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
aura_decode_init(AVCodecContext * avctx)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
aura_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * pkt)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 = AV_CODEC_CAP_DR1,
108 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
109 };
110