Parse and evaluate an expression.

Note, this is significantly slower than av_expr_eval().

Parameters

res a pointer to a double where is put the result value of the expression, or NAN in case of error

s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"

const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}

const_values a zero terminated array of values for the identifiers from const_names

func1_names NULL terminated array of zero terminated strings of funcs1 identifiers

funcs1 NULL terminated array of function pointers for functions which take 1 argument

func2_names NULL terminated array of zero terminated strings of funcs2 identifiers

funcs2 NULL terminated array of function pointers for functions which take 2 arguments

opaque a pointer which will be passed to all functions from funcs1 and funcs2

log_offset log level offset, can be used to silence error messages

log_ctx parent logging context

Returns

>= 0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 804 of file eval.c.

Referenced by activate(), av_parse_ratio(), calc_persp_luts(), config_input(), config_output_props(), config_props(), ff_print_eval_expr(), ff_print_formatted_eval_expr(), ff_scale_eval_dimensions(), filter_frame(), generate_kernel(), get_aspect_ratio(), main(), pad_opencl_config_output(), and set_string_number().

Parse an expression.

Parameters

expr a pointer where is put an AVExpr containing the parsed value in case of successful parsing, or NULL otherwise. The pointed to AVExpr must be freed with av_expr_free() by the user when it is not needed anymore.

s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"

const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}

func1_names NULL terminated array of zero terminated strings of funcs1 identifiers

funcs1 NULL terminated array of function pointers for functions which take 1 argument

func2_names NULL terminated array of zero terminated strings of funcs2 identifiers

funcs2 NULL terminated array of function pointers for functions which take 2 arguments

log_offset log level offset, can be used to silence error messages

log_ctx parent logging context

Returns

>= 0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 711 of file eval.c.

Referenced by addroi_init(), av_expr_parse_and_eval(), config_input(), config_output(), config_params(), config_props(), ff_rate_control_init(), generate_kernel(), geq_init(), init(), init_axis_color(), init_cqt(), init_volume(), initialize(), libplacebo_init(), modplug_read_header(), noise_init(), nppscale_parse_expr(), process_command(), process_forced_keyframes(), scale_parse_expr(), set_enable_expr(), set_expr(), and setts_init().

Evaluate a previously parsed expression.

Parameters

e the AVExpr to evaluate

const_values a zero terminated array of values for the identifiers from av_expr_parse() const_names

opaque a pointer which will be passed to all functions from funcs1 and funcs2

Returns

the value of the expression

Definition at line 793 of file eval.c.

Referenced by activate(), addroi_config_input(), av_expr_parse_and_eval(), config_input(), config_output(), config_props(), do_eval(), draw_text(), eval_expr(), eval_pts(), ff_inlink_evaluate_timeline_at_frame(), filter_channel(), filter_frame(), forced_kf_apply(), generate_kernel(), get_max_local_gain(), get_qscale(), get_target_gain(), init(), init_axis_color(), init_cqt(), init_volume(), modplug_read_packet(), noise(), nppscale_eval_dimensions(), output_single_frame(), parse_expr(), request_frame(), scale_eval_dimensions(), select_frame(), set_brightness(), set_contrast(), set_gamma(), set_saturation(), set_volume(), setts_filter(), slice_geq_filter(), update_alpha(), update_context(), and update_crops().

Track the presence of variables and their number of occurrences in a parsed expression.

Parameters

e the AVExpr to track variables in

counter a zero-initialized array where the count of each variable will be stored

size size of array

Returns

0 on success, a negative value indicates that no expression or array was passed or size was zero

Definition at line 783 of file eval.c.

Referenced by check_exprs(), nppscale_scale(), and scale_frame().

Track the presence of user provided functions and their number of occurrences in a parsed expression.

Parameters

e the AVExpr to track user provided functions in

counter a zero-initialized array where the count of each function will be stored if you passed 5 functions with 2 arguments to av_expr_parse() then for arg=2 this will use up to 5 entries.

size size of array

arg number of arguments the counted functions have

Returns

0 on success, a negative value indicates that no expression or array was passed or size was zero

Definition at line 788 of file eval.c.

Referenced by geq_init().

Free a parsed expression previously created with av_expr_parse().

Definition at line 359 of file eval.c.

Referenced by addroi_uninit(), av_expr_free(), av_expr_parse(), av_expr_parse_and_eval(), avfilter_free(), command(), config_input(), config_output(), config_props(), eval_expr(), ff_rate_control_uninit(), generate_kernel(), geq_uninit(), init(), init_axis_color(), init_cqt(), init_volume(), libplacebo_uninit(), noise_close(), nppscale_parse_expr(), nppscale_uninit(), ost_free(), overlay_cuda_uninit(), parse_channel_expressions(), parse_expr(), parse_factor(), parse_primary(), parse_subexpr(), parse_term(), process_command(), scale_parse_expr(), set_enable_expr(), set_expr(), setts_close(), and uninit().

Parse the string in numstr and return its value as a double.

If the string is empty, contains only whitespaces, or does not contain an initial substring that has the expected syntax for a floating-point number, no conversion is performed. In this case, returns a value of zero and the value returned in tail is the value of numstr.

Parameters

numstr a string representing a number, may contain one of the International System number postfixes, for example 'K', 'M', 'G'. If 'i' is appended after the postfix, powers of 2 are used instead of powers of 10. The 'B' postfix multiplies the value by 8, and can be appended after another postfix or used alone. This allows using for example 'KB', 'MiB', 'G' and 'B' as postfix.

tail if non-NULL puts here the pointer to the char next after the last parsed character

Definition at line 108 of file eval.c.

Referenced by ff_parse_sample_rate(), parse_number(), parse_points_str(), parse_primary(), parse_string(), parse_weights(), set_param(), and var_read_float().