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sgirledec.c
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1 /*
2  * SGI RLE 8-bit decoder
3  * Copyright (c) 2012 Peter Ross
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * SGI RLE 8-bit decoder
25  */
26 
27 #include "libavutil/intreadwrite.h"
28 #include "avcodec.h"
29 #include "bytestream.h"
30 
32 {
33  avctx->pix_fmt = AV_PIX_FMT_BGR8;
35  if (!avctx->coded_frame)
36  return AVERROR(ENOMEM);
37  return 0;
38 }
39 
40 /**
41  * Convert SGI RGB332 pixel into PIX_FMT_BGR8
42  * SGI RGB332 is packed RGB 3:3:2, 8bpp, (msb)3R 2B 3G(lsb)
43  */
44 #define RGB332_TO_BGR8(x) (((x << 3) & 0xC0) | ((x << 3) & 0x38) | ((x >> 5) & 7))
45 
47 {
48  int i;
49  for (i = 0; i < size; i++)
50  dst[i] = RGB332_TO_BGR8(src[i]);
51 }
52 
53 /**
54  * @param[out] dst Destination buffer
55  * @param[in] src Source buffer
56  * @param src_size Source buffer size (bytes)
57  * @param width Width of destination buffer (pixels)
58  * @param height Height of destination buffer (pixels)
59  * @param linesize Line size of destination buffer (bytes)
60  * @return <0 on error
61  */
62 static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst, const uint8_t *src, int src_size, int width, int height, int linesize)
63 {
64  const uint8_t *src_end = src + src_size;
65  int x = 0, y = 0;
66 
67 #define INC_XY(n) \
68  x += n; \
69  if (x >= width) { \
70  y++; \
71  if (y >= height) \
72  return 0; \
73  x = 0; \
74  }
75 
76  while (src_end - src >= 2) {
77  uint8_t v = *src++;
78  if (v > 0 && v < 0xC0) {
79  do {
80  int length = FFMIN(v, width - x);
81  memset(dst + y*linesize + x, RGB332_TO_BGR8(*src), length);
82  INC_XY(length);
83  v -= length;
84  } while (v > 0);
85  src++;
86  } else if (v >= 0xC1) {
87  v -= 0xC0;
88  do {
89  int length = FFMIN3(v, width - x, src_end - src);
90  if (src_end - src < length)
91  break;
92  memcpy_rgb332_to_bgr8(dst + y*linesize + x, src, length);
93  INC_XY(length);
94  src += length;
95  v -= length;
96  } while (v > 0);
97  } else {
98  av_log_ask_for_sample(avctx, "unknown opcode\n");
99  return AVERROR_PATCHWELCOME;
100  }
101  }
102  return 0;
103 }
104 
106  void *data, int *got_frame,
107  AVPacket *avpkt)
108 {
109  AVFrame *frame = avctx->coded_frame;
110  int ret;
111 
112  frame->reference = 3;
115  ret = avctx->reget_buffer(avctx, frame);
116  if (ret < 0) {
117  av_log (avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
118  return ret;
119  }
120 
121  ret = decode_sgirle8(avctx, frame->data[0], avpkt->data, avpkt->size, avctx->width, avctx->height, frame->linesize[0]);
122  if (ret < 0)
123  return ret;
124 
125  *got_frame = 1;
126  *(AVFrame*)data = *frame;
127 
128  return avpkt->size;
129 }
130 
132 {
133  if (avctx->coded_frame->data[0])
134  avctx->release_buffer(avctx, avctx->coded_frame);
135  av_freep(&avctx->coded_frame);
136  return 0;
137 }
138 
140  .name = "sgirle",
141  .type = AVMEDIA_TYPE_VIDEO,
142  .id = AV_CODEC_ID_SGIRLE,
143  .init = sgirle_decode_init,
144  .close = sgirle_decode_end,
145  .decode = sgirle_decode_frame,
146  .capabilities = CODEC_CAP_DR1,
147  .long_name = NULL_IF_CONFIG_SMALL("SGI RLE 8-bit"),
148 };