A couple notes:

This is not ready to be merged into master. I have tested it with valgrind
and found leaks and invalid reads: http://paste.ubuntu.com/6929929/
I want to troubleshoot those before this gets merged.

Still, I think I addressed all the feedback so far, so any other feedback
is welcome.


On Fri, Feb 14, 2014 at 2:56 AM, Andrew Kelley <[email protected]> wrote:

> This patch adds the `compand` audio filter from ffmpeg master branch
> (currently at 7f0f47b3df) adapted to work with libav.
>
> The following changes are made:
>
>  * use float instead of double
>  * use strtok_r instead of av_strtok
>  * remove asserts
>  * use AVFrame instead of manually allocating memory
> ---
>  Changelog                |   1 +
>  doc/filters.texi         |  74 +++++++
>  libavfilter/Makefile     |   1 +
>  libavfilter/af_compand.c | 548
> +++++++++++++++++++++++++++++++++++++++++++++++
>  libavfilter/allfilters.c |   1 +
>  libavfilter/version.h    |   2 +-
>  6 files changed, 626 insertions(+), 1 deletion(-)
>  create mode 100644 libavfilter/af_compand.c
>
> diff --git a/Changelog b/Changelog
> index bed6c31..74b7f1a 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -58,6 +58,7 @@ version 10:
>  - Mirillis FIC video decoder
>  - Support DNx444
>  - libx265 encoder
> +- compand audio filter
>
>
>  version 9:
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 8c83b4e..8863384 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -467,6 +467,80 @@ To fix a 5.1 WAV improperly encoded in AAC's native
> channel order
>  avconv -i in.wav -filter 'channelmap=1|2|0|5|3|4:channel_layout=5.1'
> out.wav
>  @end example
>
> +@section compand
> +Compress or expand audio dynamic range.
> +
> +A description of the accepted options follows.
> +
> +@table @option
> +
> +@item attacks
> +@item decays
> +Set list of times in seconds for each channel over which the
> instantaneous level
> +of the input signal is averaged to determine its volume. @var{attacks}
> refers to
> +increase of volume and @var{decays} refers to decrease of volume. For most
> +situations, the attack time (response to the audio getting louder) should
> be
> +shorter than the decay time because the human ear is more sensitive to
> sudden
> +loud audio than sudden soft audio. Typical value for attack is 0.3
> seconds and
> +for decay 0.8 seconds.
> +
> +@item points
> +Set list of points for transfer function, specified in dB relative to
> maximum
> +possible signal amplitude. Each key points list need to be defined using
> the
> +following syntax: @code{x0/y0 x1/y1 x2/y2 ....}
> +
> +The input values must be in strictly increasing order but the transfer
> function
> +does not have to be monotonically rising. The point @code{0/0} is assumed
> but
> +may be overridden (by @code{0/out-dBn}). Typical values for the transfer
> +function are @code{-70/-70 -60/-20}.
> +
> +@item soft-knee
> +Set amount for which the points at where adjacent line segments on the
> transfer
> +function meet will be rounded. Defaults is 0.01.
> +
> +@item gain
> +Set additional gain in dB to be applied at all points on the transfer
> function
> +and allows easy adjustment of the overall gain. Default is 0.
> +
> +@item volume
> +Set initial volume in dB to be assumed for each channel when filtering
> starts.
> +This permits the user to supply a nominal level initially, so that, for
> +example, a very large gain is not applied to initial signal levels before
> the
> +companding has begun to operate. A typical value for audio which is
> initially
> +quiet is -90 dB. Default is 0.
> +
> +@item delay
> +Set delay in seconds. Default is 0. The input audio is analysed
> immediately,
> +but audio is delayed before being fed to the volume adjuster. Specifying a
> +delay approximately equal to the attack/decay times allows the filter to
> +effectively operate in predictive rather than reactive mode.
> +
> +@end table
> +
> +@subsection Examples
> +
> +@itemize
> +@item
> +Make music with both quiet and loud passages suitable for listening in a
> noisy
> +environment:
> +@example
> +compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2
> +@end example
> +
> +@item
> +Noise-gate for when the noise is at a lower level than the signal:
> +@example
> +compand=.1 .1:.2 .2:-900/-900 -50.1/-900 -50/-50:.01:0:-90:.1
> +@end example
> +
> +@item
> +Here is another noise-gate, this time for when the noise is at a higher
> level
> +than the signal (making it, in some ways, similar to squelch):
> +@example
> +compand=.1 .1:.1 .1:-45.1/-45.1 -45/-900 0/-900:.01:45:-90:.1
> +@end example
> +@end itemize
> +
>  @section join
>  Join multiple input streams into one multi-channel stream.
>
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 92c1561..2badb3e 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -37,6 +37,7 @@ OBJS-$(CONFIG_CHANNELSPLIT_FILTER)           +=
> af_channelsplit.o
>  OBJS-$(CONFIG_JOIN_FILTER)                   += af_join.o
>  OBJS-$(CONFIG_RESAMPLE_FILTER)               += af_resample.o
>  OBJS-$(CONFIG_VOLUME_FILTER)                 += af_volume.o
> +OBJS-$(CONFIG_COMPAND_FILTER)                += af_compand.o
>
>  OBJS-$(CONFIG_ANULLSRC_FILTER)               += asrc_anullsrc.o
>
> diff --git a/libavfilter/af_compand.c b/libavfilter/af_compand.c
> new file mode 100644
> index 0000000..d46dfa4
> --- /dev/null
> +++ b/libavfilter/af_compand.c
> @@ -0,0 +1,548 @@
> +/*
> + * Copyright (c) 1999 Chris Bagwell
> + * Copyright (c) 1999 Nick Bailey
> + * Copyright (c) 2007 Rob Sykes <[email protected]>
> + * Copyright (c) 2013 Paul B Mahol
> + * Copyright (c) 2014 Andrew Kelley
> + *
> + * This file is part of libav.
> + *
> + * Libav 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.
> + *
> + * Libav 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 Libav; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + *
> + */
> +
> +/**
> + * @file
> + * audio compand filter
> + */
> +
> +#include <string.h>
> +
> +#include "libavutil/channel_layout.h"
> +#include "libavutil/common.h"
> +#include "libavutil/mathematics.h"
> +#include "libavutil/mem.h"
> +#include "libavutil/opt.h"
> +#include "audio.h"
> +#include "avfilter.h"
> +#include "formats.h"
> +#include "internal.h"
> +
> +typedef struct ChanParam {
> +    float attack;
> +    float decay;
> +    float volume;
> +} ChanParam;
> +
> +typedef struct CompandSegment {
> +    float x, y;
> +    float a, b;
> +} CompandSegment;
> +
> +typedef struct CompandContext {
> +    const AVClass *class;
> +    int nb_channels;
> +    char *attacks, *decays, *points;
> +    CompandSegment *segments;
> +    ChanParam *channels;
> +    float in_min_lin;
> +    float out_min_lin;
> +    float curve_dB;
> +    float gain_dB;
> +    float initial_volume;
> +    float delay;
> +    AVFrame *delay_frame;
> +    int delay_samples;
> +    int delay_count;
> +    int delay_index;
> +    int64_t pts;
> +
> +    int (*compand)(AVFilterContext *ctx, AVFrame *frame);
> +} CompandContext;
> +
> +#define OFFSET(x) offsetof(CompandContext, x)
> +#define A AV_OPT_FLAG_AUDIO_PARAM
> +
> +static const AVOption compand_options[] = {
> +    { "attacks", "set time over which increase of volume is determined",
> OFFSET(attacks), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, A },
> +    { "decays", "set time over which decrease of volume is determined",
> OFFSET(decays), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, A },
> +    { "points", "set points of transfer function", OFFSET(points),
> AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, A },
> +    { "soft-knee", "set soft-knee", OFFSET(curve_dB), AV_OPT_TYPE_FLOAT,
> {.dbl=0.01}, 0.01, 900, A },
> +    { "gain", "set output gain", OFFSET(gain_dB), AV_OPT_TYPE_FLOAT,
> {.dbl=0}, -900, 900, A },
> +    { "volume", "set initial volume", OFFSET(initial_volume),
> AV_OPT_TYPE_FLOAT, {.dbl=0}, -900, 0, A },
> +    { "delay", "set delay for samples before sending them to volume
> adjuster", OFFSET(delay), AV_OPT_TYPE_FLOAT, {.dbl=0}, 0, 20, A },
> +    { NULL }
> +};
> +
> +static const AVClass compand_class = {
> +    .class_name = "compand filter",
> +    .item_name  = av_default_item_name,
> +    .option     = compand_options,
> +    .version    = LIBAVUTIL_VERSION_INT,
> +};
> +
> +static av_cold int init(AVFilterContext *ctx)
> +{
> +    CompandContext *s = ctx->priv;
> +
> +    if (!s->attacks || !s->decays || !s->points) {
> +        av_log(ctx, AV_LOG_ERROR, "Missing attacks and/or decays and/or
> points.\n");
> +        return AVERROR(EINVAL);
> +    }
> +
> +    return 0;
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> +    CompandContext *s = ctx->priv;
> +
> +    av_freep(&s->channels);
> +    av_freep(&s->segments);
> +    av_frame_free(&s->delay_frame);
> +}
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> +    AVFilterChannelLayouts *layouts;
> +    AVFilterFormats *formats;
> +    static const enum AVSampleFormat sample_fmts[] = {
> +        AV_SAMPLE_FMT_FLTP,
> +        AV_SAMPLE_FMT_NONE
> +    };
> +
> +    layouts = ff_all_channel_layouts();
> +    if (!layouts)
> +        return AVERROR(ENOMEM);
> +    ff_set_common_channel_layouts(ctx, layouts);
> +
> +    formats = ff_make_format_list(sample_fmts);
> +    if (!formats)
> +        return AVERROR(ENOMEM);
> +    ff_set_common_formats(ctx, formats);
> +
> +    formats = ff_all_samplerates();
> +    if (!formats)
> +        return AVERROR(ENOMEM);
> +    ff_set_common_samplerates(ctx, formats);
> +
> +    return 0;
> +}
> +
> +static void count_items(char *item_str, int *nb_items)
> +{
> +    char *p;
> +
> +    *nb_items = 1;
> +    for (p = item_str; *p; p++) {
> +        if (*p == ' ')
> +            (*nb_items)++;
> +    }
> +
> +}
> +
> +static void update_volume(ChanParam *cp, float in)
> +{
> +    float delta = in - cp->volume;
> +
> +    if (delta > 0.0)
> +        cp->volume += delta * cp->attack;
> +    else
> +        cp->volume += delta * cp->decay;
> +}
> +
> +static float get_volume(CompandContext *s, float in_lin)
> +{
> +    CompandSegment *cs;
> +    float in_log, out_log;
> +    int i;
> +
> +    if (in_lin < s->in_min_lin)
> +        return s->out_min_lin;
> +
> +    in_log = log(in_lin);
> +
> +    for (i = 1;; i++)
> +        if (in_log <= s->segments[i + 1].x)
> +            break;
> +
> +    cs = &s->segments[i];
> +    in_log -= cs->x;
> +    out_log = cs->y + in_log * (cs->a * in_log + cs->b);
> +
> +    return exp(out_log);
> +}
> +
> +static int compand_nodelay(AVFilterContext *ctx, AVFrame *frame)
> +{
> +    CompandContext *s = ctx->priv;
> +    AVFilterLink *inlink = ctx->inputs[0];
> +    const int channels = s->nb_channels;
> +    const int nb_samples = frame->nb_samples;
> +    AVFrame *out_frame;
> +    int chan, i;
> +
> +    if (av_frame_is_writable(frame)) {
> +        out_frame = frame;
> +    } else {
> +        out_frame = ff_get_audio_buffer(inlink, nb_samples);
> +        if (!out_frame)
> +            return AVERROR(ENOMEM);
> +        av_frame_copy_props(out_frame, frame);
> +    }
> +
> +    for (chan = 0; chan < channels; chan++) {
> +        const float *src = (float *)frame->extended_data[chan];
> +        float *dst = (float *)out_frame->extended_data[chan];
> +        ChanParam *cp = &s->channels[chan];
> +
> +        for (i = 0; i < nb_samples; i++) {
> +            update_volume(cp, fabs(src[i]));
> +
> +            dst[i] = av_clipf(src[i] * get_volume(s, cp->volume), -1, 1);
> +        }
> +    }
> +
> +    if (frame != out_frame)
> +        av_frame_free(&frame);
> +
> +    return ff_filter_frame(ctx->outputs[0], out_frame);
> +}
> +
> +#define MOD(a, b) (((a) >= (b)) ? (a) - (b) : (a))
> +
> +static int compand_delay(AVFilterContext *ctx, AVFrame *frame)
> +{
> +    CompandContext *s = ctx->priv;
> +    AVFilterLink *inlink = ctx->inputs[0];
> +    const int channels = s->nb_channels;
> +    const int nb_samples = frame->nb_samples;
> +    int chan, i, av_uninit(dindex), oindex, av_uninit(count);
> +    AVFrame *out_frame = NULL;
> +
> +    for (chan = 0; chan < channels; chan++) {
> +        AVFrame *delay_frame = s->delay_frame;
> +        const float *src = (float *)frame->extended_data[chan];
> +        float *dbuf = (float *)delay_frame->extended_data[chan];
> +        ChanParam *cp = &s->channels[chan];
> +        float *dst;
> +
> +        count  = s->delay_count;
> +        dindex = s->delay_index;
> +        for (i = 0, oindex = 0; i < nb_samples; i++) {
> +            const float in = src[i];
> +            update_volume(cp, fabs(in));
> +
> +            if (count >= s->delay_samples) {
> +                if (!out_frame) {
> +                    out_frame = ff_get_audio_buffer(inlink, nb_samples -
> i);
> +                    if (!out_frame)
> +                        return AVERROR(ENOMEM);
> +                    av_frame_copy_props(out_frame, frame);
> +                    out_frame->pts = s->pts;
> +                    s->pts += av_rescale_q(nb_samples - i,
> (AVRational){1, inlink->sample_rate}, inlink->time_base);
> +                }
> +
> +                dst = (float *)out_frame->extended_data[chan];
> +                dst[oindex++] = av_clipf(dbuf[dindex] * get_volume(s,
> cp->volume), -1, 1);
> +            } else {
> +                count++;
> +            }
> +
> +            dbuf[dindex] = in;
> +            dindex = MOD(dindex + 1, s->delay_samples);
> +        }
> +    }
> +
> +    s->delay_count = count;
> +    s->delay_index = dindex;
> +
> +    av_frame_free(&frame);
> +    return out_frame ? ff_filter_frame(ctx->outputs[0], out_frame) : 0;
> +}
> +
> +static int compand_drain(AVFilterLink *outlink)
> +{
> +    AVFilterContext *ctx = outlink->src;
> +    CompandContext *s = ctx->priv;
> +    const int channels = s->nb_channels;
> +    int chan, i, dindex;
> +    AVFrame *frame = NULL;
> +
> +    frame = ff_get_audio_buffer(outlink, FFMIN(2048, s->delay_count));
> +    if (!frame)
> +        return AVERROR(ENOMEM);
> +    frame->pts = s->pts;
> +    s->pts += av_rescale_q(frame->nb_samples, (AVRational){1,
> outlink->sample_rate}, outlink->time_base);
> +
> +    for (chan = 0; chan < channels; chan++) {
> +        AVFrame *delay_frame = s->delay_frame;
> +        float *dbuf = (float *)delay_frame->extended_data[chan];
> +        float *dst = (float *)frame->extended_data[chan];
> +        ChanParam *cp = &s->channels[chan];
> +
> +        dindex = s->delay_index;
> +        for (i = 0; i < frame->nb_samples; i++) {
> +            dst[i] = av_clipf(dbuf[dindex] * get_volume(s, cp->volume),
> -1, 1);
> +            dindex = MOD(dindex + 1, s->delay_samples);
> +        }
> +    }
> +    s->delay_count -= frame->nb_samples;
> +    s->delay_index = dindex;
> +
> +    return ff_filter_frame(outlink, frame);
> +}
> +
> +static int config_output(AVFilterLink *outlink)
> +{
> +    AVFilterContext *ctx = outlink->src;
> +    CompandContext *s = ctx->priv;
> +
> +    const int channels =
> av_get_channel_layout_nb_channels(outlink->channel_layout);
> +    const int sample_rate = outlink->sample_rate;
> +    float radius = s->curve_dB * M_LN10 / 20;
> +    int nb_attacks, nb_decays, nb_points;
> +    char *p, *saveptr = NULL;
> +    int new_nb_items, num;
> +    int i;
> +    int err;
> +
> +
> +    count_items(s->attacks, &nb_attacks);
> +    count_items(s->decays, &nb_decays);
> +    count_items(s->points, &nb_points);
> +
> +    if (channels <= 0) {
> +        av_log(ctx, AV_LOG_ERROR, "Invalid number of channels: %d\n",
> channels);
> +        return AVERROR(EINVAL);
> +    }
> +
> +    if ((nb_attacks > channels) || (nb_decays > channels)) {
> +        av_log(ctx, AV_LOG_ERROR, "Number of attacks/decays bigger than
> number of channels.\n");
> +        return AVERROR(EINVAL);
> +    }
> +
> +    uninit(ctx);
> +
> +    s->nb_channels = channels;
> +    s->channels = av_mallocz_array(channels, sizeof(*s->channels));
> +    s->segments = av_mallocz_array((nb_points + 4) * 2,
> sizeof(*s->segments));
> +
> +    if (!s->channels || !s->segments)
> +        return AVERROR(ENOMEM);
> +
> +    p = s->attacks;
> +    for (i = 0, new_nb_items = 0; i < nb_attacks; i++) {
> +        char *tstr = strtok_r(p, " ", &saveptr);
> +        p = NULL;
> +        new_nb_items += sscanf(tstr, "%f", &s->channels[i].attack) == 1;
> +        if (s->channels[i].attack < 0)
> +            return AVERROR(EINVAL);
> +    }
> +    nb_attacks = new_nb_items;
> +
> +    p = s->decays;
> +    for (i = 0, new_nb_items = 0; i < nb_decays; i++) {
> +        char *tstr = strtok_r(p, " ", &saveptr);
> +        p = NULL;
> +        new_nb_items += sscanf(tstr, "%f", &s->channels[i].decay) == 1;
> +        if (s->channels[i].decay < 0)
> +            return AVERROR(EINVAL);
> +    }
> +    nb_decays = new_nb_items;
> +
> +    if (nb_attacks != nb_decays) {
> +        av_log(ctx, AV_LOG_ERROR, "Number of attacks %d differs from
> number of decays %d.\n", nb_attacks, nb_decays);
> +        return AVERROR(EINVAL);
> +    }
> +
> +#define S(x) s->segments[2 * ((x) + 1)]
> +    p = s->points;
> +    for (i = 0, new_nb_items = 0; i < nb_points; i++) {
> +        char *tstr = strtok_r(p, " ", &saveptr);
> +        p = NULL;
> +        if (sscanf(tstr, "%f/%f", &S(i).x, &S(i).y) != 2) {
> +            av_log(ctx, AV_LOG_ERROR, "Invalid and/or missing
> input/output value.\n");
> +            return AVERROR(EINVAL);
> +        }
> +        if (i && S(i - 1).x > S(i).x) {
> +            av_log(ctx, AV_LOG_ERROR, "Transfer function input values
> must be increasing.\n");
> +            return AVERROR(EINVAL);
> +        }
> +        S(i).y -= S(i).x;
> +        av_log(ctx, AV_LOG_DEBUG, "%d: x=%f y=%f\n", i, S(i).x, S(i).y);
> +        new_nb_items++;
> +    }
> +    num = new_nb_items;
> +
> +    /* Add 0,0 if necessary */
> +    if (num == 0 || S(num - 1).x)
> +        num++;
> +
> +#undef S
> +#define S(x) s->segments[2 * (x)]
> +    /* Add a tail off segment at the start */
> +    S(0).x = S(1).x - 2 * s->curve_dB;
> +    S(0).y = S(1).y;
> +    num++;
> +
> +    /* Join adjacent colinear segments */
> +    for (i = 2; i < num; i++) {
> +        float g1 = (S(i - 1).y - S(i - 2).y) * (S(i - 0).x - S(i - 1).x);
> +        float g2 = (S(i - 0).y - S(i - 1).y) * (S(i - 1).x - S(i - 2).x);
> +        int j;
> +
> +        if (fabs(g1 - g2))
> +            continue;
> +        num--;
> +        for (j = --i; j < num; j++)
> +            S(j) = S(j + 1);
> +    }
> +
> +    for (i = 0; !i || s->segments[i - 2].x; i += 2) {
> +        s->segments[i].y += s->gain_dB;
> +        s->segments[i].x *= M_LN10 / 20;
> +        s->segments[i].y *= M_LN10 / 20;
> +    }
> +
> +#define L(x) s->segments[i - (x)]
> +    for (i = 4; s->segments[i - 2].x; i += 2) {
> +        float x, y, cx, cy, in1, in2, out1, out2, theta, len, r;
> +
> +        L(4).a = 0;
> +        L(4).b = (L(2).y - L(4).y) / (L(2).x - L(4).x);
> +
> +        L(2).a = 0;
> +        L(2).b = (L(0).y - L(2).y) / (L(0).x - L(2).x);
> +
> +        theta = atan2(L(2).y - L(4).y, L(2).x - L(4).x);
> +        len = sqrt(pow(L(2).x - L(4).x, 2.) + pow(L(2).y - L(4).y, 2.));
> +        r = FFMIN(radius, len);
> +        L(3).x = L(2).x - r * cos(theta);
> +        L(3).y = L(2).y - r * sin(theta);
> +
> +        theta = atan2(L(0).y - L(2).y, L(0).x - L(2).x);
> +        len = sqrt(pow(L(0).x - L(2).x, 2.) + pow(L(0).y - L(2).y, 2.));
> +        r = FFMIN(radius, len / 2);
> +        x = L(2).x + r * cos(theta);
> +        y = L(2).y + r * sin(theta);
> +
> +        cx = (L(3).x + L(2).x + x) / 3;
> +        cy = (L(3).y + L(2).y + y) / 3;
> +
> +        L(2).x = x;
> +        L(2).y = y;
> +
> +        in1 = cx - L(3).x;
> +        out1 = cy - L(3).y;
> +        in2 = L(2).x - L(3).x;
> +        out2 = L(2).y - L(3).y;
> +        L(3).a = (out2 / in2 - out1 / in1) / (in2-in1);
> +        L(3).b = out1 / in1 - L(3).a * in1;
> +    }
> +    L(3).x = 0;
> +    L(3).y = L(2).y;
> +
> +    s->in_min_lin  = exp(s->segments[1].x);
> +    s->out_min_lin = exp(s->segments[1].y);
> +
> +    for (i = 0; i < channels; i++) {
> +        ChanParam *cp = &s->channels[i];
> +
> +        if (cp->attack > 1.0 / sample_rate)
> +            cp->attack = 1.0 - exp(-1.0 / (sample_rate * cp->attack));
> +        else
> +            cp->attack = 1.0;
> +        if (cp->decay > 1.0 / sample_rate)
> +            cp->decay = 1.0 - exp(-1.0 / (sample_rate * cp->decay));
> +        else
> +            cp->decay = 1.0;
> +        cp->volume = pow(10.0, s->initial_volume / 20);
> +    }
> +
> +    s->delay_samples = s->delay * sample_rate;
> +    if (s->delay_samples <= 0) {
> +        s->compand = compand_nodelay;
> +        return 0;
> +    }
> +
> +    s->delay_frame = av_frame_alloc();
> +    if (!s->delay_frame)
> +        return AVERROR(ENOMEM);
> +
> +    s->delay_frame->format = outlink->format;
> +    s->delay_frame->nb_samples = s->delay_samples;
> +    s->delay_frame->channel_layout = outlink->channel_layout;
> +
> +    err = av_frame_get_buffer(s->delay_frame, 32);
> +    if (err)
> +        return err;
> +
> +    s->compand = compand_delay;
> +    return 0;
> +}
> +
> +static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
> +{
> +    AVFilterContext *ctx = inlink->dst;
> +    CompandContext *s = ctx->priv;
> +
> +    return s->compand(ctx, frame);
> +}
> +
> +static int request_frame(AVFilterLink *outlink)
> +{
> +    AVFilterContext *ctx = outlink->src;
> +    CompandContext *s = ctx->priv;
> +    int ret;
> +
> +    ret = ff_request_frame(ctx->inputs[0]);
> +
> +    if (ret == AVERROR_EOF && s->delay_count)
> +        ret = compand_drain(outlink);
> +
> +    return ret;
> +}
> +
> +static const AVFilterPad compand_inputs[] = {
> +    {
> +        .name         = "default",
> +        .type         = AVMEDIA_TYPE_AUDIO,
> +        .filter_frame = filter_frame,
> +    },
> +    { NULL }
> +};
> +
> +static const AVFilterPad compand_outputs[] = {
> +    {
> +        .name          = "default",
> +        .request_frame = request_frame,
> +        .config_props  = config_output,
> +        .type          = AVMEDIA_TYPE_AUDIO,
> +    },
> +    { NULL }
> +};
> +
> +
> +AVFilter ff_af_compand = {
> +    .name           = "compand",
> +    .description    = NULL_IF_CONFIG_SMALL("Compress or expand audio
> dynamic range."),
> +    .query_formats  = query_formats,
> +    .priv_size      = sizeof(CompandContext),
> +    .priv_class     = &compand_class,
> +    .init           = init,
> +    .inputs         = compand_inputs,
> +    .outputs        = compand_outputs,
> +};
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 9702a0a..e47a22e 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -54,6 +54,7 @@ void avfilter_register_all(void)
>      REGISTER_FILTER(ATRIM,          atrim,          af);
>      REGISTER_FILTER(CHANNELMAP,     channelmap,     af);
>      REGISTER_FILTER(CHANNELSPLIT,   channelsplit,   af);
> +    REGISTER_FILTER(COMPAND,        compand,        af);
>      REGISTER_FILTER(JOIN,           join,           af);
>      REGISTER_FILTER(RESAMPLE,       resample,       af);
>      REGISTER_FILTER(VOLUME,         volume,         af);
> diff --git a/libavfilter/version.h b/libavfilter/version.h
> index 1684aa5..f09b501 100644
> --- a/libavfilter/version.h
> +++ b/libavfilter/version.h
> @@ -30,7 +30,7 @@
>  #include "libavutil/version.h"
>
>  #define LIBAVFILTER_VERSION_MAJOR  4
> -#define LIBAVFILTER_VERSION_MINOR  1
> +#define LIBAVFILTER_VERSION_MINOR  2
>  #define LIBAVFILTER_VERSION_MICRO  0
>
>  #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR,
> \
> --
> 1.8.3.2
>
>
_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel

Reply via email to