FFmpeg: libavcodec/xfaceenc.c Source File

FFmpeg
xfaceenc.c
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1 /*
2  * Copyright (c) 1990 James Ashton - Sydney University
3  * Copyright (c) 2012 Stefano Sabatini
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  * X-Face encoder, based on libcompface, by James Ashton.
25  */
26 
27 #include "xface.h"
28 #include "avcodec.h"
29 #include "internal.h"
30 #include "libavutil/avassert.h"
31 
32 typedef struct XFaceContext {
33   AVClass *class;
34  uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding
35   int max_line_len; ///< max line length for compressed data
36   int set_header; ///< set X-Face header in the output
37 } XFaceContext;
38 
39  static int all_same(char *bitmap, int w, int h)
40 {
41  char val, *row;
42  int x;
43 
44  val = *bitmap;
45  while (h--) {
46  row = bitmap;
47  x = w;
48  while (x--)
49  if (*(row++) != val)
50  return 0;
51  bitmap += XFACE_WIDTH;
52  }
53  return 1;
54 }
55 
56  static int all_black(char *bitmap, int w, int h)
57 {
58  if (w > 3) {
59  w /= 2;
60  h /= 2;
61  return (all_black(bitmap, w, h) && all_black(bitmap + w, w, h) &&
62  all_black(bitmap + XFACE_WIDTH * h, w, h) &&
63  all_black(bitmap + XFACE_WIDTH * h + w, w, h));
64  } else {
65  /* at least one pixel in the 2x2 grid is non-zero */
66  return *bitmap || *(bitmap + 1) ||
67  *(bitmap + XFACE_WIDTH) || *(bitmap + XFACE_WIDTH + 1);
68  }
69 }
70 
71  static int all_white(char *bitmap, int w, int h)
72 {
73  return *bitmap == 0 && all_same(bitmap, w, h);
74 }
75 
76  typedef struct {
77   ProbRange prob_ranges[XFACE_PIXELS*2];
78   int prob_ranges_idx;
79 } ProbRangesQueue;
80 
81  static inline int pq_push(ProbRangesQueue *pq, const ProbRange *p)
82 {
83  if (pq->prob_ranges_idx >= XFACE_PIXELS * 2 - 1)
84  return -1;
85  pq->prob_ranges[pq->prob_ranges_idx++] = *p;
86  return 0;
87 }
88 
89  static void push_greys(ProbRangesQueue *pq, char *bitmap, int w, int h)
90 {
91  if (w > 3) {
92  w /= 2;
93  h /= 2;
94  push_greys(pq, bitmap, w, h);
95  push_greys(pq, bitmap + w, w, h);
96  push_greys(pq, bitmap + XFACE_WIDTH * h, w, h);
97  push_greys(pq, bitmap + XFACE_WIDTH * h + w, w, h);
98  } else {
99  const ProbRange *p = ff_xface_probranges_2x2 +
100  *bitmap +
101  2 * *(bitmap + 1) +
102  4 * *(bitmap + XFACE_WIDTH) +
103  8 * *(bitmap + XFACE_WIDTH + 1);
104  pq_push(pq, p);
105  }
106 }
107 
108  static void encode_block(char *bitmap, int w, int h, int level, ProbRangesQueue *pq)
109 {
110  if (all_white(bitmap, w, h)) {
111  pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_WHITE]);
112  } else if (all_black(bitmap, w, h)) {
113  pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_BLACK]);
114  push_greys(pq, bitmap, w, h);
115  } else {
116  pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_GREY]);
117  w /= 2;
118  h /= 2;
119  level++;
120  encode_block(bitmap, w, h, level, pq);
121  encode_block(bitmap + w, w, h, level, pq);
122  encode_block(bitmap + h * XFACE_WIDTH, w, h, level, pq);
123  encode_block(bitmap + w + h * XFACE_WIDTH, w, h, level, pq);
124  }
125 }
126 
127  static av_cold int xface_encode_init(AVCodecContext *avctx)
128 {
129  avctx->coded_frame = av_frame_alloc();
130  if (!avctx->coded_frame)
131  return AVERROR(ENOMEM);
132  avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
133 
134  return 0;
135 }
136 
137  static void push_integer(BigInt *b, const ProbRange *prange)
138 {
139  uint8_t r;
140 
141  ff_big_div(b, prange->range, &r);
142  ff_big_mul(b, 0);
143  ff_big_add(b, r + prange->offset);
144 }
145 
146  static int xface_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
147  const AVFrame *frame, int *got_packet)
148 {
149  XFaceContext *xface = avctx->priv_data;
150  ProbRangesQueue pq = {{{ 0 }}, 0};
151  uint8_t bitmap_copy[XFACE_PIXELS];
152  BigInt b = {0};
153  int i, j, k, ret = 0;
154  const uint8_t *buf;
155  uint8_t *p;
156  char intbuf[XFACE_MAX_DIGITS];
157 
158  if (avctx->width || avctx->height) {
159  if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) {
160  av_log(avctx, AV_LOG_ERROR,
161  "Size value %dx%d not supported, only accepts a size of %dx%d\n",
162  avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT);
163  return AVERROR(EINVAL);
164  }
165  }
166  avctx->width = XFACE_WIDTH;
167  avctx->height = XFACE_HEIGHT;
168 
169  /* convert image from MONOWHITE to 1=black 0=white bitmap */
170  buf = frame->data[0];
171  i = j = 0;
172  do {
173  for (k = 0; k < 8; k++)
174  xface->bitmap[i++] = (buf[j]>>(7-k))&1;
175  if (++j == XFACE_WIDTH/8) {
176  buf += frame->linesize[0];
177  j = 0;
178  }
179  } while (i < XFACE_PIXELS);
180 
181  /* create a copy of bitmap */
182  memcpy(bitmap_copy, xface->bitmap, XFACE_PIXELS);
183  ff_xface_generate_face(xface->bitmap, bitmap_copy);
184 
185  encode_block(xface->bitmap, 16, 16, 0, &pq);
186  encode_block(xface->bitmap + 16, 16, 16, 0, &pq);
187  encode_block(xface->bitmap + 32, 16, 16, 0, &pq);
188  encode_block(xface->bitmap + XFACE_WIDTH * 16, 16, 16, 0, &pq);
189  encode_block(xface->bitmap + XFACE_WIDTH * 16 + 16, 16, 16, 0, &pq);
190  encode_block(xface->bitmap + XFACE_WIDTH * 16 + 32, 16, 16, 0, &pq);
191  encode_block(xface->bitmap + XFACE_WIDTH * 32, 16, 16, 0, &pq);
192  encode_block(xface->bitmap + XFACE_WIDTH * 32 + 16, 16, 16, 0, &pq);
193  encode_block(xface->bitmap + XFACE_WIDTH * 32 + 32, 16, 16, 0, &pq);
194 
195  while (pq.prob_ranges_idx > 0)
196  push_integer(&b, &pq.prob_ranges[--pq.prob_ranges_idx]);
197 
198  /* write the inverted big integer in b to intbuf */
199  i = 0;
200  av_assert0(b.nb_words < XFACE_MAX_WORDS);
201  while (b.nb_words) {
202  uint8_t r;
203  ff_big_div(&b, XFACE_PRINTS, &r);
204  av_assert0(i < sizeof(intbuf));
205  intbuf[i++] = r + XFACE_FIRST_PRINT;
206  }
207 
208  if ((ret = ff_alloc_packet2(avctx, pkt, i+2)) < 0)
209  return ret;
210 
211  /* revert the number, and close the buffer */
212  p = pkt->data;
213  while (--i >= 0)
214  *(p++) = intbuf[i];
215  *(p++) = '\n';
216  *(p++) = 0;
217 
218  pkt->flags |= AV_PKT_FLAG_KEY;
219  *got_packet = 1;
220 
221  return 0;
222 }
223 
224  static av_cold int xface_encode_close(AVCodecContext *avctx)
225 {
226  av_frame_free(&avctx->coded_frame);
227 
228  return 0;
229 }
230 
231  AVCodec ff_xface_encoder = {
232  .name = "xface",
233  .long_name = NULL_IF_CONFIG_SMALL("X-face image"),
234  .type = AVMEDIA_TYPE_VIDEO,
235  .id = AV_CODEC_ID_XFACE,
236  .priv_data_size = sizeof(XFaceContext),
237  .init = xface_encode_init,
238  .close = xface_encode_close,
239  .encode2 = xface_encode_frame,
240  .pix_fmts = (const enum PixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE },
241 };
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