[FFmpeg-devel] [PATCH] avfilter/af_atempo: switch to rdft from lavu/tx

Pavel Koshevoy pkoshevoy at gmail.com
Sun Feb 6 19:15:37 EET 2022


On Sun, Feb 6, 2022 at 4:24 AM Paul B Mahol <onemda at gmail.com> wrote:

> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  configure               |   3 -
>  libavfilter/af_atempo.c | 126 ++++++++++++++++++++--------------------
>  2 files changed, 64 insertions(+), 65 deletions(-)
>
> diff --git a/configure b/configure
> index 5a8b52c77d..6ec25dd622 100755
> --- a/configure
> +++ b/configure
> @@ -3610,8 +3610,6 @@ amovie_filter_deps="avcodec avformat"
>  aresample_filter_deps="swresample"
>  asr_filter_deps="pocketsphinx"
>  ass_filter_deps="libass"
> -atempo_filter_deps="avcodec"
> -atempo_filter_select="rdft"
>  avgblur_opencl_filter_deps="opencl"
>  avgblur_vulkan_filter_deps="vulkan spirv_compiler"
>  azmq_filter_deps="libzmq"
> @@ -7387,7 +7385,6 @@ enabled zlib && add_cppflags -DZLIB_CONST
>  # conditional library dependencies, in any order
>  enabled amovie_filter       && prepend avfilter_deps "avformat avcodec"
>  enabled aresample_filter    && prepend avfilter_deps "swresample"
> -enabled atempo_filter       && prepend avfilter_deps "avcodec"
>  enabled bm3d_filter         && prepend avfilter_deps "avcodec"
>  enabled cover_rect_filter   && prepend avfilter_deps "avformat avcodec"
>  enabled ebur128_filter && enabled swresample && prepend avfilter_deps
> "swresample"
> diff --git a/libavfilter/af_atempo.c b/libavfilter/af_atempo.c
> index e9a6da7970..27f2f6daa0 100644
> --- a/libavfilter/af_atempo.c
> +++ b/libavfilter/af_atempo.c
> @@ -39,13 +39,13 @@
>   */
>
>  #include <float.h>
> -#include "libavcodec/avfft.h"
>  #include "libavutil/avassert.h"
>  #include "libavutil/avstring.h"
>  #include "libavutil/channel_layout.h"
>  #include "libavutil/eval.h"
>  #include "libavutil/opt.h"
>  #include "libavutil/samplefmt.h"
> +#include "libavutil/tx.h"
>  #include "avfilter.h"
>  #include "audio.h"
>  #include "internal.h"
> @@ -67,7 +67,8 @@ typedef struct AudioFragment {
>
>      // rDFT transform of the down-mixed mono fragment, used for
>      // fast waveform alignment via correlation in frequency domain:
> -    FFTSample *xdat;
> +    float *xdat_in;
> +    float *xdat;
>  } AudioFragment;
>
>
Is the old API being removed or deprecated?
Just wondering why this change is necessary.




>  /**
> @@ -140,9 +141,11 @@ typedef struct ATempoContext {
>      FilterState state;
>
>      // for fast correlation calculation in frequency domain:
> -    RDFTContext *real_to_complex;
> -    RDFTContext *complex_to_real;
> -    FFTSample *correlation;
> +    AVTXContext *real_to_complex;
> +    AVTXContext *complex_to_real;
> +    av_tx_fn r2c_fn, c2r_fn;
> +    float *correlation_in;
> +    float *correlation;
>
>      // for managing AVFilterPad.request_frame and AVFilterPad.filter_frame
>      AVFrame *dst_buffer;
> @@ -228,18 +231,18 @@ static void yae_release_buffers(ATempoContext
> *atempo)
>
>      av_freep(&atempo->frag[0].data);
>      av_freep(&atempo->frag[1].data);
> +    av_freep(&atempo->frag[0].xdat_in);
> +    av_freep(&atempo->frag[1].xdat_in);
>      av_freep(&atempo->frag[0].xdat);
>      av_freep(&atempo->frag[1].xdat);
>
>      av_freep(&atempo->buffer);
>      av_freep(&atempo->hann);
> +    av_freep(&atempo->correlation_in);
>      av_freep(&atempo->correlation);
>
> -    av_rdft_end(atempo->real_to_complex);
> -    atempo->real_to_complex = NULL;
> -
> -    av_rdft_end(atempo->complex_to_real);
> -    atempo->complex_to_real = NULL;
> +    av_tx_uninit(&atempo->real_to_complex);
> +    av_tx_uninit(&atempo->complex_to_real);
>  }
>
>  /* av_realloc is not aligned enough; fortunately, the data does not need
> to
> @@ -247,7 +250,7 @@ static void yae_release_buffers(ATempoContext *atempo)
>  #define RE_MALLOC_OR_FAIL(field, field_size)                    \
>      do {                                                        \
>          av_freep(&field);                                       \
> -        field = av_malloc(field_size);                          \
> +        field = av_calloc(field_size, 1);                       \
>          if (!field) {                                           \
>              yae_release_buffers(atempo);                        \
>              return AVERROR(ENOMEM);                             \
> @@ -265,6 +268,7 @@ static int yae_reset(ATempoContext *atempo,
>  {
>      const int sample_size = av_get_bytes_per_sample(format);
>      uint32_t nlevels  = 0;
> +    float scale = 1.f, iscale = 1.f;
>      uint32_t pot;
>      int i;
>
> @@ -288,29 +292,29 @@ static int yae_reset(ATempoContext *atempo,
>      // initialize audio fragment buffers:
>      RE_MALLOC_OR_FAIL(atempo->frag[0].data, atempo->window *
> atempo->stride);
>      RE_MALLOC_OR_FAIL(atempo->frag[1].data, atempo->window *
> atempo->stride);
> -    RE_MALLOC_OR_FAIL(atempo->frag[0].xdat, atempo->window *
> sizeof(FFTComplex));
> -    RE_MALLOC_OR_FAIL(atempo->frag[1].xdat, atempo->window *
> sizeof(FFTComplex));
> +    RE_MALLOC_OR_FAIL(atempo->frag[0].xdat_in, (atempo->window + 1) *
> sizeof(AVComplexFloat));
> +    RE_MALLOC_OR_FAIL(atempo->frag[1].xdat_in, (atempo->window + 1) *
> sizeof(AVComplexFloat));
> +    RE_MALLOC_OR_FAIL(atempo->frag[0].xdat, (atempo->window + 1) *
> sizeof(AVComplexFloat));
> +    RE_MALLOC_OR_FAIL(atempo->frag[1].xdat, (atempo->window + 1) *
> sizeof(AVComplexFloat));
>
>      // initialize rDFT contexts:
> -    av_rdft_end(atempo->real_to_complex);
> -    atempo->real_to_complex = NULL;
> -
> -    av_rdft_end(atempo->complex_to_real);
> -    atempo->complex_to_real = NULL;
> +    av_tx_uninit(&atempo->real_to_complex);
> +    av_tx_uninit(&atempo->complex_to_real);
>
> -    atempo->real_to_complex = av_rdft_init(nlevels + 1, DFT_R2C);
> +    av_tx_init(&atempo->real_to_complex, &atempo->r2c_fn,
> AV_TX_FLOAT_RDFT, 0, 1 << (nlevels + 1), &scale, 0);
>      if (!atempo->real_to_complex) {
>          yae_release_buffers(atempo);
>          return AVERROR(ENOMEM);
>      }
>
> -    atempo->complex_to_real = av_rdft_init(nlevels + 1, IDFT_C2R);
> +    av_tx_init(&atempo->complex_to_real, &atempo->c2r_fn,
> AV_TX_FLOAT_RDFT, 1, 1 << (nlevels + 1), &iscale, 0);
>      if (!atempo->complex_to_real) {
>          yae_release_buffers(atempo);
>          return AVERROR(ENOMEM);
>      }
>
> -    RE_MALLOC_OR_FAIL(atempo->correlation, atempo->window *
> sizeof(FFTComplex));
> +    RE_MALLOC_OR_FAIL(atempo->correlation_in, (atempo->window + 1) *
> sizeof(AVComplexFloat));
> +    RE_MALLOC_OR_FAIL(atempo->correlation, atempo->window *
> sizeof(AVComplexFloat));
>
>      atempo->ring = atempo->window * 3;
>      RE_MALLOC_OR_FAIL(atempo->buffer, atempo->ring * atempo->stride);
> @@ -348,7 +352,7 @@ static int yae_update(AVFilterContext *ctx)
>          const uint8_t *src_end = src +                                  \
>              frag->nsamples * atempo->channels * sizeof(scalar_type);    \
>                                                                          \
> -        FFTSample *xdat = frag->xdat;                                   \
> +        float *xdat = frag->xdat_in;                                    \
>          scalar_type tmp;                                                \
>                                                                          \
>          if (atempo->channels == 1) {                                    \
> @@ -356,27 +360,27 @@ static int yae_update(AVFilterContext *ctx)
>                  tmp = *(const scalar_type *)src;                        \
>                  src += sizeof(scalar_type);                             \
>                                                                          \
> -                *xdat = (FFTSample)tmp;                                 \
> +                *xdat = (float)tmp;                                     \
>              }                                                           \
>          } else {                                                        \
> -            FFTSample s, max, ti, si;                                   \
> +            float s, max, ti, si;                                       \
>              int i;                                                      \
>                                                                          \
>              for (; src < src_end; xdat++) {                             \
>                  tmp = *(const scalar_type *)src;                        \
>                  src += sizeof(scalar_type);                             \
>                                                                          \
> -                max = (FFTSample)tmp;                                   \
> -                s = FFMIN((FFTSample)scalar_max,                        \
> -                          (FFTSample)fabsf(max));                       \
> +                max = (float)tmp;                                       \
> +                s = FFMIN((float)scalar_max,                            \
> +                          (float)fabsf(max));                           \
>                                                                          \
>                  for (i = 1; i < atempo->channels; i++) {                \
>                      tmp = *(const scalar_type *)src;                    \
>                      src += sizeof(scalar_type);                         \
>                                                                          \
> -                    ti = (FFTSample)tmp;                                \
> -                    si = FFMIN((FFTSample)scalar_max,                   \
> -                               (FFTSample)fabsf(ti));                   \
> +                    ti = (float)tmp;                                    \
> +                    si = FFMIN((float)scalar_max,                       \
> +                               (float)fabsf(ti));                       \
>                                                                          \
>                      if (s < si) {                                       \
>                          s   = si;                                       \
> @@ -399,7 +403,7 @@ static void yae_downmix(ATempoContext *atempo,
> AudioFragment *frag)
>      const uint8_t *src = frag->data;
>
>      // init complex data buffer used for FFT and Correlation:
> -    memset(frag->xdat, 0, sizeof(FFTComplex) * atempo->window);
> +    memset(frag->xdat_in, 0, sizeof(AVComplexFloat) * atempo->window);
>
>      if (atempo->format == AV_SAMPLE_FMT_U8) {
>          yae_init_xdat(uint8_t, 127);
> @@ -598,32 +602,24 @@ static void yae_advance_to_next_frag(ATempoContext
> *atempo)
>   * Multiply two vectors of complex numbers (result of real_to_complex
> rDFT)
>   * and transform back via complex_to_real rDFT.
>   */
> -static void yae_xcorr_via_rdft(FFTSample *xcorr,
> -                               RDFTContext *complex_to_real,
> -                               const FFTComplex *xa,
> -                               const FFTComplex *xb,
> +static void yae_xcorr_via_rdft(float *xcorr_in,
> +                               float *xcorr,
> +                               AVTXContext *complex_to_real,
> +                               av_tx_fn c2r_fn,
> +                               const AVComplexFloat *xa,
> +                               const AVComplexFloat *xb,
>                                 const int window)
>  {
> -    FFTComplex *xc = (FFTComplex *)xcorr;
> +    AVComplexFloat *xc = (AVComplexFloat *)xcorr_in;
>      int i;
>
> -    // NOTE: first element requires special care -- Given Y = rDFT(X),
> -    // Im(Y[0]) and Im(Y[N/2]) are always zero, therefore av_rdft_calc
> -    // stores Re(Y[N/2]) in place of Im(Y[0]).
> -
> -    xc->re = xa->re * xb->re;
> -    xc->im = xa->im * xb->im;
> -    xa++;
> -    xb++;
> -    xc++;
> -
> -    for (i = 1; i < window; i++, xa++, xb++, xc++) {
> +    for (i = 0; i <= window; i++, xa++, xb++, xc++) {
>

This used to iterate over [1, window - 1] elements.
Now it iterates over [0, window] elements.
Is this correct?  That's 2 additional elements.



>          xc->re = (xa->re * xb->re + xa->im * xb->im);
>          xc->im = (xa->im * xb->re - xa->re * xb->im);
>      }
>
>      // apply inverse rDFT:
> -    av_rdft_calc(complex_to_real, xcorr);
> +    c2r_fn(complex_to_real, xcorr, xcorr_in, sizeof(float));
>  }
>
>  /**
> @@ -637,21 +633,25 @@ static int yae_align(AudioFragment *frag,
>                       const int window,
>                       const int delta_max,
>                       const int drift,
> -                     FFTSample *correlation,
> -                     RDFTContext *complex_to_real)
> +                     float *correlation_in,
> +                     float *correlation,
> +                     AVTXContext *complex_to_real,
> +                     av_tx_fn c2r_fn)
>  {
>      int       best_offset = -drift;
> -    FFTSample best_metric = -FLT_MAX;
> -    FFTSample *xcorr;
> +    float     best_metric = -FLT_MAX;
> +    float    *xcorr;
>
>      int i0;
>      int i1;
>      int i;
>
> -    yae_xcorr_via_rdft(correlation,
> +    yae_xcorr_via_rdft(correlation_in,
> +                       correlation,
>                         complex_to_real,
> -                       (const FFTComplex *)prev->xdat,
> -                       (const FFTComplex *)frag->xdat,
> +                       c2r_fn,
> +                       (const AVComplexFloat *)prev->xdat,
> +                       (const AVComplexFloat *)frag->xdat,
>                         window);
>
>      // identify search window boundaries:
> @@ -665,11 +665,11 @@ static int yae_align(AudioFragment *frag,
>      xcorr = correlation + i0;
>
>      for (i = i0; i < i1; i++, xcorr++) {
> -        FFTSample metric = *xcorr;
> +        float metric = *xcorr;
>
>          // normalize:
> -        FFTSample drifti = (FFTSample)(drift + i);
> -        metric *= drifti * (FFTSample)(i - i0) * (FFTSample)(i1 - i);
> +        float drifti = (float)(drift + i);
> +        metric *= drifti * (float)(i - i0) * (float)(i1 - i);
>
>          if (metric > best_metric) {
>              best_metric = metric;
> @@ -706,8 +706,10 @@ static int yae_adjust_position(ATempoContext *atempo)
>                                       atempo->window,
>                                       delta_max,
>                                       drift,
> +                                     atempo->correlation_in,
>                                       atempo->correlation,
> -                                     atempo->complex_to_real);
> +                                     atempo->complex_to_real,
> +                                     atempo->c2r_fn);
>
>      if (correction) {
>          // adjust fragment position:
> @@ -833,7 +835,7 @@ yae_apply(ATempoContext *atempo,
>              yae_downmix(atempo, yae_curr_frag(atempo));
>
>              // apply rDFT:
> -            av_rdft_calc(atempo->real_to_complex,
> yae_curr_frag(atempo)->xdat);
> +            atempo->r2c_fn(atempo->real_to_complex,
> yae_curr_frag(atempo)->xdat, yae_curr_frag(atempo)->xdat_in, sizeof(float));
>
>              // must load the second fragment before alignment can start:
>              if (!atempo->nfrag) {
> @@ -865,7 +867,7 @@ yae_apply(ATempoContext *atempo,
>              yae_downmix(atempo, yae_curr_frag(atempo));
>
>              // apply rDFT:
> -            av_rdft_calc(atempo->real_to_complex,
> yae_curr_frag(atempo)->xdat);
> +            atempo->r2c_fn(atempo->real_to_complex,
> yae_curr_frag(atempo)->xdat, yae_curr_frag(atempo)->xdat_in, sizeof(float));
>
>              atempo->state = YAE_OUTPUT_OVERLAP_ADD;
>          }
> @@ -929,7 +931,7 @@ static int yae_flush(ATempoContext *atempo,
>              yae_downmix(atempo, frag);
>
>              // apply rDFT:
> -            av_rdft_calc(atempo->real_to_complex, frag->xdat);
> +            atempo->r2c_fn(atempo->real_to_complex, frag->xdat,
> frag->xdat_in, sizeof(float));
>
>              // align current fragment to previous fragment:
>              if (yae_adjust_position(atempo)) {
> --
> 2.33.0
>
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