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aliaspixenc.c
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1 /*
2  * Alias PIX image encoder
3  * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
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 #include "libavutil/intreadwrite.h"
23 
24 #include "avcodec.h"
25 #include "bytestream.h"
26 #include "internal.h"
27 
28 #define ALIAS_HEADER_SIZE 10
29 
31 {
32  avctx->coded_frame = av_frame_alloc();
33  if (!avctx->coded_frame)
34  return AVERROR(ENOMEM);
35  return 0;
36 }
37 
39  const AVFrame *frame, int *got_packet)
40 {
41  int width, height, bits_pixel, i, j, length, ret;
42  uint8_t *in_buf, *buf;
43 
45  avctx->coded_frame->key_frame = 1;
46 
47  width = avctx->width;
48  height = avctx->height;
49 
50  if (width > 65535 || height > 65535 ||
51  width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {
52  av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);
53  return AVERROR_INVALIDDATA;
54  }
55 
56  switch (avctx->pix_fmt) {
57  case AV_PIX_FMT_GRAY8:
58  bits_pixel = 8;
59  break;
60  case AV_PIX_FMT_BGR24:
61  bits_pixel = 24;
62  break;
63  default:
64  return AVERROR(EINVAL);
65  }
66 
67  length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible
68  if ((ret = ff_alloc_packet(pkt, length)) < 0) {
69  av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", length);
70  return ret;
71  }
72 
73  buf = pkt->data;
74 
75  /* Encode header. */
76  bytestream_put_be16(&buf, width);
77  bytestream_put_be16(&buf, height);
78  bytestream_put_be32(&buf, 0); /* X, Y offset */
79  bytestream_put_be16(&buf, bits_pixel);
80 
81  for (j = 0; j < height; j++) {
82  in_buf = frame->data[0] + frame->linesize[0] * j;
83  for (i = 0; i < width; ) {
84  int count = 0;
85  int pixel;
86 
87  if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
88  pixel = *in_buf;
89  while (count < 255 && count + i < width && pixel == *in_buf) {
90  count++;
91  in_buf++;
92  }
93  bytestream_put_byte(&buf, count);
94  bytestream_put_byte(&buf, pixel);
95  } else { /* AV_PIX_FMT_BGR24 */
96  pixel = AV_RB24(in_buf);
97  while (count < 255 && count + i < width &&
98  pixel == AV_RB24(in_buf)) {
99  count++;
100  in_buf += 3;
101  }
102  bytestream_put_byte(&buf, count);
103  bytestream_put_be24(&buf, pixel);
104  }
105  i += count;
106  }
107  }
108 
109  /* Total length */
110  av_shrink_packet(pkt, buf - pkt->data);
111  pkt->flags |= AV_PKT_FLAG_KEY;
112  *got_packet = 1;
113 
114  return 0;
115 }
116 
118 {
119  av_frame_free(&avctx->coded_frame);
120  return 0;
121 }
122 
124  .name = "alias_pix",
125  .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
126  .type = AVMEDIA_TYPE_VIDEO,
127  .id = AV_CODEC_ID_ALIAS_PIX,
128  .init = encode_init,
129  .encode2 = encode_frame,
130  .close = encode_close,
131  .pix_fmts = (const enum AVPixelFormat[]) {
133  },
134 };