[vlc-devel] [RFC PATCH 3/7] audio_filter: add ebur128 "audio meter" plugin

Steve Lhomme robux4 at ycbcr.xyz
Mon Aug 17 08:48:33 CEST 2020


On 2020-08-14 15:18, Thomas Guillem wrote:
> ---
>   configure.ac                      |   5 +
>   modules/audio_filter/Makefile.am  |   9 +-
>   modules/audio_filter/libebur128.c | 290 ++++++++++++++++++++++++++++++
>   3 files changed, 303 insertions(+), 1 deletion(-)
>   create mode 100644 modules/audio_filter/libebur128.c
> 
> diff --git a/configure.ac b/configure.ac
> index 149c7c926b4..862546e49f3 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -3919,6 +3919,11 @@ dnl  soxr module
>   dnl
>   PKG_ENABLE_MODULES_VLC([SOXR], [], [soxr >= 0.1.2], [SoX Resampler library], [auto])
>   
> +dnl
> +dnl  libebur128 module
> +dnl
> +PKG_ENABLE_MODULES_VLC([EBUR128], [], [libebur128 >= 1.2.4], [EBU R 128 standard for loudness normalisation], [auto])
> +
>   dnl
>   dnl  OS/2 KAI plugin
>   dnl
> diff --git a/modules/audio_filter/Makefile.am b/modules/audio_filter/Makefile.am
> index 279be02040f..028b188bfe2 100644
> --- a/modules/audio_filter/Makefile.am
> +++ b/modules/audio_filter/Makefile.am
> @@ -125,14 +125,21 @@ libsoxr_plugin_la_CPPFLAGS = $(AM_CPPFLAGS) $(SOXR_CFLAGS)
>   libsoxr_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(audio_filterdir)'
>   libsoxr_plugin_la_LIBADD = $(SOXR_LIBS) $(LIBM)
>   
> +libebur128_plugin_la_SOURCES = audio_filter/libebur128.c
> +libebur128_plugin_la_CPPFLAGS = $(AM_CPPFLAGS) $(EBUR128_CFLAGS)
> +libebur128_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(audio_filterdir)'
> +libebur128_plugin_la_LIBADD = $(EBUR128_LIBS)
> +
>   audio_filter_LTLIBRARIES += \
>   	$(LTLIBsamplerate) \
>   	$(LTLIBsoxr) \
> +	$(LTLIBebur128) \
>   	libugly_resampler_plugin.la
>   EXTRA_LTLIBRARIES += \
>   	libbandlimited_resampler_plugin.la \
>   	libsamplerate_plugin.la \
> -	libsoxr_plugin.la
> +	libsoxr_plugin.la \
> +	libebur128_plugin.la
>   
>   libspeex_resampler_plugin_la_SOURCES = audio_filter/resampler/speex.c
>   libspeex_resampler_plugin_la_CFLAGS = $(AM_CFLAGS) $(SPEEXDSP_CFLAGS)
> diff --git a/modules/audio_filter/libebur128.c b/modules/audio_filter/libebur128.c
> new file mode 100644
> index 00000000000..bd5464dc6d1
> --- /dev/null
> +++ b/modules/audio_filter/libebur128.c
> @@ -0,0 +1,290 @@
> +/*****************************************************************************
> + * libebur128.c : libebur128 filter
> + *****************************************************************************
> + * Copyright © 2020 Videolabs
> + *
> + * This program 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.
> + *
> + * This program 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 this program; if not, write to the Free Software Foundation,
> + * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
> + *****************************************************************************/
> +
> +#ifdef HAVE_CONFIG_H
> +# include "config.h"
> +#endif
> +
> +#include <vlc_common.h>
> +#include <vlc_aout.h>
> +#include <vlc_filter.h>
> +#include <vlc_modules.h>
> +#include <vlc_plugin.h>
> +
> +#include <ebur128.h>
> +
> +#define UPDATE_INTERVAL VLC_TICK_FROM_MS(400)
> +
> +struct filter_sys
> +{
> +    ebur128_state *state;
> +    vlc_tick_t last_update;
> +    bool new_frames;
> +};
> +
> +static ebur128_state *
> +CreateEbuR128State(filter_t *filter)
> +{
> +    int mode = var_InheritBool(filter, "ebur128-fullmeter")
> +             ? EBUR128_MODE_TRUE_PEAK|EBUR128_MODE_LRA : EBUR128_MODE_M;
> +
> +    ebur128_state *state =
> +        ebur128_init(filter->fmt_in.audio.i_channels, filter->fmt_in.audio.i_rate, mode);
> +    if (state == NULL)
> +        return NULL;
> +
> +    /* TODO: improve */
> +    unsigned channels_set = 2;
> +    int error;
> +    if (filter->fmt_in.audio.i_physical_channels == AOUT_CHANS_5_1
> +     || filter->fmt_in.audio.i_physical_channels == AOUT_CHANS_7_1)
> +    {
> +        error = ebur128_set_channel(state, 2, EBUR128_LEFT_SURROUND);
> +        if (error != EBUR128_SUCCESS)
> +            goto error;
> +        ebur128_set_channel(state, 3, EBUR128_RIGHT_SURROUND);
> +        if (error != EBUR128_SUCCESS)
> +            goto error;
> +        ebur128_set_channel(state, 4, EBUR128_CENTER);
> +        if (error != EBUR128_SUCCESS)
> +            goto error;
> +
> +        channels_set += 3;
> +    }
> +
> +    for (unsigned i = channels_set; i < filter->fmt_in.audio.i_channels; ++i)
> +    {
> +        error = ebur128_set_channel(state, i, EBUR128_UNUSED);
> +        if (error != EBUR128_SUCCESS)
> +            goto error;
> +    }
> +
> +    return state;
> +error:
> +    ebur128_destroy(&state);
> +    return NULL;
> +}
> +
> +static int
> +SendLoudnessMeter(filter_t *filter)
> +{
> +    struct filter_sys *sys = filter->p_sys;
> +
> +    int error;
> +    struct vlc_audio_loudness_meter meter = { 0, 0, 0, 0, 0 };
> +
> +    error = ebur128_loudness_momentary(sys->state, &meter.loudness_momentary);
> +    if (error != EBUR128_SUCCESS)
> +        return error;
> +
> +    if ((sys->state->mode & EBUR128_MODE_S) == EBUR128_MODE_S)
> +    {
> +        error = ebur128_loudness_shortterm(sys->state, &meter.loudness_shortterm);
> +        if (error != EBUR128_SUCCESS)
> +            return error;
> +    }
> +    if ((sys->state->mode & EBUR128_MODE_I) == EBUR128_MODE_I)
> +    {
> +        error = ebur128_loudness_global(sys->state, &meter.loudness_integrated);
> +        if (error != EBUR128_SUCCESS)
> +            return error;
> +
> +    }
> +    if ((sys->state->mode & EBUR128_MODE_LRA) == EBUR128_MODE_LRA)
> +    {
> +        error = ebur128_loudness_range(sys->state, &meter.loudness_range);
> +        if (error != EBUR128_SUCCESS)
> +            return error;
> +    }
> +    if ((sys->state->mode & EBUR128_MODE_TRUE_PEAK) == EBUR128_MODE_TRUE_PEAK)
> +    {
> +        for (unsigned i = 0; i < filter->fmt_in.audio.i_channels; ++i)
> +        {
> +            double truepeak;
> +            error = ebur128_true_peak(sys->state, 0, &truepeak);
> +            if (error != EBUR128_SUCCESS)
> +                return error;
> +            if (truepeak > meter.truepeak)
> +                meter.truepeak = truepeak;
> +        }
> +    }
> +
> +    var_SetAddress(vlc_object_parent(VLC_OBJECT(filter)), "loudness-meter", &meter);

I'm not a big fan of this. I'd prefer timed data attached to the audio 
blocks (or in a separate ES). This would provide more or less accurate 
values with each audio block. It could be used in the vout to blend in 
the UI. Here if there's a delay between the decoder and the playback the 
display also has this delay.

> +
> +    return EBUR128_SUCCESS;
> +}
> +
> +static block_t *
> +Process(filter_t *filter, block_t *block)
> +{
> +    struct filter_sys *sys = filter->p_sys;
> +    int error;
> +    block_t *out = block;
> +
> +    if (unlikely(sys->state == NULL))
> +    {
> +        /* Can happen after a flush */
> +        sys->state = CreateEbuR128State(filter);
> +        if (sys->state == NULL)
> +            return out;
> +    }
> +
> +    switch (filter->fmt_in.i_codec)
> +    {
> +        case VLC_CODEC_U8:
> +        {
> +            /* Convert to S16N */
> +            block_t *block_s16 = block_Alloc(block->i_buffer * 2);
> +            if (unlikely(block_s16 == NULL))
> +                return out;
> +
> +            block_CopyProperties(block_s16, block);
> +            uint8_t *src = (uint8_t *)block->p_buffer;
> +            int16_t *dst = (int16_t *)block_s16->p_buffer;
> +            for (size_t i = block->i_buffer; i--;)
> +                *dst++ = ((*src++) << 8) - 0x8000;
> +
> +            block = block_s16;
> +        }
> +        /* Fallthrough */
> +        case VLC_CODEC_S16N:
> +            error = ebur128_add_frames_short(sys->state,
> +                                             (const short *)block->p_buffer,
> +                                             block->i_nb_samples);
> +            break;
> +        case VLC_CODEC_S32N:
> +            error = ebur128_add_frames_int(sys->state,
> +                                           (const int *) block->p_buffer,
> +                                           block->i_nb_samples);
> +            break;
> +        case VLC_CODEC_FL32:
> +            error = ebur128_add_frames_float(sys->state,
> +                                             (const float *) block->p_buffer,
> +                                             block->i_nb_samples);
> +            break;
> +        case VLC_CODEC_FL64:
> +            error = ebur128_add_frames_double(sys->state,
> +                                              (const double *) block->p_buffer,
> +                                              block->i_nb_samples);
> +            break;
> +        default: vlc_assert_unreachable();
> +    }
> +
> +    if (error != EBUR128_SUCCESS)
> +    {
> +        msg_Warn(filter, "ebur128_add_frames_*() failed: %d\n", error);
> +        return out;
> +    }
> +
> +    if (sys->last_update == VLC_TICK_INVALID)
> +        sys->last_update = out->i_pts;
> +
> +    if (out->i_pts + out->i_length - sys->last_update >= UPDATE_INTERVAL)
> +    {
> +        error = SendLoudnessMeter(filter);
> +        if (error == EBUR128_SUCCESS)
> +        {
> +            sys->last_update = out->i_pts + out->i_length;
> +            sys->new_frames = false;
> +        }
> +    }
> +    else
> +        sys->new_frames = true;
> +
> +    return out;
> +}
> +
> +static void
> +Flush(filter_t *filter)
> +{
> +    struct filter_sys *sys = filter->p_sys;
> +
> +    if (sys->state != NULL)
> +    {
> +        if (sys->new_frames)
> +        {
> +            SendLoudnessMeter(filter);
> +            sys->new_frames = false;
> +        }
> +        sys->last_update = VLC_TICK_INVALID;
> +
> +        ebur128_destroy(&sys->state);
> +    }
> +}
> +
> +static int Open(vlc_object_t *this)
> +{
> +    filter_t *filter = (filter_t *) this;
> +
> +    switch (filter->fmt_in.i_codec)
> +    {
> +        case VLC_CODEC_U8:
> +        case VLC_CODEC_S16N:
> +        case VLC_CODEC_S32N:
> +        case VLC_CODEC_FL32:
> +        case VLC_CODEC_FL64:
> +            break;
> +        default:
> +            return VLC_EGENERIC;
> +    }
> +
> +    if (var_Type(vlc_object_parent(this), "loudness-meter") != VLC_VAR_ADDRESS)
> +        return VLC_EGENERIC;
> +
> +    struct filter_sys *sys = malloc(sizeof(*sys));
> +    if (sys == NULL)
> +        return VLC_ENOMEM;
> +
> +    sys->last_update = VLC_TICK_INVALID;
> +    sys->new_frames = false;
> +    sys->state = CreateEbuR128State(filter);
> +    if (sys->state == NULL)
> +    {
> +        free(sys);
> +        return VLC_EGENERIC;
> +    }
> +
> +    filter->p_sys = sys;
> +    filter->fmt_out.audio = filter->fmt_in.audio;
> +    filter->pf_audio_filter = Process;
> +    filter->pf_flush = Flush;
> +    return VLC_SUCCESS;
> +}
> +
> +static void
> +Close(vlc_object_t *this)
> +{
> +    filter_t *filter = (filter_t*) this;
> +    struct filter_sys *sys = filter->p_sys;
> +
> +    if (sys->state != NULL)
> +        ebur128_destroy(&sys->state);
> +    free(filter->p_sys);
> +}
> +
> +vlc_module_begin()
> +    set_shortname("EBU R 128")
> +    set_description("EBU R128 standard for loudness normalisation")
> +    set_category(CAT_AUDIO)
> +    set_subcategory(SUBCAT_AUDIO_AFILTER)
> +    add_bool("ebur128-fullmeter", false, NULL, NULL, false)
> +    set_capability("audio meter", 0)
> +    set_callbacks(Open, Close)
> +vlc_module_end()
> -- 
> 2.28.0
> 
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