LXR linux/drivers/media/platform/coda/coda-mpeg2.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Coda multi-standard codec IP - MPEG-2 helper functions
   4 *
   5 * Copyright (C) 2019 Pengutronix, Philipp Zabel
   6 */
   7
   8#include <linux/kernel.h>
   9#include <linux/videodev2.h>
  10#include "coda.h"
  11
  12int coda_mpeg2_profile(int profile_idc)
  13{
  14        switch (profile_idc) {
  15        case 5:
  16                return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SIMPLE;
  17        case 4:
  18                return V4L2_MPEG_VIDEO_MPEG2_PROFILE_MAIN;
  19        case 3:
  20                return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SNR_SCALABLE;
  21        case 2:
  22                return V4L2_MPEG_VIDEO_MPEG2_PROFILE_SPATIALLY_SCALABLE;
  23        case 1:
  24                return V4L2_MPEG_VIDEO_MPEG2_PROFILE_HIGH;
  25        default:
  26                return -EINVAL;
  27        }
  28}
  29
  30int coda_mpeg2_level(int level_idc)
  31{
  32        switch (level_idc) {
  33        case 10:
  34                return V4L2_MPEG_VIDEO_MPEG2_LEVEL_LOW;
  35        case 8:
  36                return V4L2_MPEG_VIDEO_MPEG2_LEVEL_MAIN;
  37        case 6:
  38                return V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH_1440;
  39        case 4:
  40                return V4L2_MPEG_VIDEO_MPEG2_LEVEL_HIGH;
  41        default:
  42                return -EINVAL;
  43        }
  44}
  45
  46/*
  47 * Check if the buffer starts with the MPEG-2 sequence header (with or without
  48 * quantization matrix) and extension header, for example:
  49 *
  50 *   00 00 01 b3 2d 01 e0 34 08 8b a3 81
  51 *               10 11 11 12 12 12 13 13 13 13 14 14 14 14 14 15
  52 *               15 15 15 15 15 16 16 16 16 16 16 16 17 17 17 17
  53 *               17 17 17 17 18 18 18 19 18 18 18 19 1a 1a 1a 1a
  54 *               19 1b 1b 1b 1b 1b 1c 1c 1c 1c 1e 1e 1e 1f 1f 21
  55 *   00 00 01 b5 14 8a 00 01 00 00
  56 *
  57 * or:
  58 *
  59 *   00 00 01 b3 08 00 40 15 ff ff e0 28
  60 *   00 00 01 b5 14 8a 00 01 00 00
  61 *
  62 * Returns the detected header size in bytes or 0.
  63 */
  64u32 coda_mpeg2_parse_headers(struct coda_ctx *ctx, u8 *buf, u32 size)
  65{
  66        static const u8 sequence_header_start[4] = { 0x00, 0x00, 0x01, 0xb3 };
  67        static const union {
  68                u8 extension_start[4];
  69                u8 start_code_prefix[3];
  70        } u = { { 0x00, 0x00, 0x01, 0xb5 } };
  71
  72        if (size < 22 ||
  73            memcmp(buf, sequence_header_start, 4) != 0)
  74                return 0;
  75
  76        if ((size == 22 ||
  77             (size >= 25 && memcmp(buf + 22, u.start_code_prefix, 3) == 0)) &&
  78            memcmp(buf + 12, u.extension_start, 4) == 0)
  79                return 22;
  80
  81        if ((size == 86 ||
  82             (size > 89 && memcmp(buf + 86, u.start_code_prefix, 3) == 0)) &&
  83            memcmp(buf + 76, u.extension_start, 4) == 0)
  84                return 86;
  85
  86        return 0;
  87}
  88