Libav
wnv1.c
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1 /*
2  * Winnov WNV1 codec
3  * Copyright (c) 2005 Konstantin Shishkov
4  *
5  * This file is part of Libav.
6  *
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.
11  *
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.
16  *
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
20  */
21 
27 #include "avcodec.h"
28 #include "get_bits.h"
29 #include "internal.h"
30 #include "mathops.h"
31 
32 
33 typedef struct WNV1Context {
35 
36  int shift;
38 } WNV1Context;
39 
40 static const uint16_t code_tab[16][2] = {
41  { 0x1FD, 9 }, { 0xFD, 8 }, { 0x7D, 7 }, { 0x3D, 6 }, { 0x1D, 5 }, { 0x0D, 4 }, { 0x005, 3 },
42  { 0x000, 1 },
43  { 0x004, 3 }, { 0x0C, 4 }, { 0x1C, 5 }, { 0x3C, 6 }, { 0x7C, 7 }, { 0xFC, 8 }, { 0x1FC, 9 }, { 0xFF, 8 }
44 };
45 
46 #define CODE_VLC_BITS 9
47 static VLC code_vlc;
48 
49 /* returns modified base_value */
50 static inline int wnv1_get_code(WNV1Context *w, int base_value)
51 {
52  int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
53 
54  if (v == 15)
55  return ff_reverse[get_bits(&w->gb, 8 - w->shift)];
56  else
57  return base_value + ((v - 7) << w->shift);
58 }
59 
60 static int decode_frame(AVCodecContext *avctx,
61  void *data, int *got_frame,
62  AVPacket *avpkt)
63 {
64  WNV1Context * const l = avctx->priv_data;
65  const uint8_t *buf = avpkt->data;
66  int buf_size = avpkt->size;
67  AVFrame * const p = data;
68  unsigned char *Y,*U,*V;
69  int i, j, ret;
70  int prev_y = 0, prev_u = 0, prev_v = 0;
71  uint8_t *rbuf;
72 
73  if (buf_size < 8) {
74  av_log(avctx, AV_LOG_ERROR, "Packet is too short\n");
75  return AVERROR_INVALIDDATA;
76  }
77 
78  rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
79  if (!rbuf) {
80  av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
81  return AVERROR(ENOMEM);
82  }
83 
84  if ((ret = ff_get_buffer(avctx, p, 0)) < 0) {
85  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
86  av_free(rbuf);
87  return ret;
88  }
89  p->key_frame = 1;
90 
91  for (i = 8; i < buf_size; i++)
92  rbuf[i] = ff_reverse[buf[i]];
93  init_get_bits(&l->gb, rbuf + 8, (buf_size - 8) * 8);
94 
95  if (buf[2] >> 4 == 6)
96  l->shift = 2;
97  else {
98  l->shift = 8 - (buf[2] >> 4);
99  if (l->shift > 4) {
100  avpriv_request_sample(avctx,
101  "Unknown WNV1 frame header value %i",
102  buf[2] >> 4);
103  l->shift = 4;
104  }
105  if (l->shift < 1) {
106  avpriv_request_sample(avctx,
107  "Unknown WNV1 frame header value %i",
108  buf[2] >> 4);
109  l->shift = 1;
110  }
111  }
112 
113  Y = p->data[0];
114  U = p->data[1];
115  V = p->data[2];
116  for (j = 0; j < avctx->height; j++) {
117  for (i = 0; i < avctx->width / 2; i++) {
118  Y[i * 2] = wnv1_get_code(l, prev_y);
119  prev_u = U[i] = wnv1_get_code(l, prev_u);
120  prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
121  prev_v = V[i] = wnv1_get_code(l, prev_v);
122  }
123  Y += p->linesize[0];
124  U += p->linesize[1];
125  V += p->linesize[2];
126  }
127 
128 
129  *got_frame = 1;
130  av_free(rbuf);
131 
132  return buf_size;
133 }
134 
136 {
137  WNV1Context * const l = avctx->priv_data;
138  static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
139 
140  l->avctx = avctx;
141  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
142 
143  code_vlc.table = code_table;
144  code_vlc.table_allocated = 1 << CODE_VLC_BITS;
145  init_vlc(&code_vlc, CODE_VLC_BITS, 16,
146  &code_tab[0][1], 4, 2,
147  &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
148 
149  return 0;
150 }
151 
153  .name = "wnv1",
154  .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
155  .type = AVMEDIA_TYPE_VIDEO,
156  .id = AV_CODEC_ID_WNV1,
157  .priv_data_size = sizeof(WNV1Context),
158  .init = decode_init,
159  .decode = decode_frame,
160  .capabilities = CODEC_CAP_DR1,
161 };
GetBitContext gb
Definition: wnv1.c:37
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:54
This structure describes decoded (raw) audio or video data.
Definition: frame.h:135
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:240
int size
Definition: avcodec.h:974
AVCodec ff_wnv1_decoder
Definition: wnv1.c:152
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:1254
Definition: vf_drawbox.c:37
#define VLC_TYPE
Definition: get_bits.h:62
AVCodec.
Definition: avcodec.h:2796
AVCodecContext * avctx
Definition: wnv1.c:34
static int decode(MimicContext *ctx, int quality, int num_coeffs, int is_iframe)
Definition: mimic.c:275
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
uint8_t
const char * name
Name of the codec implementation.
Definition: avcodec.h:2803
#define CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:684
const char data[16]
Definition: mxf.c:70
bitstream reader API header.
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:69
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: wnv1.c:60
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:123
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:186
#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:150
Libavcodec external API header.
Definition: get_bits.h:64
#define CODE_VLC_BITS
Definition: wnv1.c:46
static int wnv1_get_code(WNV1Context *w, int base_value)
Definition: wnv1.c:50
#define FF_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:531
#define V
Definition: options_table.h:35
int width
picture width / height.
Definition: avcodec.h:1224
void * av_malloc(size_t size) av_malloc_attrib 1(1)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:62
static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE(*table)[2], int bits, int max_depth)
Parse a vlc code.
Definition: get_bits.h:522
#define INIT_VLC_USE_NEW_STATIC
Definition: get_bits.h:441
int table_allocated
Definition: get_bits.h:67
int shift
Definition: wnv1.c:36
#define av_cold
Definition: attributes.h:66
main external API structure.
Definition: avcodec.h:1050
static VLC code_vlc
Definition: wnv1.c:47
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:612
#define init_vlc(vlc, nb_bits, nb_codes,bits, bits_wrap, bits_size,codes, codes_wrap, codes_size,flags)
Definition: get_bits.h:424
uint8_t * data
Definition: avcodec.h:973
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:375
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:153
void * priv_data
Definition: avcodec.h:1092
common internal api header.
static const uint16_t code_tab[16][2]
Definition: wnv1.c:40
static av_cold int init(AVCodecParserContext *s)
Definition: h264_parser.c:499
Definition: vf_drawbox.c:37
VLC_TYPE(* table)[2]
code, bits
Definition: get_bits.h:66
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:191
static av_cold int decode_init(AVCodecContext *avctx)
Definition: wnv1.c:135
const uint8_t ff_reverse[256]
Definition: mathtables.c:72
This structure stores compressed data.
Definition: avcodec.h:950
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:141