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yuv4dec.c
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1 /*
2  * libquicktime yuv4 decoder
3  *
4  * Copyright (c) 2011 Carl Eugen Hoyos
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 "internal.h"
25 
27 {
28  avctx->pix_fmt = AV_PIX_FMT_YUV420P;
29 
31 
32  if (!avctx->coded_frame) {
33  av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n");
34  return AVERROR(ENOMEM);
35  }
36 
37  return 0;
38 }
39 
40 static int yuv4_decode_frame(AVCodecContext *avctx, void *data,
41  int *got_frame, AVPacket *avpkt)
42 {
43  AVFrame *pic = avctx->coded_frame;
44  const uint8_t *src = avpkt->data;
45  uint8_t *y, *u, *v;
46  int i, j;
47 
48  if (pic->data[0])
49  avctx->release_buffer(avctx, pic);
50 
51  if (avpkt->size < 6 * (avctx->width + 1 >> 1) * (avctx->height + 1 >> 1)) {
52  av_log(avctx, AV_LOG_ERROR, "Insufficient input data.\n");
53  return AVERROR(EINVAL);
54  }
55 
56  pic->reference = 0;
57 
58  if (ff_get_buffer(avctx, pic) < 0) {
59  av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
60  return AVERROR(ENOMEM);
61  }
62 
63  pic->key_frame = 1;
65 
66  y = pic->data[0];
67  u = pic->data[1];
68  v = pic->data[2];
69 
70  for (i = 0; i < (avctx->height + 1) >> 1; i++) {
71  for (j = 0; j < (avctx->width + 1) >> 1; j++) {
72  u[j] = *src++ ^ 0x80;
73  v[j] = *src++ ^ 0x80;
74  y[ 2 * j ] = *src++;
75  y[ 2 * j + 1] = *src++;
76  y[pic->linesize[0] + 2 * j ] = *src++;
77  y[pic->linesize[0] + 2 * j + 1] = *src++;
78  }
79 
80  y += 2 * pic->linesize[0];
81  u += pic->linesize[1];
82  v += pic->linesize[2];
83  }
84 
85  *got_frame = 1;
86  *(AVFrame *)data = *pic;
87 
88  return avpkt->size;
89 }
90 
92 {
93  if (avctx->coded_frame->data[0])
94  avctx->release_buffer(avctx, avctx->coded_frame);
95 
96  av_freep(&avctx->coded_frame);
97 
98  return 0;
99 }
100 
102  .name = "yuv4",
103  .type = AVMEDIA_TYPE_VIDEO,
104  .id = AV_CODEC_ID_YUV4,
105  .init = yuv4_decode_init,
106  .decode = yuv4_decode_frame,
107  .close = yuv4_decode_close,
108  .capabilities = CODEC_CAP_DR1,
109  .long_name = NULL_IF_CONFIG_SMALL("Uncompressed packed 4:2:0"),
110 };