FFmpeg
wnv1.c
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1 /*
2  * Winnov WNV1 codec
3  * Copyright (c) 2005 Konstantin Shishkov
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  * Winnov WNV1 codec.
25  */
26 
27 #define BITSTREAM_READER_LE
28 #include "avcodec.h"
29 #include "get_bits.h"
30 #include "internal.h"
31 
32 
33 static const uint16_t code_tab[16][2] = {
34  { 0x17F, 9 }, { 0xBF, 8 }, { 0x5F, 7 }, { 0x2F, 6 }, { 0x17, 5 }, { 0x0B, 4 }, { 0x005, 3 },
35  { 0x000, 1 },
36  { 0x01, 3 }, { 0x03, 4 }, { 0x07, 5 }, { 0x0F, 6 }, { 0x1F, 7 }, { 0x3F, 8 }, { 0x07F, 9 }, { 0xFF, 8 }
37 };
38 
39 #define CODE_VLC_BITS 9
40 static VLC code_vlc;
41 
42 /* returns modified base_value */
43 static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
44 {
45  int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1);
46 
47  if (v == 15)
48  return get_bits(gb, 8 - shift) << shift;
49  else
50  return base_value + ((v - 7U) << shift);
51 }
52 
53 static int decode_frame(AVCodecContext *avctx,
54  void *data, int *got_frame,
55  AVPacket *avpkt)
56 {
57  const uint8_t *buf = avpkt->data;
58  int buf_size = avpkt->size;
59  AVFrame * const p = data;
60  GetBitContext gb;
61  unsigned char *Y,*U,*V;
62  int i, j, ret, shift;
63  int prev_y = 0, prev_u = 0, prev_v = 0;
64 
65  if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
66  av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
67  return AVERROR_INVALIDDATA;
68  }
69 
70  if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
71  return ret;
72  p->key_frame = 1;
73 
74  if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)
75  return ret;
76 
77  if (buf[2] >> 4 == 6)
78  shift = 2;
79  else {
80  shift = 8 - (buf[2] >> 4);
81  if (shift > 4) {
83  "Unknown WNV1 frame header value %i",
84  buf[2] >> 4);
85  shift = 4;
86  }
87  if (shift < 1) {
89  "Unknown WNV1 frame header value %i",
90  buf[2] >> 4);
91  shift = 1;
92  }
93  }
94 
95  Y = p->data[0];
96  U = p->data[1];
97  V = p->data[2];
98  for (j = 0; j < avctx->height; j++) {
99  for (i = 0; i < avctx->width / 2; i++) {
100  Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);
101  prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);
102  prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);
103  prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);
104  }
105  Y += p->linesize[0];
106  U += p->linesize[1];
107  V += p->linesize[2];
108  }
109 
110 
111  *got_frame = 1;
112 
113  return buf_size;
114 }
115 
117 {
118  static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
119 
120  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
121 
122  code_vlc.table = code_table;
123  code_vlc.table_allocated = 1 << CODE_VLC_BITS;
124  init_vlc(&code_vlc, CODE_VLC_BITS, 16,
125  &code_tab[0][1], 4, 2,
127 
128  return 0;
129 }
130 
132  .name = "wnv1",
133  .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
134  .type = AVMEDIA_TYPE_VIDEO,
135  .id = AV_CODEC_ID_WNV1,
136  .init = decode_init,
137  .decode = decode_frame,
138  .capabilities = AV_CODEC_CAP_DR1,
139 };
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
static int shift(int a, int b)
Definition: sonic.c:82
This structure describes decoded (raw) audio or video data.
Definition: frame.h:308
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:379
#define avpriv_request_sample(...)
int size
Definition: packet.h:364
AVCodec ff_wnv1_decoder
Definition: wnv1.c:131
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:736
AVCodec.
Definition: codec.h:190
uint8_t
#define av_cold
Definition: attributes.h:88
#define height
uint8_t * data
Definition: packet.h:363
bitstream reader API header.
#define av_log(a,...)
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: wnv1.c:53
#define U(x)
Definition: vp56_arith.h:37
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
#define init_vlc(vlc, nb_bits, nb_codes,bits, bits_wrap, bits_size,codes, codes_wrap, codes_size,flags)
Definition: vlc.h:38
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
const char * name
Name of the codec implementation.
Definition: codec.h:197
Definition: vlc.h:26
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
#define CODE_VLC_BITS
Definition: wnv1.c:39
static int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
Definition: wnv1.c:43
#define Y
Definition: boxblur.h:38
int width
picture width / height.
Definition: avcodec.h:699
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:797
#define INIT_VLC_LE
Definition: vlc.h:59
int table_allocated
Definition: vlc.h:29
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:339
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:677
main external API structure.
Definition: avcodec.h:526
static VLC code_vlc
Definition: wnv1.c:40
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1879
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:322
common internal api header.
static const uint16_t code_tab[16][2]
Definition: wnv1.c:33
#define INIT_VLC_USE_NEW_STATIC
Definition: vlc.h:60
VLC_TYPE(* table)[2]
code, bits
Definition: vlc.h:28
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:386
static av_cold int decode_init(AVCodecContext *avctx)
Definition: wnv1.c:116
#define VLC_TYPE
Definition: vlc.h:24
This structure stores compressed data.
Definition: packet.h:340
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:50
int i
Definition: input.c:407
#define V
Definition: avdct.c:30