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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 | ||
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 | ret = ff_get_buffer(avctx, f, 0); | |
66 | if (ret < 0) | |
67 | return ret; | |
68 | ||
69 | f->pict_type = AV_PICTURE_TYPE_I; | |
70 | f->key_frame = 1; | |
71 | ||
72 | x = 0; | |
73 | y = 1; | |
74 | out_buf = f->data[0]; | |
75 | while (bytestream2_get_bytes_left(&gb) > 0) { | |
76 | int i; | |
77 | ||
78 | /* set buffer at the right position at every new line */ | |
79 | if (x == avctx->width) { | |
80 | x = 0; | |
81 | out_buf = f->data[0] + f->linesize[0] * y++; | |
82 | if (y > avctx->height) { | |
83 | av_log(avctx, AV_LOG_ERROR, | |
84 | "Ended frame decoding with %d bytes left.\n", | |
85 | bytestream2_get_bytes_left(&gb)); | |
86 | return AVERROR_INVALIDDATA; | |
87 | } | |
88 | } | |
89 | ||
90 | /* read packet and copy data */ | |
91 | count = bytestream2_get_byteu(&gb); | |
92 | if (!count || x + count > avctx->width) { | |
93 | av_log(avctx, AV_LOG_ERROR, "Invalid run length %d.\n", count); | |
94 | return AVERROR_INVALIDDATA; | |
95 | } | |
96 | ||
97 | if (avctx->pix_fmt == AV_PIX_FMT_BGR24) { | |
98 | pixel = bytestream2_get_be24(&gb); | |
99 | for (i = 0; i < count; i++) { | |
100 | AV_WB24(out_buf, pixel); | |
101 | out_buf += 3; | |
102 | } | |
103 | } else { // AV_PIX_FMT_GRAY8 | |
104 | pixel = bytestream2_get_byte(&gb); | |
105 | for (i = 0; i < count; i++) | |
106 | *out_buf++ = pixel; | |
107 | } | |
108 | ||
109 | x += i; | |
110 | } | |
111 | ||
112 | if (x != width || y != height) { | |
113 | av_log(avctx, AV_LOG_ERROR, "Picture stopped at %d,%d.\n", x, y); | |
114 | return AVERROR_INVALIDDATA; | |
115 | } | |
116 | ||
117 | *got_frame = 1; | |
118 | return avpkt->size; | |
119 | } | |
120 | ||
121 | AVCodec ff_alias_pix_decoder = { | |
122 | .name = "alias_pix", | |
123 | .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"), | |
124 | .type = AVMEDIA_TYPE_VIDEO, | |
125 | .id = AV_CODEC_ID_ALIAS_PIX, | |
126 | .decode = decode_frame, | |
127 | .capabilities = CODEC_CAP_DR1, | |
128 | }; |