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