Hello, I have written a very primitive code for porting FFT domain filter. It accepts only gray8 format images. The output should be a grayscale image, but the ouput image is coming out to be a black and white image. Also, I am getting confused when to do the vertical pass. After taking irdft of the horizontal pass or before it?
I have attached the patch.
From 455a261d7e2b3afba767aac2e73448aeee02d159 Mon Sep 17 00:00:00 2001 From: Arwa Arif <arwaarif1...@gmail.com> Date: Tue, 24 Feb 2015 12:17:30 +0530 Subject: [PATCH] Port FFT domain filter. --- libavfilter/Makefile | 1 + libavfilter/allfilters.c | 1 + libavfilter/vf_fftfilt.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 141 insertions(+) create mode 100644 libavfilter/vf_fftfilt.c diff --git a/libavfilter/Makefile b/libavfilter/Makefile index 289c63b..b184f07 100644 --- a/libavfilter/Makefile +++ b/libavfilter/Makefile @@ -120,6 +120,7 @@ OBJS-$(CONFIG_EDGEDETECT_FILTER) += vf_edgedetect.o OBJS-$(CONFIG_EQ_FILTER) += vf_eq.o OBJS-$(CONFIG_EXTRACTPLANES_FILTER) += vf_extractplanes.o OBJS-$(CONFIG_FADE_FILTER) += vf_fade.o +OBJS-$(CONFIG_FFTFILT_FILTER) += vf_fftfilt.o OBJS-$(CONFIG_FIELD_FILTER) += vf_field.o OBJS-$(CONFIG_FIELDMATCH_FILTER) += vf_fieldmatch.o OBJS-$(CONFIG_FIELDORDER_FILTER) += vf_fieldorder.o diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c index 55de154..043ac56 100644 --- a/libavfilter/allfilters.c +++ b/libavfilter/allfilters.c @@ -136,6 +136,7 @@ void avfilter_register_all(void) REGISTER_FILTER(EQ, eq, vf); REGISTER_FILTER(EXTRACTPLANES, extractplanes, vf); REGISTER_FILTER(FADE, fade, vf); + REGISTER_FILTER(FFTFILT, fftfilt, vf); REGISTER_FILTER(FIELD, field, vf); REGISTER_FILTER(FIELDMATCH, fieldmatch, vf); REGISTER_FILTER(FIELDORDER, fieldorder, vf); diff --git a/libavfilter/vf_fftfilt.c b/libavfilter/vf_fftfilt.c new file mode 100644 index 0000000..753bc8e --- /dev/null +++ b/libavfilter/vf_fftfilt.c @@ -0,0 +1,139 @@ +/* + * Copyright (c) 2015 Arwa Arif <arwaarif1...@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. + */ + +/** + * @file + * FFT domain filtering. + */ + +#include "libavfilter/internal.h" +#include "libavutil/common.h" +#include "libavutil/imgutils.h" +#include "libavutil/opt.h" +#include "libavutil/pixdesc.h" +#include "libavcodec/avfft.h" + +typedef struct { + const AVClass *class; + + RDFTContext *rdft; + int rdft_bits; + FFTSample *rdft_data; + +} FFTFILTContext; + +static int filter_frame(AVFilterLink *inlink, AVFrame *in) +{ + AVFilterContext *ctx = inlink->dst; + AVFilterLink *outlink = inlink->dst->outputs[0]; + FFTFILTContext *fftfilt = ctx->priv; + AVFrame *out; + int i, j, k, rdft_bits; + size_t rdft_len, w, h; + + w = inlink->w; + h = inlink->h; + + /* RDFT window size (precision) according to the requested output frame height */ + for (rdft_bits = 1; 1 << rdft_bits < 2 * w; rdft_bits++); + rdft_len = 1 << rdft_bits; + fftfilt->rdft_data = av_malloc_array(h, rdft_len * sizeof(FFTSample)); + memset(fftfilt->rdft_data, 0, rdft_len * h * sizeof(FFTSample)); + + out = ff_get_video_buffer(outlink, inlink->w, inlink->h); + if (!out) + return AVERROR(ENOMEM); + + av_frame_copy_props(out, in); + + /*Horizontal pass - RDFT*/ + fftfilt->rdft = av_rdft_init(rdft_bits, DFT_R2C); + k = 0; + for (i = 0; i < h; i++) + for (j = 0; j < w; j++) + { + fftfilt->rdft_data[k] = *(in->data[0] + in->linesize[0] * i + j); + k++; + } + + for (i = 0; i < h; i++) + av_rdft_calc(fftfilt->rdft, fftfilt->rdft_data + i * rdft_len); + + av_rdft_end(fftfilt->rdft); + + /*Horizontal pass - IRDFT*/ + fftfilt->rdft = av_rdft_init(rdft_bits, IDFT_C2R); + + for (i = 0; i < h; i++) + av_rdft_calc(fftfilt->rdft, fftfilt->rdft_data + i * rdft_len); + + k = 0; + for (i = 0; i < h; i++) + for (j = 0; j < w; j++) + { + *(out->data[0] + out->linesize[0] * i + j) = fftfilt->rdft_data[k]; + k++; + } + + av_rdft_end(fftfilt->rdft); + av_free(fftfilt->rdft_data); + + av_frame_free(&in); + + return ff_filter_frame(outlink, out); +} + +static int query_formats(AVFilterContext *ctx) +{ + static const enum AVPixelFormat pixel_fmts_fftfilt[] = { + AV_PIX_FMT_GRAY8, + AV_PIX_FMT_NONE + }; + + ff_set_common_formats(ctx, ff_make_format_list(pixel_fmts_fftfilt)); + + return 0; +} + +static const AVFilterPad fftfilt_inputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_VIDEO, + .filter_frame = filter_frame, + }, + { NULL } +}; + +static const AVFilterPad fftfilt_outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_VIDEO, + }, + { NULL } +}; + +AVFilter ff_vf_fftfilt = { + .name = "fftfilt", + .description = NULL_IF_CONFIG_SMALL("Adjust gain."), + .priv_size = sizeof(FFTFILTContext), + .inputs = fftfilt_inputs, + .outputs = fftfilt_outputs, + .query_formats = query_formats, +}; -- 1.7.9.5
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