FFmpeg  2.1.1
kgv1dec.c
Go to the documentation of this file.
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 {
35 } KgvContext;
36 
37 static void decode_flush(AVCodecContext *avctx)
38 {
39  KgvContext * const c = avctx->priv_data;
40 
41  av_frame_unref(c->prev);
42 }
43 
44 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
45  AVPacket *avpkt)
46 {
47  AVFrame *frame = data;
48  const uint8_t *buf = avpkt->data;
49  const uint8_t *buf_end = buf + avpkt->size;
50  KgvContext * const c = avctx->priv_data;
51  int offsets[8];
52  uint8_t *out, *prev;
53  int outcnt = 0, maxcnt;
54  int w, h, i, res;
55 
56  if (avpkt->size < 2)
57  return AVERROR_INVALIDDATA;
58 
59  w = (buf[0] + 1) * 8;
60  h = (buf[1] + 1) * 8;
61  buf += 2;
62 
63  if ((res = av_image_check_size(w, h, 0, avctx)) < 0)
64  return res;
65 
66  if (w != avctx->width || h != avctx->height) {
67  av_frame_unref(c->prev);
68  avcodec_set_dimensions(avctx, w, h);
69  }
70 
71  maxcnt = w * h;
72 
73  if ((res = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
74  return res;
75  out = frame->data[0];
76  if (c->prev->data[0]) {
77  prev = c->prev->data[0];
78  } else {
79  prev = NULL;
80  }
81 
82  for (i = 0; i < 8; i++)
83  offsets[i] = -1;
84 
85  while (outcnt < maxcnt && buf_end - 2 >= buf) {
86  int code = AV_RL16(buf);
87  buf += 2;
88 
89  if (!(code & 0x8000)) {
90  AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly
91  outcnt++;
92  } else {
93  int count;
94 
95  if ((code & 0x6000) == 0x6000) {
96  // copy from previous frame
97  int oidx = (code >> 10) & 7;
98  int start;
99 
100  count = (code & 0x3FF) + 3;
101 
102  if (offsets[oidx] < 0) {
103  if (buf_end - 3 < buf)
104  break;
105  offsets[oidx] = AV_RL24(buf);
106  buf += 3;
107  }
108 
109  start = (outcnt + offsets[oidx]) % maxcnt;
110 
111  if (maxcnt - start < count || maxcnt - outcnt < count)
112  break;
113 
114  if (!prev) {
115  av_log(avctx, AV_LOG_ERROR,
116  "Frame reference does not exist\n");
117  break;
118  }
119 
120  memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count);
121  } else {
122  // copy from earlier in this frame
123  int offset = (code & 0x1FFF) + 1;
124 
125  if (!(code & 0x6000)) {
126  count = 2;
127  } else if ((code & 0x6000) == 0x2000) {
128  count = 3;
129  } else {
130  if (buf_end - 1 < buf)
131  break;
132  count = 4 + *buf++;
133  }
134 
135  if (outcnt < offset || maxcnt - outcnt < count)
136  break;
137 
138  av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count);
139  }
140  outcnt += count;
141  }
142  }
143 
144  if (outcnt - maxcnt)
145  av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt);
146 
147  av_frame_unref(c->prev);
148  if ((res = av_frame_ref(c->prev, frame)) < 0)
149  return res;
150 
151  *got_frame = 1;
152 
153  return avpkt->size;
154 }
155 
157 {
158  KgvContext * const c = avctx->priv_data;
159 
160  avctx->pix_fmt = AV_PIX_FMT_RGB555;
161  avctx->flags |= CODEC_FLAG_EMU_EDGE;
162 
163  c->prev = av_frame_alloc();
164  if (!c->prev)
165  return AVERROR(ENOMEM);
166 
167  return 0;
168 }
169 
171 {
172  KgvContext * const c = avctx->priv_data;
173  av_frame_free(&c->prev);
174  return 0;
175 }
176 
178  .name = "kgv1",
179  .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"),
180  .type = AVMEDIA_TYPE_VIDEO,
181  .id = AV_CODEC_ID_KGV1,
182  .priv_data_size = sizeof(KgvContext),
183  .init = decode_init,
184  .close = decode_end,
185  .decode = decode_frame,
186  .flush = decode_flush,
187  .capabilities = CODEC_CAP_DR1,
188 };
This structure describes decoded (raw) audio or video data.
Definition: frame.h:96
AVFrame * prev
Definition: kgv1dec.c:34
#define AV_WN16A(p, v)
Definition: intreadwrite.h:526
#define AV_RL24(x)
Definition: intreadwrite.h:450
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
#define AV_RL16(x)
Definition: intreadwrite.h:245
void avcodec_set_dimensions(AVCodecContext *s, int width, int height)
Definition: utils.c:233
int size
Definition: avcodec.h:1064
void av_log(void *avcl, int level, const char *fmt,...) av_printf_format(3
Send the specified message to the log if the level is less than or equal to the current av_log_level...
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1342
static av_cold int decode_end(AVCodecContext *avctx)
Definition: kgv1dec.c:170
AVCodec.
Definition: avcodec.h:2922
#define av_cold
Definition: avcodec.h:653
static uint8_t * res
Definition: ffhash.c:43
uint8_t
#define AV_PIX_FMT_RGB555
Definition: avcodec.h:4938
static const uint8_t offset[511][2]
Definition: vf_uspp.c:58
const char * name
Name of the codec implementation.
Definition: avcodec.h:2929
int av_frame_ref(AVFrame *dst, AVFrame *src)
Setup a new reference to the data described by a given frame.
Definition: frame.c:247
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:742
const char data[16]
Definition: mxf.c:68
static AVFrame * frame
Definition: demuxing.c:51
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: avcodec.h:4147
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:151
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:110
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: avcodec.h:4168
int flags
CODEC_FLAG_*.
Definition: avcodec.h:1234
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:123
Libavcodec external API header.
int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx)
Check if the given dimension of an image is valid, meaning that all bytes of the image can be address...
Definition: imgutils.c:231
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
Definition: frame.c:351
AVCodec ff_kgv1_decoder
Definition: kgv1dec.c:177
int width
picture width / height.
Definition: avcodec.h:1314
static void flush(AVCodecContext *avctx)
Definition: aacdec.c:498
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: kgv1dec.c:44
main external API structure.
Definition: avcodec.h:1146
static void close(AVCodecParserContext *s)
Definition: h264_parser.c:538
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:941
void * buf
Definition: avisynth_c.h:594
static void decode_flush(AVCodecContext *avctx)
Definition: kgv1dec.c:37
uint8_t * data
Definition: avcodec.h:1063
static av_cold int decode_init(AVCodecContext *avctx)
Definition: kgv1dec.c:156
void * priv_data
Definition: avcodec.h:1182
#define CODEC_FLAG_EMU_EDGE
Don&#39;t draw edges.
Definition: avcodec.h:706
common internal api header.
static double c[64]
#define AVERROR_INVALIDDATA
uint8_t pi<< 24) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16, int16_t,(*(constint16_t *) pi >>8)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32, int32_t,(*(constint32_t *) pi >>24)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, float, av_clip_uint8(lrintf(*(constfloat *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, float, av_clip_int16(lrintf(*(constfloat *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, float, av_clipl_int32(llrintf(*(constfloat *) pi *(1U<< 31)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, double, av_clip_uint8(lrint(*(constdouble *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, double, av_clip_int16(lrint(*(constdouble *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, double, av_clipl_int32(llrint(*(constdouble *) pi *(1U<< 31))))#defineSET_CONV_FUNC_GROUP(ofmt, ifmt) staticvoidset_generic_function(AudioConvert *ac){}voidff_audio_convert_free(AudioConvert **ac){return;ff_dither_free(&(*ac) ->dc);av_freep(ac);}AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, enumAVSampleFormatout_fmt, enumAVSampleFormatin_fmt, intchannels, intsample_rate, intapply_map){AudioConvert *ac;intin_planar, out_planar;ac=av_mallocz(sizeof(*ac));returnNULL;ac->avr=avr;ac->out_fmt=out_fmt;ac->in_fmt=in_fmt;ac->channels=channels;ac->apply_map=apply_map;if(avr->dither_method!=AV_RESAMPLE_DITHER_NONE &&av_get_packed_sample_fmt(out_fmt)==AV_SAMPLE_FMT_S16 &&av_get_bytes_per_sample(in_fmt)>2){ac->dc=ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate, apply_map);if(!ac->dc){av_free(ac);returnNULL;}returnac;}in_planar=av_sample_fmt_is_planar(in_fmt);out_planar=av_sample_fmt_is_planar(out_fmt);if(in_planar==out_planar){ac->func_type=CONV_FUNC_TYPE_FLAT;ac->planes=in_planar?ac->channels:1;}elseif(in_planar) ac->func_type=CONV_FUNC_TYPE_INTERLEAVE;elseac->func_type=CONV_FUNC_TYPE_DEINTERLEAVE;set_generic_function(ac);ff_audio_convert_init_arm(ac);ff_audio_convert_init_x86(ac);returnac;}intff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in){intuse_generic=1;intlen=in->nb_samples;intp;if(ac->dc){av_dlog(ac->avr,"%dsamples-audio_convert:%sto%s(dithered)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt));returnff_convert_dither(ac-> out
#define AVERROR(e)
void INT64 INT64 count
Definition: avisynth_c.h:594
void INT64 start
Definition: avisynth_c.h:594
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
deliberately overlapping memcpy implementation
Definition: mem.c:416
static int decode(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: crystalhd.c:868
This structure stores compressed data.
Definition: avcodec.h:1040
#define AV_GET_BUFFER_FLAG_REF
The decoder will keep a reference to the frame and may reuse it later.
Definition: avcodec.h:910
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:107