FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/kgv1dec.c
Date: 2025-10-24 21:16:34
Exec Total Coverage
Lines: 66 80 82.5%
Functions: 4 4 100.0%
Branches: 32 50 64.0%
Line Branch Exec Source
1 /*
2 * Kega Game Video (KGV1) decoder
3 * Copyright (c) 2010 Daniel Verkamp
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /**
23 * @file
24 * Kega Game Video decoder
25 */
26
27 #include "libavutil/common.h"
28 #include "libavutil/intreadwrite.h"
29 #include "libavutil/imgutils.h"
30 #include "libavutil/mem.h"
31 #include "avcodec.h"
32 #include "codec_internal.h"
33 #include "decode.h"
34
35 typedef struct KgvContext {
36 uint16_t *frame_buffer;
37 uint16_t *last_frame_buffer;
38 } KgvContext;
39
40 2 static void decode_flush(AVCodecContext *avctx)
41 {
42 2 KgvContext * const c = avctx->priv_data;
43
44 2 av_freep(&c->frame_buffer);
45 2 av_freep(&c->last_frame_buffer);
46 2 }
47
48 313 static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
49 int *got_frame, AVPacket *avpkt)
50 {
51 313 const uint8_t *buf = avpkt->data;
52 313 const uint8_t *buf_end = buf + avpkt->size;
53 313 KgvContext * const c = avctx->priv_data;
54 int offsets[8];
55 uint8_t *out, *prev;
56 313 int outcnt = 0, maxcnt;
57 int w, h, i, res;
58
59
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 313 if (avpkt->size < 2)
60 ✗ return AVERROR_INVALIDDATA;
61
62 313 w = (buf[0] + 1) * 8;
63 313 h = (buf[1] + 1) * 8;
64 313 buf += 2;
65
66
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 313 if (avpkt->size < 2 + w*h / 513)
67 ✗ return AVERROR_INVALIDDATA;
68
69
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 313 if (w != avctx->width || h != avctx->height) {
70 ✗ av_freep(&c->frame_buffer);
71 ✗ av_freep(&c->last_frame_buffer);
72 ✗ if ((res = ff_set_dimensions(avctx, w, h)) < 0)
73 ✗ return res;
74 }
75
76
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 313 if (!c->frame_buffer) {
77 1 c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
78 1 c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2);
79
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 1 if (!c->frame_buffer || !c->last_frame_buffer) {
80 ✗ decode_flush(avctx);
81 ✗ return AVERROR(ENOMEM);
82 }
83 }
84
85 313 maxcnt = w * h;
86
87
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 313 if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
88 ✗ return res;
89 313 out = (uint8_t*)c->frame_buffer;
90 313 prev = (uint8_t*)c->last_frame_buffer;
91
92
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 2817 for (i = 0; i < 8; i++)
93 2504 offsets[i] = -1;
94
95
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 51104 while (outcnt < maxcnt && buf_end - 2 >= buf) {
96 50791 int code = AV_RL16(buf);
97 50791 buf += 2;
98
99
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 50791 if (!(code & 0x8000)) {
100 756 AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
101 756 outcnt++;
102 } else {
103 int count;
104
105
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 50035 if ((code & 0x6000) == 0x6000) {
106 // copy from previous frame
107 22112 int oidx = (code >> 10) & 7;
108 int start;
109
110 22112 count = (code & 0x3FF) + 3;
111
112
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 22112 if (offsets[oidx] < 0) {
113
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 304 if (buf_end - 3 < buf)
114 ✗ break;
115 304 offsets[oidx] = AV_RL24(buf);
116 304 buf += 3;
117 }
118
119 22112 start = (outcnt + offsets[oidx]) % maxcnt;
120
121
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 22112 if (maxcnt - start < count || maxcnt - outcnt < count)
122 break;
123
124
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 22112 if (!prev) {
125 ✗ av_log(avctx, AV_LOG_ERROR,
126 "Frame reference does not exist\n");
127 ✗ break;
128 }
129
130 22112 memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
131 } else {
132 // copy from earlier in this frame
133 27923 int offset = (code & 0x1FFF) + 1;
134
135
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 27923 if (!(code & 0x6000)) {
136 1091 count = 2;
137
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 26832 } else if ((code & 0x6000) == 0x2000) {
138 776 count = 3;
139 } else {
140
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 26056 if (buf_end - 1 < buf)
141 ✗ break;
142 26056 count = 4 + *buf++;
143 }
144
145
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 27923 if (outcnt < offset || maxcnt - outcnt < count)
146 break;
147
148 27923 av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
149 }
150 50035 outcnt += count;
151 }
152 }
153
154
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 313 if (outcnt - maxcnt)
155 ✗ av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
156
157 313 av_image_copy_plane(frame->data[0], frame->linesize[0],
158 313 (const uint8_t*)c->frame_buffer, avctx->width * 2,
159 313 avctx->width * 2, avctx->height);
160 313 FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer);
161
162 313 *got_frame = 1;
163
164 313 return avpkt->size;
165 }
166
167 2 static av_cold int decode_init(AVCodecContext *avctx)
168 {
169 2 avctx->pix_fmt = AV_PIX_FMT_RGB555;
170
171 2 return 0;
172 }
173
174 2 static av_cold int decode_end(AVCodecContext *avctx)
175 {
176 2 decode_flush(avctx);
177 2 return 0;
178 }
179
180 const FFCodec ff_kgv1_decoder = {
181 .p.name = "kgv1",
182 CODEC_LONG_NAME("Kega Game Video"),
183 .p.type = AVMEDIA_TYPE_VIDEO,
184 .p.id = AV_CODEC_ID_KGV1,
185 .priv_data_size = sizeof(KgvContext),
186 .init = decode_init,
187 .close = decode_end,
188 FF_CODEC_DECODE_CB(decode_frame),
189 .flush = decode_flush,
190 .p.capabilities = AV_CODEC_CAP_DR1,
191 };
192