path: root/libavcodec/sgirledec.c (plain)
blob: aa4f0e7e15d99c4ae8fa91ed32385c2da1ddbfaa

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	static av_cold int sgirle_decode_init(AVCodecContext *avctx)
35	{
36	avctx->pix_fmt = AV_PIX_FMT_BGR8;
37	return 0;
38	}
39
40	/**
41	* Convert SGI RBG323 pixel into AV_PIX_FMT_BGR8
42	* SGI RGB data is packed as 8bpp, (msb)3R 2B 3G(lsb)
43	*/
44	#define RBG323_TO_BGR8(x) ((((x) << 3) & 0xC0) | \
45	(((x) << 3) & 0x38) | \
46	(((x) >> 5) & 7))
47	static av_always_inline
48	void rbg323_to_bgr8(uint8_t *dst, const uint8_t *src, int size)
49	{
50	int i;
51	for (i = 0; i < size; i++)
52	dst[i] = RBG323_TO_BGR8(src[i]);
53	}
54
55	/**
56	* @param[out] dst Destination buffer
57	* @param[in] src Source buffer
58	* @param src_size Source buffer size (bytes)
59	* @param width Width of destination buffer (pixels)
60	* @param height Height of destination buffer (pixels)
61	* @param linesize Line size of destination buffer (bytes)
62	*
63	* @return <0 on error
64	*/
65	static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst,
66	const uint8_t *src, int src_size,
67	int width, int height, ptrdiff_t linesize)
68	{
69	const uint8_t *src_end = src + src_size;
70	int x = 0, y = 0;
71
72	#define INC_XY(n) \
73	x += n; \
74	if (x >= width) { \
75	y++; \
76	if (y >= height) \
77	return 0; \
78	x = 0; \
79	}
80
81	while (src_end - src >= 2) {
82	uint8_t v = *src++;
83	if (v > 0 && v < 0xC0) {
84	do {
85	int length = FFMIN(v, width - x);
86	if (length <= 0)
87	break;
88	memset(dst + y * linesize + x, RBG323_TO_BGR8(*src), length);
89	INC_XY(length);
90	v -= length;
91	} while (v > 0);
92	src++;
93	} else if (v >= 0xC1) {
94	v -= 0xC0;
95	do {
96	int length = FFMIN3(v, width - x, src_end - src);
97	if (src_end - src < length || length <= 0)
98	break;
99	rbg323_to_bgr8(dst + y * linesize + x, src, length);
100	INC_XY(length);
101	src += length;
102	v -= length;
103	} while (v > 0);
104	} else {
105	avpriv_request_sample(avctx, "opcode %d", v);
106	return AVERROR_PATCHWELCOME;
107	}
108	}
109	return 0;
110	}
111
112	static int sgirle_decode_frame(AVCodecContext *avctx, void *data,
113	int *got_frame, AVPacket *avpkt)
114	{
115	AVFrame *frame = data;
116	int ret;
117
118	if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
119	return ret;
120
121	ret = decode_sgirle8(avctx, frame->data[0], avpkt->data, avpkt->size,
122	avctx->width, avctx->height, frame->linesize[0]);
123	if (ret < 0)
124	return ret;
125
126	frame->pict_type = AV_PICTURE_TYPE_I;
127	frame->key_frame = 1;
128
129	*got_frame = 1;
130
131	return avpkt->size;
132	}
133
134	AVCodec ff_sgirle_decoder = {
135	.name = "sgirle",
136	.long_name = NULL_IF_CONFIG_SMALL("Silicon Graphics RLE 8-bit video"),
137	.type = AVMEDIA_TYPE_VIDEO,
138	.id = AV_CODEC_ID_SGIRLE,
139	.init = sgirle_decode_init,
140	.decode = sgirle_decode_frame,
141	.capabilities = AV_CODEC_CAP_DR1,
142	};
143