2 * Kega Game Video (KGV1) decoder
3 * Copyright (c) 2010 Daniel Verkamp
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * Kega Game Video decoder
27 #include "libavutil/common.h"
28 #include "libavutil/intreadwrite.h"
29 #include "libavutil/imgutils.h"
34 AVCodecContext *avctx;
35 uint16_t *frame_buffer;
36 uint16_t *last_frame_buffer;
39 static void decode_flush(AVCodecContext *avctx)
41 KgvContext * const c = avctx->priv_data;
43 av_freep(&c->frame_buffer);
44 av_freep(&c->last_frame_buffer);
47 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
50 AVFrame *frame = data;
51 const uint8_t *buf = avpkt->data;
52 const uint8_t *buf_end = buf + avpkt->size;
53 KgvContext * const c = avctx->priv_data;
56 int outcnt = 0, maxcnt;
60 return AVERROR_INVALIDDATA;
66 if (w != avctx->width || h != avctx->height) {
67 av_freep(&c->frame_buffer);
68 av_freep(&c->last_frame_buffer);
69 if ((res = ff_set_dimensions(avctx, w, h)) < 0)
73 if (!c->frame_buffer) {
74 c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
75 c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
76 if (!c->frame_buffer || !c->last_frame_buffer) {
78 return AVERROR(ENOMEM);
84 if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
86 out = c->frame_buffer;
87 prev = c->last_frame_buffer;
89 for (i = 0; i < 8; i++)
92 while (outcnt < maxcnt && buf_end - 2 > buf) {
93 int code = AV_RL16(buf);
96 if (!(code & 0x8000)) {
97 out[outcnt++] = code; // rgb555 pixel coded directly
103 if ((code & 0x6000) == 0x6000) {
104 // copy from previous frame
105 int oidx = (code >> 10) & 7;
108 count = (code & 0x3FF) + 3;
110 if (offsets[oidx] < 0) {
111 if (buf_end - 3 < buf)
113 offsets[oidx] = AV_RL24(buf);
117 start = (outcnt + offsets[oidx]) % maxcnt;
119 if (maxcnt - start < count)
123 av_log(avctx, AV_LOG_ERROR,
124 "Frame reference does not exist\n");
131 // copy from earlier in this frame
132 int offset = (code & 0x1FFF) + 1;
134 if (!(code & 0x6000)) {
136 } else if ((code & 0x6000) == 0x2000) {
139 if (buf_end - 1 < buf)
148 inp_off = outcnt - offset;
151 if (maxcnt - outcnt < count)
154 for (i = inp_off; i < count + inp_off; i++) {
155 out[outcnt++] = inp[i];
161 av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
163 av_image_copy_plane(frame->data[0], frame->linesize[0],
164 (const uint8_t*)c->frame_buffer, avctx->width * 2,
165 avctx->width * 2, avctx->height);
166 FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer);
173 static av_cold int decode_init(AVCodecContext *avctx)
175 KgvContext * const c = avctx->priv_data;
178 avctx->pix_fmt = AV_PIX_FMT_RGB555;
183 static av_cold int decode_end(AVCodecContext *avctx)
189 AVCodec ff_kgv1_decoder = {
191 .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"),
192 .type = AVMEDIA_TYPE_VIDEO,
193 .id = AV_CODEC_ID_KGV1,
194 .priv_data_size = sizeof(KgvContext),
197 .decode = decode_frame,
198 .flush = decode_flush,
199 .capabilities = CODEC_CAP_DR1,