FFmpeg: libavcodec/wnv1.c Source File

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 #include "libavutil/thread.h"
28 
29  #define BITSTREAM_READER_LE
30 #include "avcodec.h"
31 #include "get_bits.h"
32 #include "internal.h"
33 
34  static const uint8_t code_tab[16][2] = {
35  { 7, 1 }, { 8, 3 }, { 6, 3 }, { 9, 4 }, { 5, 4 }, { 10, 5 }, { 4, 5 },
36  { 11, 6 }, { 3, 6 }, { 12, 7 }, { 2, 7 }, { 13, 8 }, { 1, 8 }, { 14, 9 },
37  { 0, 9 }, { 15, 8 }
38 };
39 
40  #define CODE_VLC_BITS 9
41  static VLC code_vlc;
42 
43 /* returns modified base_value */
44  static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
45 {
46  int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1);
47 
48  if (v == 8)
49  return get_bits(gb, 8 - shift) << shift;
50  else
51  return base_value + v * (1 << shift);
52 }
53 
54  static int decode_frame(AVCodecContext *avctx,
55  void *data, int *got_frame,
56  AVPacket *avpkt)
57 {
58  const uint8_t *buf = avpkt->data;
59  int buf_size = avpkt->size;
60  AVFrame * const p = data;
61  GetBitContext gb;
62  unsigned char *Y,*U,*V;
63  int i, j, ret, shift;
64  int prev_y = 0, prev_u = 0, prev_v = 0;
65 
66  if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
67  av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
68  return AVERROR_INVALIDDATA;
69  }
70 
71  if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
72  return ret;
73  p->key_frame = 1;
74 
75  if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)
76  return ret;
77 
78  if (buf[2] >> 4 == 6)
79  shift = 2;
80  else {
81  shift = 8 - (buf[2] >> 4);
82  if (shift > 4) {
83  avpriv_request_sample(avctx,
84  "Unknown WNV1 frame header value %i",
85  buf[2] >> 4);
86  shift = 4;
87  }
88  if (shift < 1) {
89  avpriv_request_sample(avctx,
90  "Unknown WNV1 frame header value %i",
91  buf[2] >> 4);
92  shift = 1;
93  }
94  }
95 
96  Y = p->data[0];
97  U = p->data[1];
98  V = p->data[2];
99  for (j = 0; j < avctx->height; j++) {
100  for (i = 0; i < avctx->width / 2; i++) {
101  Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);
102  prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);
103  prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);
104  prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);
105  }
106  Y += p->linesize[0];
107  U += p->linesize[1];
108  V += p->linesize[2];
109  }
110 
111 
112  *got_frame = 1;
113 
114  return buf_size;
115 }
116 
117  static av_cold void wnv1_init_static(void)
118 {
119  INIT_VLC_STATIC_FROM_LENGTHS(&code_vlc, CODE_VLC_BITS, 16,
120  &code_tab[0][1], 2,
121  &code_tab[0][0], 2, 1,
122  -7, INIT_VLC_OUTPUT_LE, 1 << CODE_VLC_BITS);
123 }
124 
125  static av_cold int decode_init(AVCodecContext *avctx)
126 {
127  static AVOnce init_static_once = AV_ONCE_INIT;
128 
129  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
130 
131  ff_thread_once(&init_static_once, wnv1_init_static);
132 
133  return 0;
134 }
135 
136  const AVCodec ff_wnv1_decoder = {
137  .name = "wnv1",
138  .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
139  .type = AVMEDIA_TYPE_VIDEO,
140  .id = AV_CODEC_ID_WNV1,
141  .init = decode_init,
142  .decode = decode_frame,
143  .capabilities = AV_CODEC_CAP_DR1,
144  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
145 };
AVCodec
AVCodec.
Definition: codec.h:202
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:42
code_vlc
static VLC code_vlc
Definition: wnv1.c:41
INIT_VLC_OUTPUT_LE
#define INIT_VLC_OUTPUT_LE
Definition: vlc.h:93
thread.h
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:317
AV_CODEC_ID_WNV1
@ AV_CODEC_ID_WNV1
Definition: codec_id.h:123
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
data
const char data[16]
Definition: mxf.c:143
get_vlc2
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:798
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:338
CODE_VLC_BITS
#define CODE_VLC_BITS
Definition: wnv1.c:40
get_bits
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:380
U
#define U(x)
Definition: vp56_arith.h:37
GetBitContext
Definition: get_bits.h:62
AVFrame::key_frame
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:409
decode_init
static av_cold int decode_init(AVCodecContext *avctx)
Definition: wnv1.c:125
ff_thread_once
static int ff_thread_once(char *control, void(*routine)(void))
Definition: thread.h:175
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
av_cold
#define av_cold
Definition: attributes.h:90
init_get_bits8
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:678
get_bits.h
AV_ONCE_INIT
#define AV_ONCE_INIT
Definition: thread.h:173
INIT_VLC_STATIC_FROM_LENGTHS
#define INIT_VLC_STATIC_FROM_LENGTHS(vlc, bits, nb_codes, lens, len_wrap, symbols, symbols_wrap, symbols_size, offset, flags, static_size)
Definition: vlc.h:126
V
#define V
Definition: avdct.c:30
AVOnce
#define AVOnce
Definition: thread.h:172
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1652
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:374
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
decode_frame
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: wnv1.c:54
height
#define height
code_tab
static const uint8_t code_tab[16][2]
Definition: wnv1.c:34
Y
#define Y
Definition: boxblur.h:37
wnv1_init_static
static av_cold void wnv1_init_static(void)
Definition: wnv1.c:117
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:209
AVCodecContext::height
int height
Definition: avcodec.h:556
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:593
avcodec.h
ret
ret
Definition: filter_design.txt:187
wnv1_get_code
static int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
Definition: wnv1.c:44
AVCodecContext
main external API structure.
Definition: avcodec.h:383
VLC
Definition: vlc.h:26
shift
static int shift(int a, int b)
Definition: sonic.c:83
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AV_PIX_FMT_YUV422P
@ AV_PIX_FMT_YUV422P
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:37
ff_wnv1_decoder
const AVCodec ff_wnv1_decoder
Definition: wnv1.c:136
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:556
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, a positive or negative value, which is typically indicating the size in bytes of each pict...
Definition: frame.h:362
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
VLC::table
VLC_TYPE(* table)[2]
code, bits
Definition: vlc.h:28
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