targaenc.c
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1 /*
2  * Targa (.tga) image encoder
3  * Copyright (c) 2007 Bobby Bingham
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 
22 #include "libavutil/intreadwrite.h"
23 #include "libavutil/pixdesc.h"
24 #include "avcodec.h"
25 #include "rle.h"
26 #include "targa.h"
27 
28 typedef struct TargaContext {
30 } TargaContext;
31 
42 static int targa_encode_rle(uint8_t *outbuf, int out_size, AVFrame *pic,
43  int bpp, int w, int h)
44 {
45  int y,ret;
46  uint8_t *out;
47 
48  out = outbuf;
49 
50  for(y = 0; y < h; y ++) {
51  ret = ff_rle_encode(out, out_size, pic->data[0] + pic->linesize[0] * y, bpp, w, 0x7f, 0, -1, 0);
52  if(ret == -1){
53  return -1;
54  }
55  out+= ret;
56  out_size -= ret;
57  }
58 
59  return out - outbuf;
60 }
61 
62 static int targa_encode_normal(uint8_t *outbuf, AVFrame *pic, int bpp, int w, int h)
63 {
64  int i, n = bpp * w;
65  uint8_t *out = outbuf;
66  uint8_t *ptr = pic->data[0];
67 
68  for(i=0; i < h; i++) {
69  memcpy(out, ptr, n);
70  out += n;
71  ptr += pic->linesize[0];
72  }
73 
74  return out - outbuf;
75 }
76 
78  unsigned char *outbuf,
79  int buf_size, void *data){
80  AVFrame *p = data;
81  int bpp, picsize, datasize = -1;
82  uint8_t *out;
83 
84  if(avctx->width > 0xffff || avctx->height > 0xffff) {
85  av_log(avctx, AV_LOG_ERROR, "image dimensions too large\n");
86  return AVERROR(EINVAL);
87  }
88  picsize = avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
89  if(buf_size < picsize + 45) {
90  av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
91  return AVERROR(EINVAL);
92  }
93 
95  p->key_frame= 1;
96 
97  /* zero out the header and only set applicable fields */
98  memset(outbuf, 0, 12);
99  AV_WL16(outbuf+12, avctx->width);
100  AV_WL16(outbuf+14, avctx->height);
101  /* image descriptor byte: origin is always top-left, bits 0-3 specify alpha */
102  outbuf[17] = 0x20 | (avctx->pix_fmt == PIX_FMT_BGRA ? 8 : 0);
103 
104  switch(avctx->pix_fmt) {
105  case PIX_FMT_GRAY8:
106  outbuf[2] = TGA_BW; /* uncompressed grayscale image */
107  outbuf[16] = 8; /* bpp */
108  break;
109  case PIX_FMT_RGB555LE:
110  outbuf[2] = TGA_RGB; /* uncompresses true-color image */
111  outbuf[16] = 16; /* bpp */
112  break;
113  case PIX_FMT_BGR24:
114  outbuf[2] = TGA_RGB; /* uncompressed true-color image */
115  outbuf[16] = 24; /* bpp */
116  break;
117  case PIX_FMT_BGRA:
118  outbuf[2] = TGA_RGB; /* uncompressed true-color image */
119  outbuf[16] = 32; /* bpp */
120  break;
121  default:
122  av_log(avctx, AV_LOG_ERROR, "Pixel format '%s' not supported.\n",
123  av_get_pix_fmt_name(avctx->pix_fmt));
124  return AVERROR(EINVAL);
125  }
126  bpp = outbuf[16] >> 3;
127 
128  out = outbuf + 18; /* skip past the header we just output */
129 
130  /* try RLE compression */
131  if (avctx->coder_type != FF_CODER_TYPE_RAW)
132  datasize = targa_encode_rle(out, picsize, p, bpp, avctx->width, avctx->height);
133 
134  /* if that worked well, mark the picture as RLE compressed */
135  if(datasize >= 0)
136  outbuf[2] |= 8;
137 
138  /* if RLE didn't make it smaller, go back to no compression */
139  else datasize = targa_encode_normal(out, p, bpp, avctx->width, avctx->height);
140 
141  out += datasize;
142 
143  /* The standard recommends including this section, even if we don't use
144  * any of the features it affords. TODO: take advantage of the pixel
145  * aspect ratio and encoder ID fields available? */
146  memcpy(out, "\0\0\0\0\0\0\0\0TRUEVISION-XFILE.", 26);
147 
148  return out + 26 - outbuf;
149 }
150 
152 {
153  TargaContext *s = avctx->priv_data;
154 
156  s->picture.key_frame= 1;
157  avctx->coded_frame= &s->picture;
158 
159  return 0;
160 }
161 
163  .name = "targa",
164  .type = AVMEDIA_TYPE_VIDEO,
165  .id = CODEC_ID_TARGA,
166  .priv_data_size = sizeof(TargaContext),
168  .encode = targa_encode_frame,
170  .long_name= NULL_IF_CONFIG_SMALL("Truevision Targa image"),
171 };