy from earlier in this frame + int offset = (code & 0x1FFF) + 1; + + if (!(code & 0x6000)) { + count = 2; + } else if ((code & 0x6000) == 0x2000) { + count = 3; + } else { + if (buf_end - 1 < buf) + break; + count = 4 + *buf++; + } + + if (outcnt < offset || maxcnt - outcnt < count) + break; + + av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count); + } + outcnt += count; + } + } + + if (outcnt - maxcnt) + av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt); + + av_frame_unref(&c->prev); + if ((res = av_frame_ref(&c->prev, frame)) < 0) + return res; + + *got_frame = 1; + + return avpkt->size; +} + +static av_cold int decode_init(AVCodecContext *avctx) +{ + KgvContext * const c = avctx->priv_data; + + c->avctx = avctx; + avctx->pix_fmt = AV_PIX_FMT_RGB555; + avctx->flags |= CODEC_FLAG_EMU_EDGE; + + return 0; +} + +static av_cold int decode_end(AVCodecContext *avctx) +{ + decode_flush(avctx); + return 0; +} + +AVCodec ff_kgv1_decoder = { + .name = "kgv1", + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_KGV1, + .priv_data_size = sizeof(KgvContext), + .init = decode_init, + .close = decode_end, + .decode = decode_frame, + .flush = decode_flush, + .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"), + .capabilities = CODEC_CAP_DR1, +}; |