pcxenc.c
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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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
29 #include "avcodec.h"
30 #include "bytestream.h"
31 #include "internal.h"
32 
33 typedef struct PCXContext {
35 } PCXContext;
36 
37 static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };
38 
40 {
41  PCXContext *s = avctx->priv_data;
42 
44  avctx->coded_frame = &s->picture;
45 
46  return 0;
47 }
48 
59 static int pcx_rle_encode( uint8_t *dst, int dst_size,
60  const uint8_t *src, int src_plane_size, int nplanes)
61 {
62  int p;
63  const uint8_t *dst_start = dst;
64 
65  // check worst-case upper bound on dst_size
66  if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
67  return -1;
68 
69  for (p = 0; p < nplanes; p++) {
70  int count = 1;
71  const uint8_t *src_plane = src + p;
72  const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
73  uint8_t prev = *src_plane;
74  src_plane += nplanes;
75 
76  for (; ; src_plane += nplanes) {
77  if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
78  // current byte is same as prev
79  ++count;
80  } else {
81  // output prev * count
82  if (count != 1 || prev >= 0xC0)
83  *dst++ = 0xC0 | count;
84  *dst++ = prev;
85 
86  if (src_plane == src_plane_end)
87  break;
88 
89  // start new run
90  count = 1;
91  prev = *src_plane;
92  }
93  }
94  }
95 
96  return dst - dst_start;
97 }
98 
99 static int pcx_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
100  const AVFrame *frame, int *got_packet)
101 {
102  PCXContext *s = avctx->priv_data;
103  AVFrame *const pict = &s->picture;
104  const uint8_t *buf_end;
105  uint8_t *buf;
106 
107  int bpp, nplanes, i, y, line_bytes, written, ret, max_pkt_size;
108  const uint32_t *pal = NULL;
109  const uint8_t *src;
110 
111  *pict = *frame;
113  pict->key_frame = 1;
114 
115  if (avctx->width > 65535 || avctx->height > 65535) {
116  av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
117  return -1;
118  }
119 
120  switch (avctx->pix_fmt) {
121  case AV_PIX_FMT_RGB24:
122  bpp = 8;
123  nplanes = 3;
124  break;
125  case AV_PIX_FMT_RGB8:
126  case AV_PIX_FMT_BGR8:
129  case AV_PIX_FMT_GRAY8:
130  case AV_PIX_FMT_PAL8:
131  bpp = 8;
132  nplanes = 1;
133  pal = (uint32_t *)pict->data[1];
134  break;
136  bpp = 1;
137  nplanes = 1;
138  pal = monoblack_pal;
139  break;
140  default:
141  av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
142  return -1;
143  }
144 
145  line_bytes = (avctx->width * bpp + 7) >> 3;
146  line_bytes = (line_bytes + 1) & ~1;
147 
148  max_pkt_size = 128 + avctx->height * 2 * line_bytes * nplanes + (pal ? 256*3 + 1 : 0);
149  if ((ret = ff_alloc_packet(pkt, max_pkt_size)) < 0) {
150  av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", max_pkt_size);
151  return ret;
152  }
153  buf = pkt->data;
154  buf_end = pkt->data + pkt->size;
155 
156  bytestream_put_byte(&buf, 10); // manufacturer
157  bytestream_put_byte(&buf, 5); // version
158  bytestream_put_byte(&buf, 1); // encoding
159  bytestream_put_byte(&buf, bpp); // bits per pixel per plane
160  bytestream_put_le16(&buf, 0); // x min
161  bytestream_put_le16(&buf, 0); // y min
162  bytestream_put_le16(&buf, avctx->width - 1); // x max
163  bytestream_put_le16(&buf, avctx->height - 1); // y max
164  bytestream_put_le16(&buf, 0); // horizontal DPI
165  bytestream_put_le16(&buf, 0); // vertical DPI
166  for (i = 0; i < 16; i++)
167  bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
168  bytestream_put_byte(&buf, 0); // reserved
169  bytestream_put_byte(&buf, nplanes); // number of planes
170  bytestream_put_le16(&buf, line_bytes); // scanline plane size in bytes
171 
172  while (buf - pkt->data < 128)
173  *buf++= 0;
174 
175  src = pict->data[0];
176 
177  for (y = 0; y < avctx->height; y++) {
178  if ((written = pcx_rle_encode(buf, buf_end - buf,
179  src, line_bytes, nplanes)) < 0) {
180  av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
181  return -1;
182  }
183  buf += written;
184  src += pict->linesize[0];
185  }
186 
187  if (nplanes == 1 && bpp == 8) {
188  if (buf_end - buf < 257) {
189  av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
190  return -1;
191  }
192  bytestream_put_byte(&buf, 12);
193  for (i = 0; i < 256; i++) {
194  bytestream_put_be24(&buf, pal[i]);
195  }
196  }
197 
198  pkt->size = buf - pkt->data;
199  pkt->flags |= AV_PKT_FLAG_KEY;
200  *got_packet = 1;
201 
202  return 0;
203 }
204 
206  .name = "pcx",
207  .type = AVMEDIA_TYPE_VIDEO,
208  .id = AV_CODEC_ID_PCX,
209  .priv_data_size = sizeof(PCXContext),
211  .encode2 = pcx_encode_frame,
212  .pix_fmts = (const enum AVPixelFormat[]){
218  },
219  .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
220 };