1 /*
2 * Alias PIX image decoder
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
decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)30 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
31 AVPacket *avpkt)
32 {
33 AVFrame *f = data;
34 GetByteContext gb;
35 int width, height, ret, bits_pixel, pixel;
36 uint8_t *out_buf;
37 uint8_t count;
38 int x, y;
39
40 bytestream2_init(&gb, avpkt->data, avpkt->size);
41
42 if (bytestream2_get_bytes_left(&gb) < ALIAS_HEADER_SIZE) {
43 av_log(avctx, AV_LOG_ERROR, "Header too small %d.\n", avpkt->size);
44 return AVERROR_INVALIDDATA;
45 }
46
47 width = bytestream2_get_be16u(&gb);
48 height = bytestream2_get_be16u(&gb);
49 bytestream2_skipu(&gb, 4); // obsolete X, Y offset
50 bits_pixel = bytestream2_get_be16u(&gb);
51
52 if (bits_pixel == 24)
53 avctx->pix_fmt = AV_PIX_FMT_BGR24;
54 else if (bits_pixel == 8)
55 avctx->pix_fmt = AV_PIX_FMT_GRAY8;
56 else {
57 av_log(avctx, AV_LOG_ERROR, "Invalid pixel format.\n");
58 return AVERROR_INVALIDDATA;
59 }
60
61 ret = ff_set_dimensions(avctx, width, height);
62 if (ret < 0)
63 return ret;
64
65 if (bytestream2_get_bytes_left(&gb) < width*height / 255)
66 return AVERROR_INVALIDDATA;
67
68 ret = ff_get_buffer(avctx, f, 0);
69 if (ret < 0)
70 return ret;
71
72 f->pict_type = AV_PICTURE_TYPE_I;
73 f->key_frame = 1;
74
75 x = 0;
76 y = 1;
77 out_buf = f->data[0];
78 while (bytestream2_get_bytes_left(&gb) > 0) {
79 int i;
80
81 /* set buffer at the right position at every new line */
82 if (x == avctx->width) {
83 x = 0;
84 out_buf = f->data[0] + f->linesize[0] * y++;
85 if (y > avctx->height) {
86 av_log(avctx, AV_LOG_ERROR,
87 "Ended frame decoding with %d bytes left.\n",
88 bytestream2_get_bytes_left(&gb));
89 return AVERROR_INVALIDDATA;
90 }
91 }
92
93 /* read packet and copy data */
94 count = bytestream2_get_byteu(&gb);
95 if (!count || x + count > avctx->width) {
96 av_log(avctx, AV_LOG_ERROR, "Invalid run length %d.\n", count);
97 return AVERROR_INVALIDDATA;
98 }
99
100 if (avctx->pix_fmt == AV_PIX_FMT_BGR24) {
101 pixel = bytestream2_get_be24(&gb);
102 for (i = 0; i < count; i++) {
103 AV_WB24(out_buf, pixel);
104 out_buf += 3;
105 }
106 } else { // AV_PIX_FMT_GRAY8
107 pixel = bytestream2_get_byte(&gb);
108 for (i = 0; i < count; i++)
109 *out_buf++ = pixel;
110 }
111
112 x += i;
113 }
114
115 if (x != width || y != height) {
116 av_log(avctx, AV_LOG_ERROR, "Picture stopped at %d,%d.\n", x, y);
117 return AVERROR_INVALIDDATA;
118 }
119
120 *got_frame = 1;
121 return avpkt->size;
122 }
123
124 AVCodec ff_alias_pix_decoder = {
125 .name = "alias_pix",
126 .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
127 .type = AVMEDIA_TYPE_VIDEO,
128 .id = AV_CODEC_ID_ALIAS_PIX,
129 .decode = decode_frame,
130 .capabilities = AV_CODEC_CAP_DR1,
131 };
132