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2ba45a60 DM |
1 | /* |
2 | * Aura 2 decoder | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | /** | |
22 | * @file | |
23 | * Aura 2 decoder | |
24 | */ | |
25 | ||
26 | #include "avcodec.h" | |
27 | #include "internal.h" | |
28 | #include "libavutil/internal.h" | |
29 | ||
30 | static av_cold int aura_decode_init(AVCodecContext *avctx) | |
31 | { | |
32 | /* width needs to be divisible by 4 for this codec to work */ | |
33 | if (avctx->width & 0x3) | |
34 | return AVERROR(EINVAL); | |
35 | avctx->pix_fmt = AV_PIX_FMT_YUV422P; | |
36 | ||
37 | return 0; | |
38 | } | |
39 | ||
40 | static int aura_decode_frame(AVCodecContext *avctx, | |
41 | void *data, int *got_frame, | |
42 | AVPacket *pkt) | |
43 | { | |
44 | AVFrame *frame = data; | |
45 | uint8_t *Y, *U, *V; | |
46 | uint8_t val; | |
47 | int x, y, ret; | |
48 | const uint8_t *buf = pkt->data; | |
49 | ||
50 | /* prediction error tables (make it clear that they are signed values) */ | |
51 | const int8_t *delta_table = (const int8_t*)buf + 16; | |
52 | ||
53 | if (pkt->size != 48 + avctx->height * avctx->width) { | |
54 | av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n", | |
55 | pkt->size, 48 + avctx->height * avctx->width); | |
56 | return AVERROR_INVALIDDATA; | |
57 | } | |
58 | ||
59 | /* pixel data starts 48 bytes in, after 3x16-byte tables */ | |
60 | buf += 48; | |
61 | ||
62 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) | |
63 | return ret; | |
64 | ||
65 | Y = frame->data[0]; | |
66 | U = frame->data[1]; | |
67 | V = frame->data[2]; | |
68 | ||
69 | /* iterate through each line in the height */ | |
70 | for (y = 0; y < avctx->height; y++) { | |
71 | /* reset predictors */ | |
72 | val = *buf++; | |
73 | U[0] = val & 0xF0; | |
74 | Y[0] = val << 4; | |
75 | val = *buf++; | |
76 | V[0] = val & 0xF0; | |
77 | Y[1] = Y[0] + delta_table[val & 0xF]; | |
78 | Y += 2; U++; V++; | |
79 | ||
80 | /* iterate through the remaining pixel groups (4 pixels/group) */ | |
81 | for (x = 1; x < (avctx->width >> 1); x++) { | |
82 | val = *buf++; | |
83 | U[0] = U[-1] + delta_table[val >> 4]; | |
84 | Y[0] = Y[-1] + delta_table[val & 0xF]; | |
85 | val = *buf++; | |
86 | V[0] = V[-1] + delta_table[val >> 4]; | |
87 | Y[1] = Y[ 0] + delta_table[val & 0xF]; | |
88 | Y += 2; U++; V++; | |
89 | } | |
90 | Y += frame->linesize[0] - avctx->width; | |
91 | U += frame->linesize[1] - (avctx->width >> 1); | |
92 | V += frame->linesize[2] - (avctx->width >> 1); | |
93 | } | |
94 | ||
95 | *got_frame = 1; | |
96 | ||
97 | return pkt->size; | |
98 | } | |
99 | ||
100 | AVCodec ff_aura2_decoder = { | |
101 | .name = "aura2", | |
102 | .long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"), | |
103 | .type = AVMEDIA_TYPE_VIDEO, | |
104 | .id = AV_CODEC_ID_AURA2, | |
105 | .init = aura_decode_init, | |
106 | .decode = aura_decode_frame, | |
107 | .capabilities = CODEC_CAP_DR1, | |
108 | }; |