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kgv1dec.c
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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 "avcodec.h"
31 #include "internal.h"
32 
33 typedef struct KgvContext {
34  uint16_t *frame_buffer;
35  uint16_t *last_frame_buffer;
36 } KgvContext;
37 
38 static void decode_flush(AVCodecContext *avctx)
39 {
40  KgvContext * const c = avctx->priv_data;
41 
44 }
45 
46 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
47  AVPacket *avpkt)
48 {
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;
53  int offsets[8];
54  uint8_t *out, *prev;
55  int outcnt = 0, maxcnt;
56  int w, h, i, res;
57 
58  if (avpkt->size < 2)
59  return AVERROR_INVALIDDATA;
60 
61  w = (buf[0] + 1) * 8;
62  h = (buf[1] + 1) * 8;
63  buf += 2;
64 
65  if (avpkt->size < 2 + w*h / 513)
66  return AVERROR_INVALIDDATA;
67 
68  if (w != avctx->width || h != avctx->height) {
71  if ((res = ff_set_dimensions(avctx, w, h)) < 0)
72  return res;
73  }
74 
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) {
79  decode_flush(avctx);
80  return AVERROR(ENOMEM);
81  }
82  }
83 
84  maxcnt = w * h;
85 
86  if ((res = ff_get_buffer(avctx, frame, 0)) < 0)
87  return res;
88  out = (uint8_t*)c->frame_buffer;
89  prev = (uint8_t*)c->last_frame_buffer;
90 
91  for (i = 0; i < 8; i++)
92  offsets[i] = -1;
93 
94  while (outcnt < maxcnt && buf_end - 2 >= buf) {
95  int code = AV_RL16(buf);
96  buf += 2;
97 
98  if (!(code & 0x8000)) {
99  AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
100  outcnt++;
101  } else {
102  int count;
103 
104  if ((code & 0x6000) == 0x6000) {
105  // copy from previous frame
106  int oidx = (code >> 10) & 7;
107  int start;
108 
109  count = (code & 0x3FF) + 3;
110 
111  if (offsets[oidx] < 0) {
112  if (buf_end - 3 < buf)
113  break;
114  offsets[oidx] = AV_RL24(buf);
115  buf += 3;
116  }
117 
118  start = (outcnt + offsets[oidx]) % maxcnt;
119 
120  if (maxcnt - start < count || maxcnt - outcnt < count)
121  break;
122 
123  if (!prev) {
124  av_log(avctx, AV_LOG_ERROR,
125  "Frame reference does not exist\n");
126  break;
127  }
128 
129  memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
130  } else {
131  // copy from earlier in this frame
132  int offset = (code & 0x1FFF) + 1;
133 
134  if (!(code & 0x6000)) {
135  count = 2;
136  } else if ((code & 0x6000) == 0x2000) {
137  count = 3;
138  } else {
139  if (buf_end - 1 < buf)
140  break;
141  count = 4 + *buf++;
142  }
143 
144  if (outcnt < offset || maxcnt - outcnt < count)
145  break;
146 
147  av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
148  }
149  outcnt += count;
150  }
151  }
152 
153  if (outcnt - maxcnt)
154  av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
155 
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);
160 
161  *got_frame = 1;
162 
163  return avpkt->size;
164 }
165 
167 {
168  avctx->pix_fmt = AV_PIX_FMT_RGB555;
169 
170  return 0;
171 }
172 
174 {
175  decode_flush(avctx);
176  return 0;
177 }
178 
180  .name = "kgv1",
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),
185  .init = decode_init,
186  .close = decode_end,
187  .decode = decode_frame,
188  .flush = decode_flush,
189  .capabilities = AV_CODEC_CAP_DR1,
190 };
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:201
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
static void flush(AVCodecContext *avctx)
misc image utilities
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:196
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
int size
Definition: avcodec.h:1415
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1711
static av_cold int decode_end(AVCodecContext *avctx)
Definition: kgv1dec.c:173
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
AVCodec.
Definition: avcodec.h:3365
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:87
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:42
uint8_t
#define av_cold
Definition: attributes.h:82
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1414
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
Overlapping memcpy() implementation.
Definition: mem.c:414
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
const char * name
Name of the codec implementation.
Definition: avcodec.h:3372
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_RL24
Definition: bytestream.h:87
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
GLsizei count
Definition: opengl_enc.c:109
AVCodec ff_kgv1_decoder
Definition: kgv1dec.c:179
int width
picture width / height.
Definition: avcodec.h:1674
#define AV_WN16A(p, v)
Definition: intreadwrite.h:534
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: kgv1dec.c:46
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:232
main external API structure.
Definition: avcodec.h:1502
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1886
void * buf
Definition: avisynth_c.h:690
static void decode_flush(AVCodecContext *avctx)
Definition: kgv1dec.c:38
static av_cold int decode_init(AVCodecContext *avctx)
Definition: kgv1dec.c:166
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:215
uint16_t * frame_buffer
Definition: kgv1dec.c:34
uint16_t * last_frame_buffer
Definition: kgv1dec.c:35
common internal api header.
common internal and external API header
static double c[64]
#define AV_PIX_FMT_RGB555
Definition: pixfmt.h:356
void * priv_data
Definition: avcodec.h:1529
FILE * out
Definition: movenc.c:54
#define av_freep(p)
void INT64 start
Definition: avisynth_c.h:690
#define FFSWAP(type, a, b)
Definition: common.h:99
void av_image_copy_plane(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize, int bytewidth, int height)
Copy image plane from src to dst.
Definition: imgutils.c:338
This structure stores compressed data.
Definition: avcodec.h:1391
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:956