libavcodec/pcxenc.c

   1 /*
   2  * PC Paintbrush PCX (.pcx) image encoder
   3  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
   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  * PCX image encoder
  24  * @file libavcodec/pcxenc.c
  25  * @author Daniel Verkamp
  26  * @sa http://www.qzx.com/pc-gpe/pcx.txt
  27  */
  28
  29 #include "avcodec.h"
  30 #include "bytestream.h"
  31
  32 typedef struct PCXContext {
  33     AVFrame picture;
  34 } PCXContext;
  35
  36 static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };
  37
  38 static av_cold int pcx_encode_init(AVCodecContext *avctx)
  39 {
  40     PCXContext *s = avctx->priv_data;
  41
  42     avcodec_get_frame_defaults(&s->picture);
  43     avctx->coded_frame = &s->picture;
  44
  45     return 0;
  46 }
  47
  48 /**
  49  * PCX run-length encoder
  50  * @param dst output buffer
  51  * @param dst_size size of output buffer
  52  * @param src input buffer
  53  * @param src_plane_size size of one plane of input buffer in bytes
  54  * @param nplanes number of planes in input buffer
  55  * @return number of bytes written to dst or -1 on error
  56  * @bug will not work for nplanes != 1 && bpp != 8
  57  */
  58 static int pcx_rle_encode(      uint8_t *dst, int dst_size,
  59                           const uint8_t *src, int src_plane_size, int nplanes)
  60 {
  61     int p;
  62     const uint8_t *dst_start = dst;
  63
  64     // check worst-case upper bound on dst_size
  65     if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
  66         return -1;
  67
  68     for (p = 0; p < nplanes; p++) {
  69         int count = 1;
  70         const uint8_t *src_plane = src + p;
  71         const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
  72         uint8_t prev = *src_plane;
  73         src_plane += nplanes;
  74
  75         for (; ; src_plane += nplanes) {
  76             if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
  77                 // current byte is same as prev
  78                 ++count;
  79             } else {
  80                 // output prev * count
  81                 if (count != 1 || prev >= 0xC0)
  82                     *dst++ = 0xC0 | count;
  83                 *dst++ = prev;
  84
  85                 if (src_plane == src_plane_end)
  86                     break;
  87
  88                 // start new run
  89                 count = 1;
  90                 prev = *src_plane;
  91             }
  92         }
  93     }
  94
  95     return dst - dst_start;
  96 }
  97
  98 static int pcx_encode_frame(AVCodecContext *avctx,
  99                             unsigned char *buf, int buf_size, void *data)
 100 {
 101     PCXContext *s = avctx->priv_data;
 102     AVFrame *const pict = &s->picture;
 103     const uint8_t *buf_start = buf;
 104     const uint8_t *buf_end   = buf + buf_size;
 105
 106     int bpp, nplanes, i, y, line_bytes, written;
 107     const uint32_t *pal = NULL;
 108     const uint8_t *src;
 109
 110     *pict = *(AVFrame *)data;
 111     pict->pict_type = FF_I_TYPE;
 112     pict->key_frame = 1;
 113
 114     if (avctx->width > 65535 || avctx->height > 65535) {
 115         av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
 116         return -1;
 117     }
 118
 119     switch (avctx->pix_fmt) {
 120     case PIX_FMT_RGB24:
 121         bpp = 8;
 122         nplanes = 3;
 123         break;
 124     case PIX_FMT_RGB8:
 125     case PIX_FMT_BGR8:
 126     case PIX_FMT_RGB4_BYTE:
 127     case PIX_FMT_BGR4_BYTE:
 128     case PIX_FMT_GRAY8:
 129     case PIX_FMT_PAL8:
 130         bpp = 8;
 131         nplanes = 1;
 132         pal = (uint32_t *)pict->data[1];
 133         break;
 134     case PIX_FMT_MONOBLACK:
 135         bpp = 1;
 136         nplanes = 1;
 137         pal = monoblack_pal;
 138         break;
 139     default:
 140         av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
 141         return -1;
 142     }
 143
 144     line_bytes = (avctx->width * bpp + 7) >> 3;
 145     line_bytes = (line_bytes + 1) & ~1;
 146
 147     bytestream_put_byte(&buf, 10);                  // manufacturer
 148     bytestream_put_byte(&buf, 5);                   // version
 149     bytestream_put_byte(&buf, 1);                   // encoding
 150     bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane
 151     bytestream_put_le16(&buf, 0);                   // x min
 152     bytestream_put_le16(&buf, 0);                   // y min
 153     bytestream_put_le16(&buf, avctx->width - 1);    // x max
 154     bytestream_put_le16(&buf, avctx->height - 1);   // y max
 155     bytestream_put_le16(&buf, 0);                   // horizontal DPI
 156     bytestream_put_le16(&buf, 0);                   // vertical DPI
 157     for (i = 0; i < 16; i++)
 158         bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
 159     bytestream_put_byte(&buf, 0);                   // reserved
 160     bytestream_put_byte(&buf, nplanes);             // number of planes
 161     bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes
 162
 163     while (buf - buf_start < 128)
 164         *buf++= 0;
 165
 166     src = pict->data[0];
 167
 168     for (y = 0; y < avctx->height; y++) {
 169         if ((written = pcx_rle_encode(buf, buf_end - buf,
 170                                       src, line_bytes, nplanes)) < 0) {
 171             av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
 172             return -1;
 173         }
 174         buf += written;
 175         src += pict->linesize[0];
 176     }
 177
 178     if (nplanes == 1 && bpp == 8) {
 179         if (buf_end - buf < 257) {
 180             av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
 181             return -1;
 182         }
 183         bytestream_put_byte(&buf, 12);
 184         for (i = 0; i < 256; i++) {
 185             bytestream_put_be24(&buf, pal[i]);
 186         }
 187     }
 188
 189     return buf - buf_start;
 190 }
 191
 192 AVCodec pcx_encoder = {
 193     "pcx",
 194     CODEC_TYPE_VIDEO,
 195     CODEC_ID_PCX,
 196     sizeof(PCXContext),
 197     pcx_encode_init,
 198     pcx_encode_frame,
 199     NULL,
 200     .pix_fmts = (enum PixelFormat[]){
 201         PIX_FMT_RGB24,
 202         PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
 203         PIX_FMT_MONOBLACK,
 204         PIX_FMT_NONE},
 205     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
 206 };