FFmpeg
wnv1.c
Go to the documentation of this file.
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 "avcodec.h"
28 #include "get_bits.h"
29 #include "internal.h"
30 #include "mathops.h"
31 
32 
33 typedef struct WNV1Context {
34  int shift;
36 } WNV1Context;
37 
38 static const uint16_t code_tab[16][2] = {
39  { 0x1FD, 9 }, { 0xFD, 8 }, { 0x7D, 7 }, { 0x3D, 6 }, { 0x1D, 5 }, { 0x0D, 4 }, { 0x005, 3 },
40  { 0x000, 1 },
41  { 0x004, 3 }, { 0x0C, 4 }, { 0x1C, 5 }, { 0x3C, 6 }, { 0x7C, 7 }, { 0xFC, 8 }, { 0x1FC, 9 }, { 0xFF, 8 }
42 };
43 
44 #define CODE_VLC_BITS 9
45 static VLC code_vlc;
46 
47 /* returns modified base_value */
48 static inline int wnv1_get_code(WNV1Context *w, int base_value)
49 {
50  int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
51 
52  if (v == 15)
53  return ff_reverse[get_bits(&w->gb, 8 - w->shift)];
54  else
55  return base_value + ((v - 7U) << w->shift);
56 }
57 
58 static int decode_frame(AVCodecContext *avctx,
59  void *data, int *got_frame,
60  AVPacket *avpkt)
61 {
62  WNV1Context * const l = avctx->priv_data;
63  const uint8_t *buf = avpkt->data;
64  int buf_size = avpkt->size;
65  AVFrame * const p = data;
66  unsigned char *Y,*U,*V;
67  int i, j, ret;
68  int prev_y = 0, prev_u = 0, prev_v = 0;
69  uint8_t *rbuf;
70 
71  if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
72  av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
73  return AVERROR_INVALIDDATA;
74  }
75 
76  rbuf = av_malloc(buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
77  if (!rbuf) {
78  av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
79  return AVERROR(ENOMEM);
80  }
81  memset(rbuf + buf_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
82 
83  if ((ret = ff_get_buffer(avctx, p, 0)) < 0) {
84  av_free(rbuf);
85  return ret;
86  }
87  p->key_frame = 1;
88 
89  for (i = 8; i < buf_size; i++)
90  rbuf[i] = ff_reverse[buf[i]];
91 
92  if ((ret = init_get_bits8(&l->gb, rbuf + 8, buf_size - 8)) < 0)
93  return ret;
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  static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
138 
139  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
140 
141  code_vlc.table = code_table;
142  code_vlc.table_allocated = 1 << CODE_VLC_BITS;
143  init_vlc(&code_vlc, CODE_VLC_BITS, 16,
144  &code_tab[0][1], 4, 2,
145  &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
146 
147  return 0;
148 }
149 
151  .name = "wnv1",
152  .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
153  .type = AVMEDIA_TYPE_VIDEO,
154  .id = AV_CODEC_ID_WNV1,
155  .priv_data_size = sizeof(WNV1Context),
156  .init = decode_init,
157  .decode = decode_frame,
158  .capabilities = AV_CODEC_CAP_DR1,
159 };
GetBitContext gb
Definition: wnv1.c:35
#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:295
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
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
const uint8_t ff_reverse[256]
Definition: reverse.c:23
#define avpriv_request_sample(...)
int size
Definition: avcodec.h:1481
AVCodec ff_wnv1_decoder
Definition: wnv1.c:150
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1778
AVCodec.
Definition: avcodec.h:3492
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
uint8_t
#define av_cold
Definition: attributes.h:82
#define av_malloc(s)
#define height
uint8_t * data
Definition: avcodec.h:1480
bitstream reader API header.
#define av_log(a,...)
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: wnv1.c:58
#define U(x)
Definition: vp56_arith.h:37
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#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:186
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
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:44
static int wnv1_get_code(WNV1Context *w, int base_value)
Definition: wnv1.c:48
#define Y
Definition: boxblur.h:38
int width
picture width / height.
Definition: avcodec.h:1741
uint8_t w
Definition: llviddspenc.c:38
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
int table_allocated
Definition: vlc.h:29
int shift
Definition: wnv1.c:34
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
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:1568
static VLC code_vlc
Definition: wnv1.c:45
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1968
void * buf
Definition: avisynth_c.h:766
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
common internal api header.
static const uint16_t code_tab[16][2]
Definition: wnv1.c:38
#define INIT_VLC_USE_NEW_STATIC
Definition: vlc.h:55
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:793
void * priv_data
Definition: avcodec.h:1595
#define av_free(p)
VLC_TYPE(* table)[2]
code, bits
Definition: vlc.h:28
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
static av_cold int decode_init(AVCodecContext *avctx)
Definition: wnv1.c:135
#define VLC_TYPE
Definition: vlc.h:24
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: avcodec.h:1457
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984
#define V
Definition: avdct.c:30