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sgirledec.c
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1 /*
2  * Silicon Graphics RLE 8-bit video 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  * Silicon Graphics RLE 8-bit video decoder
25  * @note Data is packed in rbg323 with rle, contained in mv or mov.
26  * The algorithm and pixfmt are subtly different from SGI images.
27  */
28 
29 #include "libavutil/common.h"
30 
31 #include "avcodec.h"
32 #include "internal.h"
33 
34 typedef struct SGIRLEContext {
37 
39 {
40  SGIRLEContext *s = avctx->priv_data;
41  avctx->pix_fmt = AV_PIX_FMT_BGR8;
42  s->frame = av_frame_alloc();
43  if (!s->frame)
44  return AVERROR(ENOMEM);
45  return 0;
46 }
47 
48 /**
49  * Convert SGI RBG323 pixel into AV_PIX_FMT_BGR8
50  * SGI RGB data is packed as 8bpp, (msb)3R 2B 3G(lsb)
51  */
52 #define RBG323_TO_BGR8(x) (((x << 3) & 0xC0) | \
53  ((x << 3) & 0x38) | \
54  ((x >> 5) & 7))
55 static av_always_inline
56 void rbg323_to_bgr8(uint8_t *dst, const uint8_t *src, int size)
57 {
58  int i;
59  for (i = 0; i < size; i++)
60  dst[i] = RBG323_TO_BGR8(src[i]);
61 }
62 
63 /**
64  * @param[out] dst Destination buffer
65  * @param[in] src Source buffer
66  * @param src_size Source buffer size (bytes)
67  * @param width Width of destination buffer (pixels)
68  * @param height Height of destination buffer (pixels)
69  * @param linesize Line size of destination buffer (bytes)
70  *
71  * @return <0 on error
72  */
73 static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst,
74  const uint8_t *src, int src_size,
75  int width, int height, ptrdiff_t linesize)
76 {
77  const uint8_t *src_end = src + src_size;
78  int x = 0, y = 0;
79 
80 #define INC_XY(n) \
81  x += n; \
82  if (x >= width) { \
83  y++; \
84  if (y >= height) \
85  return 0; \
86  x = 0; \
87  }
88 
89  while (src_end - src >= 2) {
90  uint8_t v = *src++;
91  if (v > 0 && v < 0xC0) {
92  do {
93  int length = FFMIN(v, width - x);
94  if (length <= 0)
95  break;
96  memset(dst + y * linesize + x, RBG323_TO_BGR8(*src), length);
97  INC_XY(length);
98  v -= length;
99  } while (v > 0);
100  src++;
101  } else if (v >= 0xC1) {
102  v -= 0xC0;
103  do {
104  int length = FFMIN3(v, width - x, src_end - src);
105  if (src_end - src < length || length <= 0)
106  break;
107  rbg323_to_bgr8(dst + y * linesize + x, src, length);
108  INC_XY(length);
109  src += length;
110  v -= length;
111  } while (v > 0);
112  } else {
113  avpriv_request_sample(avctx, "opcode %d", v);
114  return AVERROR_PATCHWELCOME;
115  }
116  }
117  return 0;
118 }
119 
120 static int sgirle_decode_frame(AVCodecContext *avctx, void *data,
121  int *got_frame, AVPacket *avpkt)
122 {
123  SGIRLEContext *s = avctx->priv_data;
124  int ret;
125 
126  if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
127  return ret;
128 
129  ret = decode_sgirle8(avctx, s->frame->data[0], avpkt->data, avpkt->size,
130  avctx->width, avctx->height, s->frame->linesize[0]);
131  if (ret < 0)
132  return ret;
133 
134  *got_frame = 1;
135  if ((ret = av_frame_ref(data, s->frame)) < 0)
136  return ret;
137 
138  return avpkt->size;
139 }
140 
142 {
143  SGIRLEContext *s = avctx->priv_data;
144 
145  av_frame_free(&s->frame);
146 
147  return 0;
148 }
149 
151  .name = "sgirle",
152  .long_name = NULL_IF_CONFIG_SMALL("Silicon Graphics RLE 8-bit video"),
153  .type = AVMEDIA_TYPE_VIDEO,
154  .id = AV_CODEC_ID_SGIRLE,
155  .priv_data_size = sizeof(SGIRLEContext),
159  .capabilities = CODEC_CAP_DR1,
160 };