ffmpeg/libavcodec/xfacedec.c

   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 decoder, based on libcompface, by James Ashton.
  25  */
  26
  27 #include "libavutil/pixdesc.h"
  28 #include "avcodec.h"
  29 #include "bytestream.h"
  30 #include "internal.h"
  31 #include "xface.h"
  32
  33 static int pop_integer(BigInt *b, const ProbRange *pranges)
  34 {
  35     uint8_t r;
  36     int i;
  37
  38     /* extract the last byte into r, and shift right b by 8 bits */
  39     ff_big_div(b, 0, &r);
  40
  41     i = 0;
  42     while (r < pranges->offset || r >= pranges->range + pranges->offset) {
  43         pranges++;
  44         i++;
  45     }
  46     ff_big_mul(b, pranges->range);
  47     ff_big_add(b, r - pranges->offset);
  48     return i;
  49 }
  50
  51 static void pop_greys(BigInt *b, char *bitmap, int w, int h)
  52 {
  53     if (w > 3) {
  54         w /= 2;
  55         h /= 2;
  56         pop_greys(b, bitmap,                       w, h);
  57         pop_greys(b, bitmap + w,                   w, h);
  58         pop_greys(b, bitmap + XFACE_WIDTH * h,     w, h);
  59         pop_greys(b, bitmap + XFACE_WIDTH * h + w, w, h);
  60     } else {
  61         w = pop_integer(b, ff_xface_probranges_2x2);
  62         if (w & 1) bitmap[0]               = 1;
  63         if (w & 2) bitmap[1]               = 1;
  64         if (w & 4) bitmap[XFACE_WIDTH]     = 1;
  65         if (w & 8) bitmap[XFACE_WIDTH + 1] = 1;
  66     }
  67 }
  68
  69 static void decode_block(BigInt *b, char *bitmap, int w, int h, int level)
  70 {
  71     switch (pop_integer(b, &ff_xface_probranges_per_level[level][0])) {
  72     case XFACE_COLOR_WHITE:
  73         return;
  74     case XFACE_COLOR_BLACK:
  75         pop_greys(b, bitmap, w, h);
  76         return;
  77     default:
  78         w /= 2;
  79         h /= 2;
  80         level++;
  81         decode_block(b, bitmap,                       w, h, level);
  82         decode_block(b, bitmap + w,                   w, h, level);
  83         decode_block(b, bitmap + h * XFACE_WIDTH,     w, h, level);
  84         decode_block(b, bitmap + w + h * XFACE_WIDTH, w, h, level);
  85         return;
  86     }
  87 }
  88
  89 typedef struct XFaceContext {
  90     uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding
  91 } XFaceContext;
  92
  93 static av_cold int xface_decode_init(AVCodecContext *avctx)
  94 {
  95     if (avctx->width || avctx->height) {
  96         if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) {
  97             av_log(avctx, AV_LOG_ERROR,
  98                    "Size value %dx%d not supported, only accepts a size of %dx%d\n",
  99                    avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT);
 100             return AVERROR(EINVAL);
 101         }
 102     }
 103
 104     avctx->width   = XFACE_WIDTH;
 105     avctx->height  = XFACE_HEIGHT;
 106     avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
 107
 108     return 0;
 109 }
 110
 111 static int xface_decode_frame(AVCodecContext *avctx,
 112                               void *data, int *got_frame,
 113                               AVPacket *avpkt)
 114 {
 115     XFaceContext *xface = avctx->priv_data;
 116     int ret, i, j, k;
 117     uint8_t byte;
 118     BigInt b = {0};
 119     char *buf;
 120     int64_t c;
 121     AVFrame *frame = data;
 122
 123     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 124         return ret;
 125
 126     for (i = 0, k = 0; avpkt->data[i] && i < avpkt->size; i++) {
 127         c = avpkt->data[i];
 128
 129         /* ignore invalid digits */
 130         if (c < XFACE_FIRST_PRINT || c > XFACE_LAST_PRINT)
 131             continue;
 132
 133         if (++k > XFACE_MAX_DIGITS) {
 134             av_log(avctx, AV_LOG_WARNING,
 135                    "Buffer is longer than expected, truncating at byte %d\n", i);
 136             break;
 137         }
 138         ff_big_mul(&b, XFACE_PRINTS);
 139         ff_big_add(&b, c - XFACE_FIRST_PRINT);
 140     }
 141
 142     /* decode image and put it in bitmap */
 143     memset(xface->bitmap, 0, XFACE_PIXELS);
 144     buf = xface->bitmap;
 145     decode_block(&b, buf,                         16, 16, 0);
 146     decode_block(&b, buf + 16,                    16, 16, 0);
 147     decode_block(&b, buf + 32,                    16, 16, 0);
 148     decode_block(&b, buf + XFACE_WIDTH * 16,      16, 16, 0);
 149     decode_block(&b, buf + XFACE_WIDTH * 16 + 16, 16, 16, 0);
 150     decode_block(&b, buf + XFACE_WIDTH * 16 + 32, 16, 16, 0);
 151     decode_block(&b, buf + XFACE_WIDTH * 32     , 16, 16, 0);
 152     decode_block(&b, buf + XFACE_WIDTH * 32 + 16, 16, 16, 0);
 153     decode_block(&b, buf + XFACE_WIDTH * 32 + 32, 16, 16, 0);
 154
 155     ff_xface_generate_face(xface->bitmap, xface->bitmap);
 156
 157     /* convert image from 1=black 0=white bitmap to MONOWHITE */
 158     buf = frame->data[0];
 159     for (i = 0, j = 0, k = 0, byte = 0; i < XFACE_PIXELS; i++) {
 160         byte += xface->bitmap[i];
 161         if (k == 7) {
 162             buf[j++] = byte;
 163             byte = k = 0;
 164         } else {
 165             k++;
 166             byte <<= 1;
 167         }
 168         if (j == XFACE_WIDTH/8) {
 169             j = 0;
 170             buf += frame->linesize[0];
 171         }
 172     }
 173
 174     *got_frame = 1;
 175
 176     return avpkt->size;
 177 }
 178
 179 AVCodec ff_xface_decoder = {
 180     .name           = "xface",
 181     .long_name      = NULL_IF_CONFIG_SMALL("X-face image"),
 182     .type           = AVMEDIA_TYPE_VIDEO,
 183     .id             = AV_CODEC_ID_XFACE,
 184     .priv_data_size = sizeof(XFaceContext),
 185     .init           = xface_decode_init,
 186     .decode         = xface_decode_frame,
 187     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE },
 188 };