dxtory.c
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1 /*
2  * Dxtory decoder
3  *
4  * Copyright (c) 2011 Konstantin Shishkov
5  *
6  * This file is part of Libav.
7  *
8  * Libav is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * Libav is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "avcodec.h"
24 #include "libavutil/intreadwrite.h"
25 
27 {
28  avctx->pix_fmt = PIX_FMT_YUV420P;
30  if (!avctx->coded_frame)
31  return AVERROR(ENOMEM);
32 
33  return 0;
34 }
35 
36 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
37  AVPacket *avpkt)
38 {
39  int h, w;
40  AVFrame *pic = avctx->coded_frame;
41  const uint8_t *src = avpkt->data;
42  uint8_t *Y1, *Y2, *U, *V;
43  int ret;
44 
45  if (pic->data[0])
46  avctx->release_buffer(avctx, pic);
47 
48  if (avpkt->size < avctx->width * avctx->height * 3 / 2 + 16) {
49  av_log(avctx, AV_LOG_ERROR, "packet too small\n");
50  return AVERROR_INVALIDDATA;
51  }
52 
53  pic->reference = 0;
54  if ((ret = avctx->get_buffer(avctx, pic)) < 0)
55  return ret;
56 
58  pic->key_frame = 1;
59 
60  if (AV_RL32(src) != 0x01000002) {
61  av_log_ask_for_sample(avctx, "Unknown frame header %X\n", AV_RL32(src));
62  return AVERROR_PATCHWELCOME;
63  }
64  src += 16;
65 
66  Y1 = pic->data[0];
67  Y2 = pic->data[0] + pic->linesize[0];
68  U = pic->data[1];
69  V = pic->data[2];
70  for (h = 0; h < avctx->height; h += 2) {
71  for (w = 0; w < avctx->width; w += 2) {
72  AV_WN16A(Y1 + w, AV_RN16A(src));
73  AV_WN16A(Y2 + w, AV_RN16A(src + 2));
74  U[w >> 1] = src[4] + 0x80;
75  V[w >> 1] = src[5] + 0x80;
76  src += 6;
77  }
78  Y1 += pic->linesize[0] << 1;
79  Y2 += pic->linesize[0] << 1;
80  U += pic->linesize[1];
81  V += pic->linesize[2];
82  }
83 
84  *data_size = sizeof(AVFrame);
85  *(AVFrame*)data = *pic;
86 
87  return avpkt->size;
88 }
89 
91 {
92  AVFrame *pic = avctx->coded_frame;
93  if (pic->data[0])
94  avctx->release_buffer(avctx, pic);
95  av_freep(&avctx->coded_frame);
96 
97  return 0;
98 }
99 
101  .name = "dxtory",
102  .long_name = NULL_IF_CONFIG_SMALL("Dxtory"),
103  .type = AVMEDIA_TYPE_VIDEO,
104  .id = CODEC_ID_DXTORY,
105  .init = decode_init,
106  .close = decode_close,
107  .decode = decode_frame,
108  .capabilities = CODEC_CAP_DR1,
109 };