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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 "avcodec.h"
28 #include "get_bits.h"
29 #include "internal.h"
30 #include "mathops.h"
31 
32 
33 typedef struct WNV1Context {
36 
37  int shift;
39 } WNV1Context;
40 
41 static const uint16_t code_tab[16][2] = {
42  { 0x1FD, 9 }, { 0xFD, 8 }, { 0x7D, 7 }, { 0x3D, 6 }, { 0x1D, 5 }, { 0x0D, 4 }, { 0x005, 3 },
43  { 0x000, 1 },
44  { 0x004, 3 }, { 0x0C, 4 }, { 0x1C, 5 }, { 0x3C, 6 }, { 0x7C, 7 }, { 0xFC, 8 }, { 0x1FC, 9 }, { 0xFF, 8 }
45 };
46 
47 #define CODE_VLC_BITS 9
48 static VLC code_vlc;
49 
50 /* returns modified base_value */
51 static inline int wnv1_get_code(WNV1Context *w, int base_value)
52 {
53  int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
54 
55  if (v == 15)
56  return ff_reverse[get_bits(&w->gb, 8 - w->shift)];
57  else
58  return base_value + ((v - 7) << w->shift);
59 }
60 
61 static int decode_frame(AVCodecContext *avctx,
62  void *data, int *got_frame,
63  AVPacket *avpkt)
64 {
65  WNV1Context * const l = avctx->priv_data;
66  const uint8_t *buf = avpkt->data;
67  int buf_size = avpkt->size;
68  AVFrame * const p = &l->pic;
69  unsigned char *Y,*U,*V;
70  int i, j, ret;
71  int prev_y = 0, prev_u = 0, prev_v = 0;
72  uint8_t *rbuf;
73 
74  if(buf_size<=8) {
75  av_log(avctx, AV_LOG_ERROR, "buf_size %d is too small\n", buf_size);
76  return AVERROR_INVALIDDATA;
77  }
78 
79  rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
80  if (!rbuf) {
81  av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
82  return AVERROR(ENOMEM);
83  }
84 
85  if (p->data[0])
86  avctx->release_buffer(avctx, p);
87 
88  p->reference = 0;
89  if ((ret = ff_get_buffer(avctx, p)) < 0) {
90  av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
91  av_free(rbuf);
92  return ret;
93  }
94  p->key_frame = 1;
95 
96  for (i = 8; i < buf_size; i++)
97  rbuf[i] = ff_reverse[buf[i]];
98  init_get_bits(&l->gb, rbuf + 8, (buf_size - 8) * 8);
99 
100  if (buf[2] >> 4 == 6)
101  l->shift = 2;
102  else {
103  l->shift = 8 - (buf[2] >> 4);
104  if (l->shift > 4) {
105  av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
106  buf[2] >> 4);
107  l->shift = 4;
108  }
109  if (l->shift < 1) {
110  av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
111  buf[2] >> 4);
112  l->shift = 1;
113  }
114  }
115 
116  Y = p->data[0];
117  U = p->data[1];
118  V = p->data[2];
119  for (j = 0; j < avctx->height; j++) {
120  for (i = 0; i < avctx->width / 2; i++) {
121  Y[i * 2] = wnv1_get_code(l, prev_y);
122  prev_u = U[i] = wnv1_get_code(l, prev_u);
123  prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
124  prev_v = V[i] = wnv1_get_code(l, prev_v);
125  }
126  Y += p->linesize[0];
127  U += p->linesize[1];
128  V += p->linesize[2];
129  }
130 
131 
132  *got_frame = 1;
133  *(AVFrame*)data = l->pic;
134  av_free(rbuf);
135 
136  return buf_size;
137 }
138 
140 {
141  WNV1Context * const l = avctx->priv_data;
142  static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
143 
144  l->avctx = avctx;
145  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
147 
148  code_vlc.table = code_table;
149  code_vlc.table_allocated = 1 << CODE_VLC_BITS;
150  init_vlc(&code_vlc, CODE_VLC_BITS, 16,
151  &code_tab[0][1], 4, 2,
152  &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
153 
154  return 0;
155 }
156 
158 {
159  WNV1Context * const l = avctx->priv_data;
160  AVFrame *pic = &l->pic;
161 
162  if (pic->data[0])
163  avctx->release_buffer(avctx, pic);
164 
165  return 0;
166 }
167 
169  .name = "wnv1",
170  .type = AVMEDIA_TYPE_VIDEO,
171  .id = AV_CODEC_ID_WNV1,
172  .priv_data_size = sizeof(WNV1Context),
173  .init = decode_init,
174  .close = decode_end,
175  .decode = decode_frame,
176  .capabilities = CODEC_CAP_DR1,
177  .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
178 };