FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
pcxenc.c
Go to the documentation of this file.
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  * @file
24  * PCX image encoder
25  * @author Daniel Verkamp
26  * @see http://www.qzx.com/pc-gpe/pcx.txt
27  */
28 
29 #include "avcodec.h"
30 #include "bytestream.h"
31 #include "libavutil/imgutils.h"
32 #include "internal.h"
33 
34 static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };
35 
37 {
38  avctx->coded_frame = av_frame_alloc();
39  if (!avctx->coded_frame)
40  return AVERROR(ENOMEM);
41 
43  avctx->coded_frame->key_frame = 1;
44 
45  return 0;
46 }
47 
49 {
50  av_frame_free(&avctx->coded_frame);
51  return 0;
52 }
53 
54 /**
55  * PCX run-length encoder
56  * @param dst output buffer
57  * @param dst_size size of output buffer
58  * @param src input buffer
59  * @param src_plane_size size of one plane of input buffer in bytes
60  * @param nplanes number of planes in input buffer
61  * @return number of bytes written to dst or -1 on error
62  * @bug will not work for nplanes != 1 && bpp != 8
63  */
64 static int pcx_rle_encode( uint8_t *dst, int dst_size,
65  const uint8_t *src, int src_plane_size, int nplanes)
66 {
67  int p;
68  const uint8_t *dst_start = dst;
69 
70  // check worst-case upper bound on dst_size
71  if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
72  return -1;
73 
74  for (p = 0; p < nplanes; p++) {
75  int count = 1;
76  const uint8_t *src_plane = src + p;
77  const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
78  uint8_t prev = *src_plane;
79  src_plane += nplanes;
80 
81  for (; ; src_plane += nplanes) {
82  if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
83  // current byte is same as prev
84  ++count;
85  } else {
86  // output prev * count
87  if (count != 1 || prev >= 0xC0)
88  *dst++ = 0xC0 | count;
89  *dst++ = prev;
90 
91  if (src_plane == src_plane_end)
92  break;
93 
94  // start new run
95  count = 1;
96  prev = *src_plane;
97  }
98  }
99  }
100 
101  return dst - dst_start;
102 }
103 
105  const AVFrame *frame, int *got_packet)
106 {
107  const uint8_t *buf_end;
108  uint8_t *buf;
109 
110  int bpp, nplanes, i, y, line_bytes, written, ret, max_pkt_size, sw, sh;
111  const uint32_t *pal = NULL;
112  uint32_t palette256[256];
113  const uint8_t *src;
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  bpp = 8;
131  nplanes = 1;
132  avpriv_set_systematic_pal2(palette256, avctx->pix_fmt);
133  pal = palette256;
134  break;
135  case AV_PIX_FMT_PAL8:
136  bpp = 8;
137  nplanes = 1;
138  pal = (uint32_t *)frame->data[1];
139  break;
141  bpp = 1;
142  nplanes = 1;
143  pal = monoblack_pal;
144  break;
145  default:
146  av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
147  return -1;
148  }
149 
150  line_bytes = (avctx->width * bpp + 7) >> 3;
151  line_bytes = (line_bytes + 1) & ~1;
152 
153  max_pkt_size = 128 + avctx->height * 2 * line_bytes * nplanes + (pal ? 256*3 + 1 : 0);
154  if ((ret = ff_alloc_packet2(avctx, pkt, max_pkt_size)) < 0)
155  return ret;
156  buf = pkt->data;
157  buf_end = pkt->data + pkt->size;
158 
159  sw = avctx->sample_aspect_ratio.num;
160  sh = avctx->sample_aspect_ratio.den;
161  if (sw > 0xFFFFu || sh > 0xFFFFu)
162  av_reduce(&sw, &sh, sw, sh, 0xFFFFu);
163 
164  bytestream_put_byte(&buf, 10); // manufacturer
165  bytestream_put_byte(&buf, 5); // version
166  bytestream_put_byte(&buf, 1); // encoding
167  bytestream_put_byte(&buf, bpp); // bits per pixel per plane
168  bytestream_put_le16(&buf, 0); // x min
169  bytestream_put_le16(&buf, 0); // y min
170  bytestream_put_le16(&buf, avctx->width - 1); // x max
171  bytestream_put_le16(&buf, avctx->height - 1); // y max
172  bytestream_put_le16(&buf, sw); // horizontal DPI
173  bytestream_put_le16(&buf, sh); // vertical DPI
174  for (i = 0; i < 16; i++)
175  bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
176  bytestream_put_byte(&buf, 0); // reserved
177  bytestream_put_byte(&buf, nplanes); // number of planes
178  bytestream_put_le16(&buf, line_bytes); // scanline plane size in bytes
179 
180  while (buf - pkt->data < 128)
181  *buf++= 0;
182 
183  src = frame->data[0];
184 
185  for (y = 0; y < avctx->height; y++) {
186  if ((written = pcx_rle_encode(buf, buf_end - buf,
187  src, line_bytes, nplanes)) < 0) {
188  av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
189  return -1;
190  }
191  buf += written;
192  src += frame->linesize[0];
193  }
194 
195  if (nplanes == 1 && bpp == 8) {
196  if (buf_end - buf < 257) {
197  av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
198  return -1;
199  }
200  bytestream_put_byte(&buf, 12);
201  for (i = 0; i < 256; i++) {
202  bytestream_put_be24(&buf, pal[i]);
203  }
204  }
205 
206  pkt->size = buf - pkt->data;
207  pkt->flags |= AV_PKT_FLAG_KEY;
208  *got_packet = 1;
209 
210  return 0;
211 }
212 
214  .name = "pcx",
215  .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
216  .type = AVMEDIA_TYPE_VIDEO,
217  .id = AV_CODEC_ID_PCX,
218  .init = pcx_encode_init,
219  .close = pcx_encode_close,
220  .encode2 = pcx_encode_frame,
221  .pix_fmts = (const enum AVPixelFormat[]){
227  },
228 };