f7830102230ea0c0118f87df5881796bf5a48238
[libav.git] / libavcodec / aura.c
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 libavcodec/aura.c
23 * Aura 2 decoder
24 */
25
26 #include "avcodec.h"
27
28 typedef struct AuraDecodeContext {
29 AVCodecContext *avctx;
30 AVFrame frame;
31 } AuraDecodeContext;
32
33 static av_cold int aura_decode_init(AVCodecContext *avctx)
34 {
35 AuraDecodeContext *s = avctx->priv_data;
36
37 s->avctx = avctx;
38 /* width needs to be divisible by 4 for this codec to work */
39 if (avctx->width & 0x3)
40 return -1;
41 avctx->pix_fmt = PIX_FMT_YUV422P;
42
43 return 0;
44 }
45
46 static int aura_decode_frame(AVCodecContext *avctx,
47 void *data, int *data_size,
48 AVPacket *pkt)
49 {
50 AuraDecodeContext *s=avctx->priv_data;
51
52 uint8_t *Y, *U, *V;
53 uint8_t val;
54 int x, y;
55 const uint8_t *buf = pkt->data;
56
57 /* prediction error tables (make it clear that they are signed values) */
58 const int8_t *delta_table = (const int8_t*)buf + 16;
59
60 if (pkt->size != 48 + avctx->height * avctx->width) {
61 av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
62 pkt->size, 48 + avctx->height * avctx->width);
63 return -1;
64 }
65
66 /* pixel data starts 48 bytes in, after 3x16-byte tables */
67 buf += 48;
68
69 if(s->frame.data[0])
70 avctx->release_buffer(avctx, &s->frame);
71
72 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
73 s->frame.reference = 0;
74 if(avctx->get_buffer(avctx, &s->frame) < 0) {
75 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
76 return -1;
77 }
78
79 Y = s->frame.data[0];
80 U = s->frame.data[1];
81 V = s->frame.data[2];
82
83 /* iterate through each line in the height */
84 for (y = 0; y < avctx->height; y++) {
85 /* reset predictors */
86 val = *buf++;
87 U[0] = val & 0xF0;
88 Y[0] = val << 4;
89 val = *buf++;
90 V[0] = val & 0xF0;
91 Y[1] = Y[0] + delta_table[val & 0xF];
92 Y += 2; U++; V++;
93
94 /* iterate through the remaining pixel groups (4 pixels/group) */
95 for (x = 1; x < (avctx->width >> 1); x++) {
96 val = *buf++;
97 U[0] = U[-1] + delta_table[val >> 4];
98 Y[0] = Y[-1] + delta_table[val & 0xF];
99 val = *buf++;
100 V[0] = V[-1] + delta_table[val >> 4];
101 Y[1] = Y[ 0] + delta_table[val & 0xF];
102 Y += 2; U++; V++;
103 }
104 Y += s->frame.linesize[0] - avctx->width;
105 U += s->frame.linesize[1] - (avctx->width >> 1);
106 V += s->frame.linesize[2] - (avctx->width >> 1);
107 }
108
109 *data_size=sizeof(AVFrame);
110 *(AVFrame*)data= s->frame;
111
112 return pkt->size;
113 }
114
115 static av_cold int aura_decode_end(AVCodecContext *avctx)
116 {
117 AuraDecodeContext *s = avctx->priv_data;
118
119 if (s->frame.data[0])
120 avctx->release_buffer(avctx, &s->frame);
121
122 return 0;
123 }
124
125 AVCodec aura2_decoder = {
126 "aura2",
127 CODEC_TYPE_VIDEO,
128 CODEC_ID_AURA2,
129 sizeof(AuraDecodeContext),
130 aura_decode_init,
131 NULL,
132 aura_decode_end,
133 aura_decode_frame,
134 CODEC_CAP_DR1,
135 NULL,
136 .long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
137 };
138