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FFmpeg/libavfilter/vf_eq.h
Anton Khirnov 27f8c9b27b lavu/frame: deprecate AVFrame.pkt_{pos,size}
These fields are supposed to store information about the packet the
frame was decoded from, specifically the byte offset it was stored at
and its size.

However,
- the fields are highly ad-hoc - there is no strong reason why
  specifically those (and not any other) packet properties should have a
  dedicated field in AVFrame; unlike e.g. the timestamps, there is no
  fundamental link between coded packet offset/size and decoded frames
- they only make sense for frames produced by decoding demuxed packets,
  and even then it is not always the case that the encoded data was
  stored in the file as a contiguous sequence of bytes (in order for pos
  to be well-defined)
- pkt_pos was added without much explanation, apparently to allow
  passthrough of this information through lavfi in order to handle byte
  seeking in ffplay. That is now implemented using arbitrary user data
  passthrough in AVFrame.opaque_ref.
- several filters use pkt_pos as a variable available to user-supplied
  expressions, but there seems to be no established motivation for using them.
- pkt_size was added for use in ffprobe, but that too is now handled
  without using this field. Additonally, the values of this field
  produced by libavcodec are flawed, as described in the previous
  ffprobe conversion commit.

In summary - these fields are ill-defined and insufficiently motivated,
so deprecate them.
2023-03-20 10:42:09 +01:00

136 lines
3.3 KiB
C

/*
* Original MPlayer filters by Richard Felker, Hampa Hug, Daniel Moreno,
* and Michael Niedermeyer.
*
* Copyright (c) 2014 James Darnley <james.darnley@gmail.com>
* Copyright (c) 2015 Arwa Arif <arwaarif1994@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef AVFILTER_EQ_H
#define AVFILTER_EQ_H
#include "avfilter.h"
#include "libavutil/eval.h"
static const char *const var_names[] = {
"n", // frame count
#if FF_API_FRAME_PKT
"pos", // frame position
#endif
"r", // frame rate
"t", // timestamp expressed in seconds
NULL
};
enum var_name {
VAR_N,
#if FF_API_FRAME_PKT
VAR_POS,
#endif
VAR_R,
VAR_T,
VAR_NB
};
typedef struct EQParameters {
void (*adjust)(struct EQParameters *eq, uint8_t *dst, int dst_stride,
const uint8_t *src, int src_stride, int w, int h);
uint8_t lut[256];
double brightness, contrast, gamma, gamma_weight;
int lut_clean;
} EQParameters;
typedef struct EQContext {
const AVClass *class;
EQParameters param[3];
char *contrast_expr;
AVExpr *contrast_pexpr;
double contrast;
char *brightness_expr;
AVExpr *brightness_pexpr;
double brightness;
char *saturation_expr;
AVExpr *saturation_pexpr;
double saturation;
char *gamma_expr;
AVExpr *gamma_pexpr;
double gamma;
char *gamma_weight_expr;
AVExpr *gamma_weight_pexpr;
double gamma_weight;
char *gamma_r_expr;
AVExpr *gamma_r_pexpr;
double gamma_r;
char *gamma_g_expr;
AVExpr *gamma_g_pexpr;
double gamma_g;
char *gamma_b_expr;
AVExpr *gamma_b_pexpr;
double gamma_b;
double var_values[VAR_NB];
void (*process)(struct EQParameters *par, uint8_t *dst, int dst_stride,
const uint8_t *src, int src_stride, int w, int h);
enum EvalMode { EVAL_MODE_INIT, EVAL_MODE_FRAME, EVAL_MODE_NB } eval_mode;
} EQContext;
static void process_c(EQParameters *param, uint8_t *dst, int dst_stride,
const uint8_t *src, int src_stride, int w, int h)
{
int contrast = (int) (param->contrast * 256 * 16);
int brightness = ((int) (100.0 * param->brightness + 100.0) * 511) / 200 - 128 - contrast / 32;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
int pel = ((src[y * src_stride + x] * contrast) >> 12) + brightness;
if (pel & ~255)
pel = (-pel) >> 31;
dst[y * dst_stride + x] = pel;
}
}
}
void ff_eq_init_x86(EQContext *eq);
static av_unused void ff_eq_init(EQContext *eq)
{
eq->process = process_c;
#if ARCH_X86
ff_eq_init_x86(eq);
#endif
}
#endif /* AVFILTER_EQ_H */