linux/drivers/media/platform/coda/coda-mpeg4.c
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   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