[FFmpeg-devel] [PATCH] avfilter: add sinc source filter

[Moritz Barsnick]

On Sat, Oct 13, 2018 at 23:14:59 +0200, Paul B Mahol wrote:

I see a few promotions from float to double arithmetic in here. Note
that initializations don't matter, the preprocessor handles assigning a
double to a float and downscales (casts) automatically. But
float_var = float_var * double_const
promotes. If that's undesired, a few constants need an 'f' qualifier.

Example:

> +    float term = 1, sum = 1, last_sum, x2 = x / 2;

The first two don't matter, but the latter turns into a CPU
calculation.

> +    float mult = scale / bessel_I_0(beta), mult1 = 1 / (.5 * m + rho);

-> 1.f / (.5f * m + rho)

> +    .description   = NULL_IF_CONFIG_SMALL("Generate a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject FIR coefficients."),

Apart from the length of the string, I don't understand "Generate a ...
coefficients". Is the "a" too much?

Does it generate coefficients, or does it use them for something?

Cheers,
Moritz