2 * Kega Game Video (KGV1) decoder
3 * Copyright (c) 2010 Daniel Verkamp
5 * This file is part of FFmpeg.
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.
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.
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
24 * Kega Game Video decoder
27 #include "libavutil/common.h"
28 #include "libavutil/intreadwrite.h"
29 #include "libavutil/imgutils.h"
33 typedef struct KgvContext {
34 uint16_t *frame_buffer;
35 uint16_t *last_frame_buffer;
38 static void decode_flush(AVCodecContext *avctx)
40 KgvContext * const c = avctx->priv_data;
42 av_freep(&c->frame_buffer);
43 av_freep(&c->last_frame_buffer);
46 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
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;
55 int outcnt = 0, maxcnt;
59 return AVERROR_INVALIDDATA;
65 if (avpkt->size < 2 + w*h / 513)
66 return AVERROR_INVALIDDATA;
68 if (w != avctx->width || h != avctx->height) {
69 av_freep(&c->frame_buffer);
70 av_freep(&c->last_frame_buffer);
71 if ((res = ff_set_dimensions(avctx, w, h)) < 0)
75 if (!c->frame_buffer) {
76 c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
77 c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
78 if (!c->frame_buffer || !c->last_frame_buffer) {
80 return AVERROR(ENOMEM);
86 if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
88 out = (uint8_t*)c->frame_buffer;
89 prev = (uint8_t*)c->last_frame_buffer;
91 for (i = 0; i < 8; i++)
94 while (outcnt < maxcnt && buf_end - 2 >= buf) {
95 int code = AV_RL16(buf);
98 if (!(code & 0x8000)) {
99 AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
104 if ((code & 0x6000) == 0x6000) {
105 // copy from previous frame
106 int oidx = (code >> 10) & 7;
109 count = (code & 0x3FF) + 3;
111 if (offsets[oidx] < 0) {
112 if (buf_end - 3 < buf)
114 offsets[oidx] = AV_RL24(buf);
118 start = (outcnt + offsets[oidx]) % maxcnt;
120 if (maxcnt - start < count || maxcnt - outcnt < count)
124 av_log(avctx, AV_LOG_ERROR,
125 "Frame reference does not exist\n");
129 memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
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)
144 if (outcnt < offset || maxcnt - outcnt < count)
147 av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
154 av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
156 av_image_copy_plane(frame->data[0], frame->linesize[0],
157 (const uint8_t*)c->frame_buffer, avctx->width * 2,
158 avctx->width * 2, avctx->height);
159 FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer);
166 static av_cold int decode_init(AVCodecContext *avctx)
168 avctx->pix_fmt = AV_PIX_FMT_RGB555;
173 static av_cold int decode_end(AVCodecContext *avctx)
179 AVCodec ff_kgv1_decoder = {
181 .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"),
182 .type = AVMEDIA_TYPE_VIDEO,
183 .id = AV_CODEC_ID_KGV1,
184 .priv_data_size = sizeof(KgvContext),
187 .decode = decode_frame,
188 .flush = decode_flush,
189 .capabilities = AV_CODEC_CAP_DR1,