sgienc.c
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1 /*
2  * SGI image encoder
3  * Todd Kirby <doubleshot@pacbell.net>
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 "avcodec.h"
23 #include "bytestream.h"
24 #include "sgi.h"
25 #include "rle.h"
26 
27 #define SGI_SINGLE_CHAN 2
28 #define SGI_MULTI_CHAN 3
29 
30 typedef struct SgiContext {
32 } SgiContext;
33 
35 {
36  SgiContext *s = avctx->priv_data;
37 
39  avctx->coded_frame = &s->picture;
40 
41  return 0;
42 }
43 
44 static int encode_frame(AVCodecContext *avctx, unsigned char *buf,
45  int buf_size, void *data)
46 {
47  SgiContext *s = avctx->priv_data;
48  AVFrame * const p = &s->picture;
49  uint8_t *offsettab, *lengthtab, *in_buf, *encode_buf;
50  int x, y, z, length, tablesize;
51  unsigned int width, height, depth, dimension;
52  unsigned char *orig_buf = buf, *end_buf = buf + buf_size;
53 
54  *p = *(AVFrame*)data;
56  p->key_frame = 1;
57 
58  width = avctx->width;
59  height = avctx->height;
60 
61  switch (avctx->pix_fmt) {
62  case PIX_FMT_GRAY8:
63  dimension = SGI_SINGLE_CHAN;
64  depth = SGI_GRAYSCALE;
65  break;
66  case PIX_FMT_RGB24:
67  dimension = SGI_MULTI_CHAN;
68  depth = SGI_RGB;
69  break;
70  case PIX_FMT_RGBA:
71  dimension = SGI_MULTI_CHAN;
72  depth = SGI_RGBA;
73  break;
74  default:
75  return AVERROR_INVALIDDATA;
76  }
77 
78  tablesize = depth * height * 4;
79  length = tablesize * 2 + SGI_HEADER_SIZE;
80 
81  if (buf_size < length) {
82  av_log(avctx, AV_LOG_ERROR, "buf_size too small(need %d, got %d)\n", length, buf_size);
83  return -1;
84  }
85 
86  /* Encode header. */
87  bytestream_put_be16(&buf, SGI_MAGIC);
88  bytestream_put_byte(&buf, avctx->coder_type != FF_CODER_TYPE_RAW); /* RLE 1 - VERBATIM 0*/
89  bytestream_put_byte(&buf, 1); /* bytes_per_channel */
90  bytestream_put_be16(&buf, dimension);
91  bytestream_put_be16(&buf, width);
92  bytestream_put_be16(&buf, height);
93  bytestream_put_be16(&buf, depth);
94 
95  /* The rest are constant in this implementation. */
96  bytestream_put_be32(&buf, 0L); /* pixmin */
97  bytestream_put_be32(&buf, 255L); /* pixmax */
98  bytestream_put_be32(&buf, 0L); /* dummy */
99 
100  /* name */
101  memset(buf, 0, SGI_HEADER_SIZE);
102  buf += 80;
103 
104  /* colormap */
105  bytestream_put_be32(&buf, 0L);
106 
107  /* The rest of the 512 byte header is unused. */
108  buf += 404;
109  offsettab = buf;
110 
111  if (avctx->coder_type != FF_CODER_TYPE_RAW) {
112  /* Skip RLE offset table. */
113  buf += tablesize;
114  lengthtab = buf;
115 
116  /* Skip RLE length table. */
117  buf += tablesize;
118 
119  /* Make an intermediate consecutive buffer. */
120  if (!(encode_buf = av_malloc(width)))
121  return -1;
122 
123  for (z = 0; z < depth; z++) {
124  in_buf = p->data[0] + p->linesize[0] * (height - 1) + z;
125 
126  for (y = 0; y < height; y++) {
127  bytestream_put_be32(&offsettab, buf - orig_buf);
128 
129  for (x = 0; x < width; x++)
130  encode_buf[x] = in_buf[depth * x];
131 
132  if ((length = ff_rle_encode(buf, end_buf - buf - 1, encode_buf, 1, width, 0, 0, 0x80, 0)) < 1) {
133  av_free(encode_buf);
134  return -1;
135  }
136 
137  buf += length;
138  bytestream_put_byte(&buf, 0);
139  bytestream_put_be32(&lengthtab, length + 1);
140  in_buf -= p->linesize[0];
141  }
142  }
143 
144  av_free(encode_buf);
145  } else {
146  for (z = 0; z < depth; z++) {
147  in_buf = p->data[0] + p->linesize[0] * (height - 1) + z;
148 
149  for (y = 0; y < height; y++) {
150  for (x = 0; x < width * depth; x += depth)
151  bytestream_put_byte(&buf, in_buf[x]);
152 
153  in_buf -= p->linesize[0];
154  }
155  }
156  }
157 
158  /* total length */
159  return buf - orig_buf;
160 }
161 
163  .name = "sgi",
164  .type = AVMEDIA_TYPE_VIDEO,
165  .id = CODEC_ID_SGI,
166  .priv_data_size = sizeof(SgiContext),
167  .init = encode_init,
168  .encode = encode_frame,
169  .pix_fmts= (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA, PIX_FMT_GRAY8, PIX_FMT_NONE},
170  .long_name= NULL_IF_CONFIG_SMALL("SGI image"),
171 };