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avfilter/af_afftfilt: extend filter functionality

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This commit is contained in:
Paul B Mahol 2018-11-11 21:11:30 +01:00
parent 679ad31469
commit bdc66c50dd
2 changed files with 74 additions and 17 deletions
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16
doc/filters.texi
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@ -1082,7 +1082,7 @@ Set frequency domain imaginary expression for each separate channel
separated by '|'. If not set, @var{real} option is used.
Each expression in @var{real} and @var{imag} can contain the following
constants:
constants and functions:
@table @option
@item sr
@ -1102,6 +1102,18 @@ number of channels
@item pts
current frame pts
@item re
current real part of frequency bin
@item im
current imaginary part of frequency bin
@item real(b, ch)
Return the value of real part of frequency bin at location (@var{bin},@var{channel})
@item imag(b, ch)
Return the value of imaginary part of frequency bin at location (@var{bin},@var{channel})
@end table
@item win_size
@ -1139,7 +1151,7 @@ window function will be picked. Default is @code{0.75}.
@item
Leave almost only low frequencies in audio:
@example
afftfilt="1-clip((b/nb)*b,0,1)"
afftfilt="'real=re * (1-clip((b/nb)*b,0,1))':imag='im * (1-clip((b/nb)*b,0,1))'"
@end example
@end itemize

75
libavfilter/af_afftfilt.c
View File

@ -36,6 +36,7 @@ typedef struct AFFTFiltContext {
FFTContext *fft, *ifft;
FFTComplex **fft_data;
FFTComplex **fft_temp;
int nb_exprs;
int window_size;
AVExpr **real;
@ -51,15 +52,15 @@ typedef struct AFFTFiltContext {
float *window_func_lut;
} AFFTFiltContext;
static const char *const var_names[] = { "sr", "b", "nb", "ch", "chs", "pts", NULL };
enum { VAR_SAMPLE_RATE, VAR_BIN, VAR_NBBINS, VAR_CHANNEL, VAR_CHANNELS, VAR_PTS, VAR_VARS_NB };
static const char *const var_names[] = { "sr", "b", "nb", "ch", "chs", "pts", "re", "im", NULL };
enum { VAR_SAMPLE_RATE, VAR_BIN, VAR_NBBINS, VAR_CHANNEL, VAR_CHANNELS, VAR_PTS, VAR_REAL, VAR_IMAG, VAR_VARS_NB };
#define OFFSET(x) offsetof(AFFTFiltContext, x)
#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
static const AVOption afftfilt_options[] = {
{ "real", "set channels real expressions", OFFSET(real_str), AV_OPT_TYPE_STRING, {.str = "1" }, 0, 0, A },
{ "imag", "set channels imaginary expressions", OFFSET(img_str), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, A },
{ "real", "set channels real expressions", OFFSET(real_str), AV_OPT_TYPE_STRING, {.str = "re" }, 0, 0, A },
{ "imag", "set channels imaginary expressions", OFFSET(img_str), AV_OPT_TYPE_STRING, {.str = "im" }, 0, 0, A },
{ "win_size", "set window size", OFFSET(fft_bits), AV_OPT_TYPE_INT, {.i64=12}, 4, 17, A, "fft" },
{ "w16", 0, 0, AV_OPT_TYPE_CONST, {.i64=4}, 0, 0, A, "fft" },
{ "w32", 0, 0, AV_OPT_TYPE_CONST, {.i64=5}, 0, 0, A, "fft" },
@ -88,6 +89,34 @@ static const AVOption afftfilt_options[] = {
AVFILTER_DEFINE_CLASS(afftfilt);
static inline double getreal(void *priv, double x, double ch)
{
AFFTFiltContext *s = priv;
int ich, ix;
ich = av_clip(ch, 0, s->nb_exprs - 1);
ix = av_clip(x, 0, s->window_size / 2);
return s->fft_data[ich][ix].re;
}
static inline double getimag(void *priv, double x, double ch)
{
AFFTFiltContext *s = priv;
int ich, ix;
ich = av_clip(ch, 0, s->nb_exprs - 1);
ix = av_clip(x, 0, s->window_size / 2);
return s->fft_data[ich][ix].im;
}
static double realf(void *priv, double x, double ch) { return getreal(priv, x, ch); }
static double imagf(void *priv, double x, double ch) { return getimag(priv, x, ch); }
static const char *const func2_names[] = { "real", "imag", NULL };
double (*func2[])(void *, double, double) = { realf, imagf, NULL };
static int config_input(AVFilterLink *inlink)
{
AVFilterContext *ctx = inlink->dst;
@ -109,12 +138,22 @@ static int config_input(AVFilterLink *inlink)
if (!s->fft_data)
return AVERROR(ENOMEM);
s->fft_temp = av_calloc(inlink->channels, sizeof(*s->fft_temp));
if (!s->fft_temp)
return AVERROR(ENOMEM);
for (ch = 0; ch < inlink->channels; ch++) {
s->fft_data[ch] = av_calloc(s->window_size, sizeof(**s->fft_data));
if (!s->fft_data[ch])
return AVERROR(ENOMEM);
}
for (ch = 0; ch < inlink->channels; ch++) {
s->fft_temp[ch] = av_calloc(s->window_size, sizeof(**s->fft_temp));
if (!s->fft_temp[ch])
return AVERROR(ENOMEM);
}
s->real = av_calloc(inlink->channels, sizeof(*s->real));
if (!s->real)
return AVERROR(ENOMEM);
@ -131,7 +170,7 @@ static int config_input(AVFilterLink *inlink)
char *arg = av_strtok(ch == 0 ? args : NULL, "|", &saveptr);
ret = av_expr_parse(&s->real[ch], arg ? arg : last_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx);
NULL, NULL, func2_names, func2, 0, ctx);
if (ret < 0)
break;
if (arg)
@ -149,7 +188,7 @@ static int config_input(AVFilterLink *inlink)
char *arg = av_strtok(ch == 0 ? args : NULL, "|", &saveptr);
ret = av_expr_parse(&s->imag[ch], arg ? arg : last_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx);
NULL, NULL, func2_names, func2, 0, ctx);
if (ret < 0)
break;
if (arg)
@ -235,6 +274,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
for (ch = 0; ch < inlink->channels; ch++) {
FFTComplex *fft_data = s->fft_data[ch];
FFTComplex *fft_temp = s->fft_temp[ch];
float *buf = (float *)s->buffer->extended_data[ch];
int x;
@ -243,35 +283,37 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
av_fft_permute(s->fft, fft_data);
av_fft_calc(s->fft, fft_data);
for (n = 0; n < window_size / 2; n++) {
for (n = 0; n <= window_size / 2; n++) {
float fr, fi;
values[VAR_BIN] = n;
values[VAR_REAL] = fft_data[n].re;
values[VAR_IMAG] = fft_data[n].im;
fr = av_expr_eval(s->real[ch], values, s);
fi = av_expr_eval(s->imag[ch], values, s);
fft_data[n].re *= fr;
fft_data[n].im *= fi;
fft_temp[n].re = fr;
fft_temp[n].im = fi;
}
for (n = window_size / 2 + 1, x = window_size / 2 - 1; n < window_size; n++, x--) {
fft_data[n].re = fft_data[x].re;
fft_data[n].im = -fft_data[x].im;
fft_temp[n].re = fft_temp[x].re;
fft_temp[n].im = -fft_temp[x].im;
}
av_fft_permute(s->ifft, fft_data);
av_fft_calc(s->ifft, fft_data);
av_fft_permute(s->ifft, fft_temp);
av_fft_calc(s->ifft, fft_temp);
start = s->start;
end = s->end;
k = end;
for (i = 0, j = start; j < k && i < window_size; i++, j++) {
buf[j] += s->fft_data[ch][i].re * f;
buf[j] += s->fft_temp[ch][i].re * f;
}
for (; i < window_size; i++, j++) {
buf[j] = s->fft_data[ch][i].re * f;
buf[j] = s->fft_temp[ch][i].re * f;
}
start += s->hop_size;
@ -362,8 +404,11 @@ static av_cold void uninit(AVFilterContext *ctx)
for (i = 0; i < s->nb_exprs; i++) {
if (s->fft_data)
av_freep(&s->fft_data[i]);
if (s->fft_temp)
av_freep(&s->fft_temp[i]);
}
av_freep(&s->fft_data);
av_freep(&s->fft_temp);
for (i = 0; i < s->nb_exprs; i++) {
av_expr_free(s->real[i]);