7256dc82747c15060e4612c8e238b7cc9a4cffc5
[libav.git] / libavcodec / aura.c
1 /*
2 * Aura 2 decoder
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; 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 typedef struct AuraDecodeContext {
31 AVCodecContext *avctx;
32 AVFrame frame;
33 } AuraDecodeContext;
34
35 static av_cold int aura_decode_init(AVCodecContext *avctx)
36 {
37 AuraDecodeContext *s = avctx->priv_data;
38
39 s->avctx = avctx;
40 /* width needs to be divisible by 4 for this codec to work */
41 if (avctx->width & 0x3)
42 return AVERROR(EINVAL);
43 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
44
45 return 0;
46 }
47
48 static int aura_decode_frame(AVCodecContext *avctx,
49 void *data, int *got_frame,
50 AVPacket *pkt)
51 {
52 AuraDecodeContext *s = avctx->priv_data;
53 uint8_t *Y, *U, *V;
54 uint8_t val;
55 int x, y, ret;
56 const uint8_t *buf = pkt->data;
57
58 /* prediction error tables (make it clear that they are signed values) */
59 const int8_t *delta_table = (const int8_t*)buf + 16;
60
61 if (pkt->size != 48 + avctx->height * avctx->width) {
62 av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
63 pkt->size, 48 + avctx->height * avctx->width);
64 return AVERROR_INVALIDDATA;
65 }
66
67 /* pixel data starts 48 bytes in, after 3x16-byte tables */
68 buf += 48;
69
70 if (s->frame.data[0])
71 avctx->release_buffer(avctx, &s->frame);
72
73 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
74 s->frame.reference = 0;
75 if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
76 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
77 return ret;
78 }
79
80 Y = s->frame.data[0];
81 U = s->frame.data[1];
82 V = s->frame.data[2];
83
84 /* iterate through each line in the height */
85 for (y = 0; y < avctx->height; y++) {
86 /* reset predictors */
87 val = *buf++;
88 U[0] = val & 0xF0;
89 Y[0] = val << 4;
90 val = *buf++;
91 V[0] = val & 0xF0;
92 Y[1] = Y[0] + delta_table[val & 0xF];
93 Y += 2; U++; V++;
94
95 /* iterate through the remaining pixel groups (4 pixels/group) */
96 for (x = 1; x < (avctx->width >> 1); x++) {
97 val = *buf++;
98 U[0] = U[-1] + delta_table[val >> 4];
99 Y[0] = Y[-1] + delta_table[val & 0xF];
100 val = *buf++;
101 V[0] = V[-1] + delta_table[val >> 4];
102 Y[1] = Y[ 0] + delta_table[val & 0xF];
103 Y += 2; U++; V++;
104 }
105 Y += s->frame.linesize[0] - avctx->width;
106 U += s->frame.linesize[1] - (avctx->width >> 1);
107 V += s->frame.linesize[2] - (avctx->width >> 1);
108 }
109
110 *got_frame = 1;
111 *(AVFrame*)data = s->frame;
112
113 return pkt->size;
114 }
115
116 static av_cold int aura_decode_end(AVCodecContext *avctx)
117 {
118 AuraDecodeContext *s = avctx->priv_data;
119
120 if (s->frame.data[0])
121 avctx->release_buffer(avctx, &s->frame);
122
123 return 0;
124 }
125
126 AVCodec ff_aura2_decoder = {
127 .name = "aura2",
128 .type = AVMEDIA_TYPE_VIDEO,
129 .id = AV_CODEC_ID_AURA2,
130 .priv_data_size = sizeof(AuraDecodeContext),
131 .init = aura_decode_init,
132 .close = aura_decode_end,
133 .decode = aura_decode_frame,
134 .capabilities = CODEC_CAP_DR1,
135 .long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
136 };