mpv/audio/filter/af_rubberband.c

/*
 * This file is part of mpv.
 *
 * mpv 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.
 *
 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <assert.h>

#include <rubberband/rubberband-c.h>

#include "common/common.h"
#include "af.h"

struct priv {
    RubberBandState rubber;
    double speed;
    struct mp_audio *pending;
    bool needs_reset;
    // Estimate how much librubberband has buffered internally.
    // I could not find a way to do this with the librubberband API.
    double rubber_delay;
    // command line options
    int opt_transients, opt_detector, opt_phase, opt_window,
        opt_smoothing, opt_formant, opt_pitch, opt_channels;
};

static void update_speed(struct af_instance *af, double new_speed)
{
    struct priv *p = af->priv;

    p->speed = new_speed;
    rubberband_set_time_ratio(p->rubber, 1.0 / p->speed);
}

static int control(struct af_instance *af, int cmd, void *arg)
{
    struct priv *p = af->priv;

    switch (cmd) {
    case AF_CONTROL_REINIT: {
        struct mp_audio *in = arg;
        struct mp_audio orig_in = *in;
        struct mp_audio *out = af->data;

        in->format = AF_FORMAT_FLOATP;
        mp_audio_copy_config(out, in);

        if (p->rubber)
            rubberband_delete(p->rubber);

        int opts = p->opt_transients | p->opt_detector | p->opt_phase |
                   p->opt_window | p->opt_smoothing | p->opt_formant |
                   p->opt_pitch | p-> opt_channels |
                   RubberBandOptionProcessRealTime;

        p->rubber = rubberband_new(in->rate, in->channels.num, opts, 1.0, 1.0);
        if (!p->rubber) {
            MP_FATAL(af, "librubberband initialization failed.\n");
            return AF_ERROR;
        }

        update_speed(af, p->speed);
        control(af, AF_CONTROL_RESET, NULL);

        return mp_audio_config_equals(in, &orig_in) ? AF_OK : AF_FALSE;
    }
    case AF_CONTROL_SET_PLAYBACK_SPEED: {
        update_speed(af, *(double *)arg);
        return AF_OK;
    }
    case AF_CONTROL_RESET:
        if (p->rubber)
            rubberband_reset(p->rubber);
        talloc_free(p->pending);
        p->pending = NULL;
        p->rubber_delay = 0;
        return AF_OK;
    }
    return AF_UNKNOWN;
}

static int filter_frame(struct af_instance *af, struct mp_audio *data)
{
    struct priv *p = af->priv;

    talloc_free(p->pending);
    p->pending = data;

    return 0;
}

static int filter_out(struct af_instance *af)
{
    struct priv *p = af->priv;

    while (rubberband_available(p->rubber) <= 0) {
        const float *dummy[MP_NUM_CHANNELS] = {0};
        const float **in_data = dummy;
        size_t in_samples = 0;
        if (p->pending) {
            if (!p->pending->samples)
                break;

            // recover from previous EOF
            if (p->needs_reset) {
                rubberband_reset(p->rubber);
                p->rubber_delay = 0;
            }
            p->needs_reset = false;

            size_t needs = rubberband_get_samples_required(p->rubber);
            in_data = (void *)&p->pending->planes;
            in_samples = MPMIN(p->pending->samples, needs);
        }

        if (p->needs_reset)
            break; // previous EOF
        p->needs_reset = !p->pending; // EOF

        rubberband_process(p->rubber, in_data, in_samples, p->needs_reset);
        p->rubber_delay += in_samples;

        if (!p->pending)
            break;
        mp_audio_skip_samples(p->pending, in_samples);
    }

    int out_samples = rubberband_available(p->rubber);
    if (out_samples > 0) {
        struct mp_audio *out =
            mp_audio_pool_get(af->out_pool, af->data, out_samples);
        if (!out)
            return -1;
        if (p->pending)
            mp_audio_copy_config(out, p->pending);

        float **out_data = (void *)&out->planes;
        out->samples = rubberband_retrieve(p->rubber, out_data, out->samples);
        p->rubber_delay -= out->samples * p->speed;

        af_add_output_frame(af, out);
    }

    int delay_samples = p->rubber_delay;
    if (p->pending)
        delay_samples += p->pending->samples;
    af->delay = delay_samples / (af->data->rate * p->speed);

    return 0;
}

static void uninit(struct af_instance *af)
{
    struct priv *p = af->priv;

    if (p->rubber)
        rubberband_delete(p->rubber);
    talloc_free(p->pending);
}

static int af_open(struct af_instance *af)
{
    af->control = control;
    af->filter_frame = filter_frame;
    af->filter_out = filter_out;
    af->uninit = uninit;
    return AF_OK;
}

#define OPT_BASE_STRUCT struct priv
const struct af_info af_info_rubberband = {
    .info = "Pitch conversion with librubberband",
    .name = "rubberband",
    .open = af_open,
    .priv_size = sizeof(struct priv),
    .priv_defaults = &(const struct priv) {
        .speed = 1.0,
        .opt_pitch = RubberBandOptionPitchHighConsistency,
        .opt_transients = RubberBandOptionTransientsMixed,
        .opt_formant = RubberBandOptionFormantPreserved,
    },
    .options = (const struct m_option[]) {
        OPT_CHOICE("transients", opt_transients, 0,
                   ({"crisp", RubberBandOptionTransientsCrisp},
                    {"mixed", RubberBandOptionTransientsMixed},
                    {"smooth", RubberBandOptionTransientsSmooth})),
        OPT_CHOICE("detector", opt_detector, 0,
                   ({"compound", RubberBandOptionDetectorCompound},
                    {"percussive", RubberBandOptionDetectorPercussive},
                    {"soft", RubberBandOptionDetectorSoft})),
        OPT_CHOICE("phase", opt_phase, 0,
                   ({"laminar", RubberBandOptionPhaseLaminar},
                    {"independent", RubberBandOptionPhaseIndependent})),
        OPT_CHOICE("window", opt_window, 0,
                   ({"standard", RubberBandOptionWindowStandard},
                    {"short", RubberBandOptionWindowShort},
                    {"long", RubberBandOptionWindowLong})),
        OPT_CHOICE("smoothing", opt_smoothing, 0,
                   ({"off", RubberBandOptionSmoothingOff},
                    {"on", RubberBandOptionSmoothingOn})),
        OPT_CHOICE("formant", opt_formant, 0,
                   ({"shifted", RubberBandOptionFormantShifted},
                    {"preserved", RubberBandOptionFormantPreserved})),
        OPT_CHOICE("pitch", opt_pitch, 0,
                   ({"quality", RubberBandOptionPitchHighQuality},
                    {"speed", RubberBandOptionPitchHighSpeed},
                    {"consistency", RubberBandOptionPitchHighConsistency})),
        OPT_CHOICE("channels", opt_channels, 0,
                   ({"apart", RubberBandOptionChannelsApart},
                    {"together", RubberBandOptionChannelsTogether})),
        {0}
    },
};