[FFmpeg-devel] [PATCH lavfi: add showwaves filter
Nicolas George
nicolas.george at normalesup.org
Sun Jun 17 14:56:35 CEST 2012
(Maybe I already posted some of these remarks, I am not sure.)
Le decadi 30 prairial, an CCXX, Stefano Sabatini a écrit :
> From: Stefano Sabatini <stefasab at gmail.com>
> Date: Sun, 25 Dec 2011 17:37:53 +0100
> Subject: [PATCH] lavfi: add showwaves filter
>
> ---
> doc/filters.texi | 23 +++++
> libavfilter/Makefile | 2 +
> libavfilter/allfilters.c | 3 +
> libavfilter/avf_showwaves.c | 220 +++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 248 insertions(+), 0 deletions(-)
> create mode 100644 libavfilter/avf_showwaves.c
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index a354e97..cb61ed7 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -3815,3 +3815,26 @@ mainly useful as a template and to be employed in analysis / debugging
> tools.
>
> @c man end VIDEO SINKS
> +
> + at chapter Transmedia Filters
> + at c man begin TRANSMEDIA FILTERS
> +
> +Below is a description of the currently available transmedia filters.
> +
> + at section showwaves
> +
> +Convert input audio to a video output, representing the samples waves.
> +
> +The filter accepts the following named parameters:
> + at table @option
> + at item size, s
> +Specify the video size for the output. Default value is "320x240".
> + at end table
> +
> +The following example shows how to output the input file audio and the
> +corresponding video representation at the same time:
> + at example
> +amovie=a.mp3,asplit[out0],showwaves[out1]
> + at end example
> +
> + at c man end TRANSMEDIA FILTERS
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 72bb640..6de6ef4 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -193,6 +193,8 @@ OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/vf_yuvcsp.o
> OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/vf_yvu9.o
> OBJS-$(CONFIG_MP_FILTER) += libmpcodecs/pullup.o
>
> +# transmedia filters
> +OBJS-$(CONFIG_SHOWWAVES_FILTER) += avf_showwaves.o
>
> TESTPROGS = drawutils formats
>
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 35065d5..6d2d6cf 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -129,6 +129,9 @@ void avfilter_register_all(void)
> REGISTER_FILTER (BUFFERSINK, buffersink, vsink);
> REGISTER_FILTER (NULLSINK, nullsink, vsink);
>
> + /* transmedia filters */
> + REGISTER_FILTER (SHOWWAVES, showwaves, avf);
> +
> /* those filters are part of public or internal API => registered
> * unconditionally */
> {
> diff --git a/libavfilter/avf_showwaves.c b/libavfilter/avf_showwaves.c
> new file mode 100644
> index 0000000..bcb6545
> --- /dev/null
> +++ b/libavfilter/avf_showwaves.c
> @@ -0,0 +1,220 @@
> +/*
> + * Copyright (c) 2011 Stefano Sabatini
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 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
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser 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
> + * audio to video transmedia filter
> + */
> +
> +#include "libavutil/audioconvert.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/parseutils.h"
> +#include "avfilter.h"
> +#include "formats.h"
> +#include "audio.h"
> +#include "video.h"
> +
> +typedef struct {
> + const AVClass *class;
> + int w, h;
> + int buf_idx;
> + AVFilterBufferRef *outpicref;
> + int req_fullfilled;
> +} ShowWavesContext;
> +
> +#define OFFSET(x) offsetof(ShowWavesContext, x)
> +
> +static const AVOption showwaves_options[] = {
> + { "size", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "320x240"}, 0, 0 },
> + { "s", "set video size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str = "320x240"}, 0, 0 },
> + { NULL },
> +};
> +
> +static const AVClass showwaves_class = {
> + "showwaves",
> + av_default_item_name,
> + showwaves_options
> +};
> +
> +static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
> +{
> + ShowWavesContext *showwaves = ctx->priv;
> + int err;
> +
> + showwaves->class = &showwaves_class;
> + av_opt_set_defaults(showwaves);
> + showwaves->buf_idx = 0;
> +
> + if ((err = av_set_options_string(showwaves, args, "=", ":")) < 0) {
> + av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args);
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> + ShowWavesContext *showwaves = ctx->priv;
> +
> + avfilter_unref_bufferp(&showwaves->outpicref);
> +}
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> + AVFilterFormats *formats = NULL;
> + AVFilterChannelLayouts *layouts = NULL;
> + AVFilterLink *inlink = ctx->inputs[0];
> + AVFilterLink *outlink = ctx->outputs[0];
> + static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBL, -1 };
Using S16 would make the filter require less conversions and be bit-exact on
various architectures. You can use av_rescale to compute the height of the
bars.
> + static const enum PixelFormat pix_fmts[] = { PIX_FMT_GRAY8, -1 };
> +
> + /* set input audio formats */
> + formats = ff_make_format_list(sample_fmts);
> + if (!formats)
> + return AVERROR(ENOMEM);
> + ff_formats_ref(formats, &inlink->out_formats);
> +
> + layouts = ff_all_channel_layouts();
> + if (!layouts)
> + return AVERROR(ENOMEM);
> + ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts);
> +
> + formats = ff_all_samplerates();
> + if (!formats)
> + return AVERROR(ENOMEM);
> + ff_formats_ref(formats, &inlink->out_samplerates);
> +
> + /* set output video format */
> + formats = ff_make_format_list(pix_fmts);
> + if (!formats)
> + return AVERROR(ENOMEM);
> + ff_formats_ref(formats, &outlink->in_formats);
> +
> + return 0;
> +}
> +
> +static int config_output(AVFilterLink *outlink)
> +{
> + AVFilterContext *ctx = outlink->src;
> + ShowWavesContext *showwaves = ctx->priv;
> +
> + outlink->w = showwaves->w;
> + outlink->h = showwaves->h;
outlink->frame_rate = av_div_q((AVRational){ inlink->sample_rate, 1},
(AVRational){ showwaves->w, 1 });
... or something like that should allow it to work with -filter_complex too.
> +
> + av_log(ctx, AV_LOG_INFO, "s:%dx%d\n", showwaves->w, showwaves->h);
> + return 0;
> +}
> +
> +inline static void push_frame(AVFilterLink *outlink)
> +{
> + ShowWavesContext *showwaves = outlink->src->priv;
> +
> + ff_start_frame(outlink, showwaves->outpicref);
> + ff_draw_slice(outlink, 0, outlink->h, 1);
> + ff_end_frame(outlink);
> + showwaves->req_fullfilled = 1;
> + showwaves->outpicref = NULL;
> + showwaves->buf_idx = 0;
> +}
> +
> +static int request_frame(AVFilterLink *outlink)
> +{
> + ShowWavesContext *showwaves = outlink->src->priv;
> + AVFilterLink *inlink = outlink->src->inputs[0];
> + int ret;
> +
> + showwaves->req_fullfilled = 0;
> + do {
> + ret = avfilter_request_frame(inlink);
> + } while (!showwaves->req_fullfilled && ret >= 0);
> +
> + if (ret == AVERROR_EOF && showwaves->outpicref)
> + push_frame(outlink);
> + return ret;
> +}
> +
> +static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + AVFilterLink *outlink = ctx->outputs[0];
> + ShowWavesContext *showwaves = ctx->priv;
> + const int nb_samples = insamples->audio->nb_samples;
> + AVFilterBufferRef *outpicref = showwaves->outpicref;
> + int linesize = outpicref ? outpicref->linesize[0] : 0;
> + double *p = (double *)insamples->data[0];
> + int nb_channels = av_get_channel_layout_nb_channels(insamples->audio->channel_layout);
> + int i, j, h;
> +
> + /* draw data in the buffer */
> + for (i = 0; i < nb_samples; i++) {
> + if (showwaves->buf_idx == 0) {
> + showwaves->outpicref = outpicref =
> + ff_get_video_buffer(outlink, AV_PERM_WRITE|AV_PERM_ALIGN,
> + outlink->w, outlink->h);
> + outpicref->video->w = outlink->w;
> + outpicref->video->h = outlink->h;
> + outpicref->pts = insamples->pts;
> + outlink->out_buf = outpicref;
> + linesize = outpicref->linesize[0];
> + memset(outpicref->data[0], 0, showwaves->h*linesize);
> + }
> + for (j = 0; j < nb_channels; j++) {
> + h = showwaves->h/2 - (*p++ * showwaves->h/2);
> + if (h < outlink->h)
> + *(outpicref->data[0] + showwaves->buf_idx + h * linesize) = 255;
> + }
> + showwaves->buf_idx++;
> +
> + if (showwaves->buf_idx == showwaves->w)
> + push_frame(outlink);
With sample_rate = 44100 and w = 320, that makes 138 frames per second, it
is probably too much. What about incrementing buf_idx only once in n times,
n being an option defaulting to maybe 4.
And in that case, "= 255" may be replaced by "+= x", where x would be 255 /
(nb_channels * n)
> + }
> +
> + avfilter_unref_buffer(insamples);
> +}
> +
> +AVFilter avfilter_avf_showwaves = {
> + .name = "showwaves",
> + .description = NULL_IF_CONFIG_SMALL("Convert input audio to a video output."),
> + .init = init,
> + .uninit = uninit,
> + .query_formats = query_formats,
> + .priv_size = sizeof(ShowWavesContext),
> +
> + .inputs = (const AVFilterPad[]) {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_AUDIO,
> + .filter_samples = filter_samples,
> + .min_perms = AV_PERM_READ,
> + },
> + { .name = NULL }
> + },
> +
> + .outputs = (const AVFilterPad[]) {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .config_props = config_output,
> + .request_frame = request_frame,
> + },
> + { .name = NULL }
> + },
> +};
Regards,
--
Nicolas George
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