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frwu.c
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1 /*
2  * Forward Uncompressed
3  *
4  * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "bytestream.h"
25 #include "internal.h"
26 #include "libavutil/opt.h"
27 
28 typedef struct {
31 } FRWUContext;
32 
34 {
35  if (avctx->width & 1) {
36  av_log(avctx, AV_LOG_ERROR, "frwu needs even width\n");
37  return AVERROR(EINVAL);
38  }
39  avctx->pix_fmt = AV_PIX_FMT_UYVY422;
40 
41  return 0;
42 }
43 
44 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
45  AVPacket *avpkt)
46 {
47  FRWUContext *s = avctx->priv_data;
48  int field, ret;
49  AVFrame *pic = data;
50  const uint8_t *buf = avpkt->data;
51  const uint8_t *buf_end = buf + avpkt->size;
52 
53  if (avpkt->size < avctx->width * 2 * avctx->height + 4 + 2*8) {
54  av_log(avctx, AV_LOG_ERROR, "Packet is too small.\n");
55  return AVERROR_INVALIDDATA;
56  }
57  if (bytestream_get_le32(&buf) != MKTAG('F', 'R', 'W', '1')) {
58  av_log(avctx, AV_LOG_ERROR, "incorrect marker\n");
59  return AVERROR_INVALIDDATA;
60  }
61 
62  if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
63  return ret;
64 
66  pic->key_frame = 1;
67 
68  for (field = 0; field < 2; field++) {
69  int i;
70  int field_h = (avctx->height + !field) >> 1;
71  int field_size, min_field_size = avctx->width * 2 * field_h;
72  uint8_t *dst = pic->data[0];
73  if (buf_end - buf < 8)
74  return AVERROR_INVALIDDATA;
75  buf += 4; // flags? 0x80 == bottom field maybe?
76  field_size = bytestream_get_le32(&buf);
77  if (field_size < min_field_size) {
78  av_log(avctx, AV_LOG_ERROR, "Field size %i is too small (required %i)\n", field_size, min_field_size);
79  return AVERROR_INVALIDDATA;
80  }
81  if (buf_end - buf < field_size) {
82  av_log(avctx, AV_LOG_ERROR, "Packet is too small, need %i, have %i\n", field_size, (int)(buf_end - buf));
83  return AVERROR_INVALIDDATA;
84  }
85  if (field ^ s->change_field_order) {
86  dst += pic->linesize[0];
87  } else if (s->change_field_order) {
88  dst += 2 * pic->linesize[0];
89  }
90  for (i = 0; i < field_h; i++) {
91  if (s->change_field_order && field && i == field_h - 1)
92  dst = pic->data[0];
93  memcpy(dst, buf, avctx->width * 2);
94  buf += avctx->width * 2;
95  dst += pic->linesize[0] << 1;
96  }
97  buf += field_size - min_field_size;
98  }
99 
100  *got_frame = 1;
101 
102  return avpkt->size;
103 }
104 
105 static const AVOption frwu_options[] = {
106  {"change_field_order", "Change field order", offsetof(FRWUContext, change_field_order), FF_OPT_TYPE_INT,
108  {NULL}
109 };
110 
111 static const AVClass frwu_class = {
112  .class_name = "frwu Decoder",
113  .item_name = av_default_item_name,
114  .option = frwu_options,
115  .version = LIBAVUTIL_VERSION_INT,
116 };
117 
119  .name = "frwu",
120  .type = AVMEDIA_TYPE_VIDEO,
121  .id = AV_CODEC_ID_FRWU,
122  .priv_data_size = sizeof(FRWUContext),
123  .init = decode_init,
124  .decode = decode_frame,
125  .capabilities = CODEC_CAP_DR1,
126  .long_name = NULL_IF_CONFIG_SMALL("Forward Uncompressed"),
127  .priv_class = &frwu_class,
128 };