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 "codec_internal.h"
28 #include "internal.h"
29 #include "libavutil/internal.h"
30
aura_decode_init(AVCodecContext * avctx)31 static av_cold int aura_decode_init(AVCodecContext *avctx)
32 {
33 /* width needs to be divisible by 4 for this codec to work */
34 if (avctx->width & 0x3)
35 return AVERROR(EINVAL);
36 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
37
38 return 0;
39 }
40
aura_decode_frame(AVCodecContext * avctx,AVFrame * frame,int * got_frame,AVPacket * pkt)41 static int aura_decode_frame(AVCodecContext *avctx, AVFrame *frame,
42 int *got_frame, AVPacket *pkt)
43 {
44 uint8_t *Y, *U, *V;
45 uint8_t val;
46 int x, y, ret;
47 const uint8_t *buf = pkt->data;
48
49 /* prediction error tables (make it clear that they are signed values) */
50 const int8_t *delta_table = (const int8_t*)buf + 16;
51
52 if (pkt->size != 48 + avctx->height * avctx->width) {
53 av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
54 pkt->size, 48 + avctx->height * avctx->width);
55 return AVERROR_INVALIDDATA;
56 }
57
58 /* pixel data starts 48 bytes in, after 3x16-byte tables */
59 buf += 48;
60
61 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
62 return ret;
63
64 Y = frame->data[0];
65 U = frame->data[1];
66 V = frame->data[2];
67
68 /* iterate through each line in the height */
69 for (y = 0; y < avctx->height; y++) {
70 /* reset predictors */
71 val = *buf++;
72 U[0] = val & 0xF0;
73 Y[0] = val << 4;
74 val = *buf++;
75 V[0] = val & 0xF0;
76 Y[1] = Y[0] + delta_table[val & 0xF];
77 Y += 2; U++; V++;
78
79 /* iterate through the remaining pixel groups (4 pixels/group) */
80 for (x = 1; x < (avctx->width >> 1); x++) {
81 val = *buf++;
82 U[0] = U[-1] + delta_table[val >> 4];
83 Y[0] = Y[-1] + delta_table[val & 0xF];
84 val = *buf++;
85 V[0] = V[-1] + delta_table[val >> 4];
86 Y[1] = Y[ 0] + delta_table[val & 0xF];
87 Y += 2; U++; V++;
88 }
89 Y += frame->linesize[0] - avctx->width;
90 U += frame->linesize[1] - (avctx->width >> 1);
91 V += frame->linesize[2] - (avctx->width >> 1);
92 }
93
94 *got_frame = 1;
95
96 return pkt->size;
97 }
98
99 const FFCodec ff_aura2_decoder = {
100 .p.name = "aura2",
101 .p.long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
102 .p.type = AVMEDIA_TYPE_VIDEO,
103 .p.id = AV_CODEC_ID_AURA2,
104 .init = aura_decode_init,
105 FF_CODEC_DECODE_CB(aura_decode_frame),
106 .p.capabilities = AV_CODEC_CAP_DR1,
107 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
108 };
109