libavformat/evc.h

   1 /*
   2  * EVC helper functions for muxers
   3  * Copyright (c) 2022 Dawid Kozinski <d.kozinski@samsung.com>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef AVFORMAT_EVC_H
  23 #define AVFORMAT_EVC_H
  24
  25 #include <stdint.h>
  26
  27 #include "libavutil/intreadwrite.h"
  28 #include "libavutil/rational.h"
  29 #include "libavcodec/evc.h"
  30 #include "avio.h"
  31
  32 static inline int evc_get_nalu_type(const uint8_t *p, int bits_size)
  33 {
  34     int unit_type_plus1 = 0;
  35
  36     if (bits_size >= EVC_NALU_HEADER_SIZE) {
  37         // forbidden_zero_bit
  38         if ((p[0] & 0x80) != 0)   // Cannot get bitstream information. Malformed bitstream.
  39             return -1;
  40
  41         // nal_unit_type
  42         unit_type_plus1 = (p[0] >> 1) & 0x3F;
  43     }
  44
  45     return unit_type_plus1 - 1;
  46 }
  47
  48 static inline uint32_t evc_read_nal_unit_length(const uint8_t *bits, int bits_size)
  49 {
  50     if (bits_size >= EVC_NALU_LENGTH_PREFIX_SIZE)
  51         return AV_RB32(bits);
  52
  53     return 0;
  54 }
  55
  56 /**
  57  * Writes EVC sample metadata to the provided AVIOContext.
  58  *
  59  * @param pb pointer to the AVIOContext where the evc sample metadata shall be written
  60  * @param buf input data buffer
  61  * @param size size in bytes of the input data buffer
  62  * @param ps_array_completeness @see ISO/IEC 14496-15:2021 Coding of audio-visual objects - Part 15: section 12.3.3.3
  63  *
  64  * @return 0 in case of success, a negative error code in case of failure
  65  */
  66 int ff_isom_write_evcc(AVIOContext *pb, const uint8_t *data,
  67                        int size, int ps_array_completeness);
  68
  69 #endif // AVFORMAT_EVC_H