cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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coda-mpeg4.c (2007B)

      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}