libavutil/video_hint.h

   1 /**
   2  * Copyright 2023 Elias Carotti <eliascrt at amazon dot it>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef AVUTIL_VIDEO_HINT_H
  22 #define AVUTIL_VIDEO_HINT_H
  23
  24 #include <stddef.h>
  25 #include <stdint.h>
  26 #include "libavutil/avassert.h"
  27 #include "libavutil/frame.h"
  28
  29 typedef struct AVVideoRect {
  30     uint32_t x, y;
  31     uint32_t width, height;
  32 } AVVideoRect;
  33
  34 typedef enum AVVideoHintType {
  35     /* rectangled delimit the constant areas (unchanged), default is changed */
  36     AV_VIDEO_HINT_TYPE_CONSTANT,
  37
  38     /* rectangled delimit the constant areas (changed), default is not changed */
  39     AV_VIDEO_HINT_TYPE_CHANGED,
  40 } AVVideoHintType;
  41
  42 typedef struct AVVideoHint {
  43     /**
  44      * Number of AVVideoRect present.
  45      *
  46      * May be 0, in which case no per-rectangle information is present. In this
  47      * case the values of rect_offset / rect_size are unspecified and should
  48      * not be accessed.
  49      */
  50     size_t nb_rects;
  51
  52     /**
  53      * Offset in bytes from the beginning of this structure at which the array
  54      * of AVVideoRect starts.
  55      */
  56     size_t rect_offset;
  57
  58     /**
  59      * Size in bytes of AVVideoRect.
  60      */
  61     size_t rect_size;
  62
  63     AVVideoHintType type;
  64 } AVVideoHint;
  65
  66 static av_always_inline AVVideoRect *
  67 av_video_hint_rects(const AVVideoHint *hints) {
  68     return (AVVideoRect *)((uint8_t *)hints + hints->rect_offset);
  69 }
  70
  71 static av_always_inline AVVideoRect *
  72 av_video_hint_get_rect(const AVVideoHint *hints, size_t idx) {
  73     return (AVVideoRect *)((uint8_t *)hints + hints->rect_offset + idx * hints->rect_size);
  74 }
  75
  76 /**
  77  * Allocate memory for the AVVideoHint struct along with an nb_rects-sized
  78  * arrays of AVVideoRect.
  79  *
  80  * The side data contains a list of rectangles for the portions of the frame
  81  * which changed from the last encoded one (and the remainder are assumed to be
  82  * changed), or, alternately (depending on the type parameter) the unchanged
  83  * ones (and the remaining ones are those which changed).
  84  * Macroblocks will thus be hinted either to be P_SKIP-ped or go through the
  85  * regular encoding procedure.
  86  *
  87  * It's responsibility of the caller to fill the AVRects accordingly, and to set
  88  * the proper AVVideoHintType field.
  89  *
  90  * @param out_size if non-NULL, the size in bytes of the resulting data array is
  91  *                 written here
  92  *
  93  * @return newly allocated AVVideoHint struct (must be freed by the caller using
  94  *         av_free()) on success, NULL on memory allocation failure
  95  */
  96 AVVideoHint *av_video_hint_alloc(size_t nb_rects,
  97                                  size_t *out_size);
  98
  99 /**
 100  * Same as av_video_hint_alloc(), except newly-allocated AVVideoHint is attached
 101  * as side data of type AV_FRAME_DATA_VIDEO_HINT_INFO to frame.
 102  */
 103 AVVideoHint *av_video_hint_create_side_data(AVFrame *frame,
 104                                             size_t nb_rects);
 105
 106
 107 #endif /* AVUTIL_VIDEO_HINT_H */