1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Coda multi-standard codec IP - MPEG-4 helper functions
4  *
5  * Copyright (C) 2019 Pengutronix, Philipp Zabel
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/videodev2.h>
10 
11 #include "coda.h"
12 
coda_mpeg4_profile(int profile_idc)13 int coda_mpeg4_profile(int profile_idc)
14 {
15 	switch (profile_idc) {
16 	case 0:
17 		return V4L2_MPEG_VIDEO_MPEG4_PROFILE_SIMPLE;
18 	case 15:
19 		return V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_SIMPLE;
20 	case 2:
21 		return V4L2_MPEG_VIDEO_MPEG4_PROFILE_CORE;
22 	case 1:
23 		return V4L2_MPEG_VIDEO_MPEG4_PROFILE_SIMPLE_SCALABLE;
24 	case 11:
25 		return V4L2_MPEG_VIDEO_MPEG4_PROFILE_ADVANCED_CODING_EFFICIENCY;
26 	default:
27 		return -EINVAL;
28 	}
29 }
30 
coda_mpeg4_level(int level_idc)31 int coda_mpeg4_level(int level_idc)
32 {
33 	switch (level_idc) {
34 	case 0:
35 		return V4L2_MPEG_VIDEO_MPEG4_LEVEL_0;
36 	case 1:
37 		return V4L2_MPEG_VIDEO_MPEG4_LEVEL_1;
38 	case 2:
39 		return V4L2_MPEG_VIDEO_MPEG4_LEVEL_2;
40 	case 3:
41 		return V4L2_MPEG_VIDEO_MPEG4_LEVEL_3;
42 	case 4:
43 		return V4L2_MPEG_VIDEO_MPEG4_LEVEL_4;
44 	case 5:
45 		return V4L2_MPEG_VIDEO_MPEG4_LEVEL_5;
46 	default:
47 		return -EINVAL;
48 	}
49 }
50 
51 /*
52  * Check if the buffer starts with the MPEG-4 visual object sequence and visual
53  * object headers, for example:
54  *
55  *   00 00 01 b0 f1
56  *   00 00 01 b5 a9 13 00 00 01 00 00 00 01 20 08
57  *               d4 8d 88 00 f5 04 04 08 14 30 3f
58  *
59  * Returns the detected header size in bytes or 0.
60  */
coda_mpeg4_parse_headers(struct coda_ctx * ctx,u8 * buf,u32 size)61 u32 coda_mpeg4_parse_headers(struct coda_ctx *ctx, u8 *buf, u32 size)
62 {
63 	static const u8 vos_start[4] = { 0x00, 0x00, 0x01, 0xb0 };
64 	static const union {
65 		u8 vo_start[4];
66 		u8 start_code_prefix[3];
67 	} u = { { 0x00, 0x00, 0x01, 0xb5 } };
68 
69 	if (size < 30 ||
70 	    memcmp(buf, vos_start, 4) != 0 ||
71 	    memcmp(buf + 5, u.vo_start, 4) != 0)
72 		return 0;
73 
74 	if (size == 30 ||
75 	    (size >= 33 && memcmp(buf + 30, u.start_code_prefix, 3) == 0))
76 		return 30;
77 
78 	if (size == 31 ||
79 	    (size >= 34 && memcmp(buf + 31, u.start_code_prefix, 3) == 0))
80 		return 31;
81 
82 	if (size == 32 ||
83 	    (size >= 35 && memcmp(buf + 32, u.start_code_prefix, 3) == 0))
84 		return 32;
85 
86 	return 0;
87 }
88