mirror of
https://github.com/xenia-project/FFmpeg.git
synced 2024-12-13 14:25:52 +00:00
5918c5a4cc
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
188 lines
5.3 KiB
C
188 lines
5.3 KiB
C
/*
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* Kega Game Video (KGV1) decoder
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* Copyright (c) 2010 Daniel Verkamp
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Kega Game Video decoder
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*/
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#include "libavutil/common.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/imgutils.h"
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#include "avcodec.h"
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#include "internal.h"
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typedef struct {
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uint16_t *frame_buffer;
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uint16_t *last_frame_buffer;
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} KgvContext;
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static void decode_flush(AVCodecContext *avctx)
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{
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KgvContext * const c = avctx->priv_data;
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av_freep(&c->frame_buffer);
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av_freep(&c->last_frame_buffer);
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}
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static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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AVPacket *avpkt)
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{
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AVFrame *frame = data;
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const uint8_t *buf = avpkt->data;
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const uint8_t *buf_end = buf + avpkt->size;
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KgvContext * const c = avctx->priv_data;
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int offsets[8];
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uint8_t *out, *prev;
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int outcnt = 0, maxcnt;
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int w, h, i, res;
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if (avpkt->size < 2)
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return AVERROR_INVALIDDATA;
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w = (buf[0] + 1) * 8;
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h = (buf[1] + 1) * 8;
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buf += 2;
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if (w != avctx->width || h != avctx->height) {
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av_freep(&c->frame_buffer);
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av_freep(&c->last_frame_buffer);
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if ((res = ff_set_dimensions(avctx, w, h)) < 0)
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return res;
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}
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if (!c->frame_buffer) {
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c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
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c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
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if (!c->frame_buffer || !c->last_frame_buffer) {
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decode_flush(avctx);
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return AVERROR(ENOMEM);
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}
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}
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maxcnt = w * h;
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if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
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return res;
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out = (uint8_t*)c->frame_buffer;
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prev = (uint8_t*)c->last_frame_buffer;
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for (i = 0; i < 8; i++)
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offsets[i] = -1;
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while (outcnt < maxcnt && buf_end - 2 >= buf) {
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int code = AV_RL16(buf);
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buf += 2;
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if (!(code & 0x8000)) {
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AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
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outcnt++;
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} else {
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int count;
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if ((code & 0x6000) == 0x6000) {
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// copy from previous frame
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int oidx = (code >> 10) & 7;
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int start;
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count = (code & 0x3FF) + 3;
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if (offsets[oidx] < 0) {
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if (buf_end - 3 < buf)
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break;
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offsets[oidx] = AV_RL24(buf);
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buf += 3;
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}
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start = (outcnt + offsets[oidx]) % maxcnt;
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if (maxcnt - start < count || maxcnt - outcnt < count)
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break;
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if (!prev) {
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av_log(avctx, AV_LOG_ERROR,
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"Frame reference does not exist\n");
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break;
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}
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memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
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} else {
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// copy from earlier in this frame
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int offset = (code & 0x1FFF) + 1;
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if (!(code & 0x6000)) {
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count = 2;
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} else if ((code & 0x6000) == 0x2000) {
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count = 3;
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} else {
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if (buf_end - 1 < buf)
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break;
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count = 4 + *buf++;
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}
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if (outcnt < offset || maxcnt - outcnt < count)
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break;
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av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
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}
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outcnt += count;
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}
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}
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if (outcnt - maxcnt)
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av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
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av_image_copy_plane(frame->data[0], frame->linesize[0],
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(const uint8_t*)c->frame_buffer, avctx->width * 2,
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avctx->width * 2, avctx->height);
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FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer);
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*got_frame = 1;
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return avpkt->size;
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}
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static av_cold int decode_init(AVCodecContext *avctx)
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{
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avctx->pix_fmt = AV_PIX_FMT_RGB555;
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return 0;
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}
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static av_cold int decode_end(AVCodecContext *avctx)
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{
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decode_flush(avctx);
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return 0;
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}
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AVCodec ff_kgv1_decoder = {
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.name = "kgv1",
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.long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_KGV1,
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.priv_data_size = sizeof(KgvContext),
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.init = decode_init,
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.close = decode_end,
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.decode = decode_frame,
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.flush = decode_flush,
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.capabilities = CODEC_CAP_DR1,
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};
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