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
13int 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
31int 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 */
61u32 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