[FFmpeg-devel] [PATCH] lavfi/volume: add dynamic expression evaluation
Nicolas George
george at nsup.org
Mon Dec 23 19:48:25 CET 2013
Le tridi 3 nivôse, an CCXXII, Stefano Sabatini a écrit :
> Updated with a solution similar to that of overlay. I don't plan to
> implement the av_expr_is_const() thing, and will probably push this
> variant unless there are objections.
>
> Comments are welcome.
> --
> FFmpeg = Free & Funny Magnificient Proud Elected Geisha
> >From 9afa55b01eb84e6615fff877dc718d192305abf3 Mon Sep 17 00:00:00 2001
> From: Stefano Sabatini <stefasab at gmail.com>
> Date: Sat, 23 Feb 2013 00:17:17 +0100
> Subject: [PATCH] lavfi/volume: support volume expression and per-frame
> expression evaluation
>
> The eval mode allows to evaluate the expression per-frame or just at
> init.
>
> In particular, address ticket #3234.
>
> TODO: bump micro
> ---
> doc/filters.texi | 55 ++++++++++++++++++-
> libavfilter/af_volume.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++--
> libavfilter/af_volume.h | 27 +++++++++
> 3 files changed, 217 insertions(+), 7 deletions(-)
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 8bcfd82..d29bedc 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -1796,7 +1796,7 @@ The filter accepts the following options:
> @table @option
>
> @item volume
> -Expresses how the audio volume will be increased or decreased.
> +Set audio volume expression.
>
> Output values are clipped to the maximum value.
>
> @@ -1805,7 +1805,7 @@ The output audio volume is given by the relation:
> @var{output_volume} = @var{volume} * @var{input_volume}
> @end example
>
> -Default value for @var{volume} is 1.0.
> +Default value for @var{volume} is "1.0".
>
> @item precision
> Set the mathematical precision.
> @@ -1821,8 +1821,53 @@ precision of the volume scaling.
> @item double
> 64-bit floating-point; limits input sample format to DBL.
> @end table
> +
> + at item eval
> +Set when the volume expression is evaluated.
> +
> +It accepts the following values:
> + at table @samp
> + at item init
> +only evaluate expression once during the filter initialization
> +
> + at item frame
> +evaluate expression for each incoming frame
> + at end table
> +
> +Default value is @samp{init}.
> + at end table
> +
> +The volume expression can contain the following parameters.
> +
> + at table @option
> + at item n
> +frame number (starting at zero)
> + at item nb_channels
> +number of channels
> + at item nb_consumed_samples
> +number of samples consumed by the filter
> + at item nb_samples
> +number of samples in the current frame
> + at item pos
> +original frame position in the file
> + at item pts
> +frame PTS
> + at item sample_rate
> +sample rate
> + at item startpts
> +PTS at start of stream
> + at item startt
> +time at start of stream
> + at item t
> +frame time
> + at item tb
> +timestamp timebase
> @end table
>
> +Note that when @option{eval} is set to @samp{init} only the
> + at var{sample_rate} and @var{tb} variables are available, all other
> +variables will evaluate to NAN.
> +
> @subsection Examples
>
> @itemize
> @@ -1845,6 +1890,12 @@ Increase input audio power by 6 decibels using fixed-point precision:
> @example
> volume=volume=6dB:precision=fixed
> @end example
> +
> + at item
> +Fade volume after time 10 with an annihilation period of 5 seconds:
> + at example
> +volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
> + at end example
> @end itemize
>
> @section volumedetect
> diff --git a/libavfilter/af_volume.c b/libavfilter/af_volume.c
> index 21fe9a1..9bfd840 100644
> --- a/libavfilter/af_volume.c
> +++ b/libavfilter/af_volume.c
> @@ -29,6 +29,7 @@
> #include "libavutil/eval.h"
> #include "libavutil/float_dsp.h"
> #include "libavutil/opt.h"
> +#include "libavutil/time.h"
> #include "audio.h"
> #include "avfilter.h"
> #include "formats.h"
> @@ -39,24 +40,42 @@ static const char *precision_str[] = {
> "fixed", "float", "double"
> };
>
> +static const char *const var_names[] = {
> + "n", ///< frame number (starting at zero)
> + "nb_channels", ///< number of channels
> + "nb_consumed_samples", ///< number of samples consumed by the filter
> + "nb_samples", ///< number of samples in the current frame
> + "pos", ///< position in the file of the frame
> + "pts", ///< frame presentation timestamp
> + "sample_rate", ///< sample rate
> + "startpts", ///< PTS at start of stream
> + "startt", ///< time at start of stream
> + "t", ///< time in the file of the frame
> + "tb", ///< timebase
> + NULL
> +};
> +
> #define OFFSET(x) offsetof(VolumeContext, x)
> #define A AV_OPT_FLAG_AUDIO_PARAM
> #define F AV_OPT_FLAG_FILTERING_PARAM
>
> static const AVOption volume_options[] = {
> - { "volume", "set volume adjustment",
> - OFFSET(volume), AV_OPT_TYPE_DOUBLE, { .dbl = 1.0 }, 0, 0x7fffff, A|F },
> + { "volume", "set volume adjustment expression",
> + OFFSET(volume_expr), AV_OPT_TYPE_STRING, { .str = "1.0" }, .flags = A|F },
> { "precision", "select mathematical precision",
> OFFSET(precision), AV_OPT_TYPE_INT, { .i64 = PRECISION_FLOAT }, PRECISION_FIXED, PRECISION_DOUBLE, A|F, "precision" },
> { "fixed", "select 8-bit fixed-point", 0, AV_OPT_TYPE_CONST, { .i64 = PRECISION_FIXED }, INT_MIN, INT_MAX, A|F, "precision" },
> { "float", "select 32-bit floating-point", 0, AV_OPT_TYPE_CONST, { .i64 = PRECISION_FLOAT }, INT_MIN, INT_MAX, A|F, "precision" },
> { "double", "select 64-bit floating-point", 0, AV_OPT_TYPE_CONST, { .i64 = PRECISION_DOUBLE }, INT_MIN, INT_MAX, A|F, "precision" },
> + { "eval", "specify when to evaluate expressions", OFFSET(eval_mode), AV_OPT_TYPE_INT, {.i64 = EVAL_MODE_INIT}, 0, EVAL_MODE_NB-1, .flags = A|F, "eval" },
> + { "init", "eval expressions once during initialization", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_INIT}, .flags = A|F, .unit = "eval" },
> + { "frame", "eval expressions per-frame", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_FRAME}, .flags = A|F, .unit = "eval" },
> { NULL }
> };
>
> AVFILTER_DEFINE_CLASS(volume);
>
> -static av_cold int init(AVFilterContext *ctx)
> +static void set_volume(AVFilterContext *ctx)
> {
> VolumeContext *vol = ctx->priv;
>
> @@ -70,10 +89,41 @@ static av_cold int init(AVFilterContext *ctx)
> vol->volume, 20.0*log(vol->volume)/M_LN10,
> precision_str[vol->precision]);
> }
> +}
> +
> +static int set_expr(AVExpr **pexpr, const char *expr, void *log_ctx)
> +{
> + int ret;
> + AVExpr *old = NULL;
> +
> + if (*pexpr)
> + old = *pexpr;
> + ret = av_expr_parse(pexpr, expr, var_names,
> + NULL, NULL, NULL, NULL, 0, log_ctx);
> + if (ret < 0) {
> + av_log(log_ctx, AV_LOG_ERROR,
> + "Error when evaluating the volume expression '%s'\n", expr);
> + *pexpr = old;
> + return ret;
> + }
>
> + av_expr_free(old);
> return 0;
> }
>
> +static av_cold int init(AVFilterContext *ctx)
> +{
> + VolumeContext *vol = ctx->priv;
> + return set_expr(&vol->volume_pexpr, vol->volume_expr, ctx);
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> + VolumeContext *vol = ctx->priv;
> + av_expr_free(vol->volume_pexpr);
> + av_opt_free(vol);
> +}
> +
> static int query_formats(AVFilterContext *ctx)
> {
> VolumeContext *vol = ctx->priv;
> @@ -204,25 +254,102 @@ static int config_output(AVFilterLink *outlink)
> AVFilterContext *ctx = outlink->src;
> VolumeContext *vol = ctx->priv;
> AVFilterLink *inlink = ctx->inputs[0];
> + int ret;
>
> vol->sample_fmt = inlink->format;
> vol->channels = inlink->channels;
> vol->planes = av_sample_fmt_is_planar(inlink->format) ? vol->channels : 1;
>
> + vol->var_values[VAR_N] =
> + vol->var_values[VAR_NB_CONSUMED_SAMPLES] =
> + vol->var_values[VAR_NB_SAMPLES] =
> + vol->var_values[VAR_POS] =
> + vol->var_values[VAR_PTS] =
> + vol->var_values[VAR_STARTPTS] =
> + vol->var_values[VAR_STARTT] =
> + vol->var_values[VAR_T] = NAN;
> +
> + vol->var_values[VAR_NB_CHANNELS] = inlink->channels;
> + vol->var_values[VAR_TB] = av_q2d(inlink->time_base);
> + vol->var_values[VAR_SAMPLE_RATE] = inlink->sample_rate;
> +
> + av_log(inlink->src, AV_LOG_VERBOSE, "TB:%f SAMPLE_RATE:%f\n",
> + vol->var_values[VAR_TB], vol->var_values[VAR_SAMPLE_RATE]);
> +
> volume_init(vol);
>
> + if (vol->eval_mode == EVAL_MODE_INIT) {
> + if ((ret = av_expr_parse(&vol->volume_pexpr, vol->volume_expr,
> + var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
> + av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n",
> + vol->volume_expr);
> + return ret;
> + }
It looks like duplicated code with set_expr().
> +
> + vol->volume = av_expr_eval(vol->volume_pexpr, vol->var_values, NULL);
> + if (isnan(vol->volume)) {
> + av_log(ctx, AV_LOG_ERROR, "Invalid value NaN for volume\n");
> + return AVERROR(EINVAL);
> + }
> +
> + set_volume(ctx);
This bit could probably be factored out, that would make the patch with
command processing slightly shorter.
> + }
> +
> return 0;
> }
>
> +#define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
> +#define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
> +#define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts)*av_q2d(tb))
> +
> static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
> {
> + AVFilterContext *ctx = inlink->dst;
> VolumeContext *vol = inlink->dst->priv;
> AVFilterLink *outlink = inlink->dst->outputs[0];
> int nb_samples = buf->nb_samples;
> AVFrame *out_buf;
> + int64_t pos;
> +
> + if (vol->eval_mode == EVAL_MODE_FRAME) {
> + if (isnan(vol->var_values[VAR_STARTPTS])) {
> + vol->var_values[VAR_STARTPTS] = TS2D(buf->pts);
> + vol->var_values[VAR_STARTT ] = TS2T(buf->pts, inlink->time_base);
> + }
> + vol->var_values[VAR_PTS] = TS2D(buf->pts);
> + vol->var_values[VAR_T ] = TS2T(buf->pts, inlink->time_base);
> + vol->var_values[VAR_N ] = inlink->frame_count;
> +
> + pos = av_frame_get_pkt_pos(buf);
> + vol->var_values[VAR_POS] = pos == -1 ? NAN : pos;
> +
> + vol->volume = av_expr_eval(vol->volume_pexpr, vol->var_values, NULL);
> + if (isnan(vol->volume)) {
> + av_log(ctx, AV_LOG_WARNING, "Invalid value NaN for volume, setting to 0\n");
> + vol->volume = 0;
> + }
>
> - if (vol->volume == 1.0 || vol->volume_i == 256)
> - return ff_filter_frame(outlink, buf);
> + set_volume(ctx);
> + if (vol->volume == 1.0 || vol->volume_i == 256) {
> + out_buf = buf;
> + goto end;
> + }
> + }
> +
> + switch (av_get_packed_sample_fmt(vol->sample_fmt)) {
> + case AV_SAMPLE_FMT_U8:
> + if (vol->volume_i < 0x1000000)
> + vol->scale_samples = scale_samples_u8_small;
> + else
> + vol->scale_samples = scale_samples_u8;
> + break;
> + case AV_SAMPLE_FMT_S16:
> + if (vol->volume_i < 0x10000)
> + vol->scale_samples = scale_samples_s16_small;
> + else
> + vol->scale_samples = scale_samples_s16;
> + break;
> + }
>
> /* do volume scaling in-place if input buffer is writable */
> if (av_frame_is_writable(buf)) {
> @@ -266,6 +393,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
> if (buf != out_buf)
> av_frame_free(&buf);
>
> +end:
> + if (vol->eval_mode == EVAL_MODE_FRAME)
> + vol->var_values[VAR_NB_CONSUMED_SAMPLES] += buf->nb_samples;
> +
> return ff_filter_frame(outlink, out_buf);
> }
>
> @@ -294,6 +425,7 @@ AVFilter ff_af_volume = {
> .priv_size = sizeof(VolumeContext),
> .priv_class = &volume_class,
> .init = init,
> + .uninit = uninit,
> .inputs = avfilter_af_volume_inputs,
> .outputs = avfilter_af_volume_outputs,
> .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
> diff --git a/libavfilter/af_volume.h b/libavfilter/af_volume.h
> index bd7932e..70b313f 100644
> --- a/libavfilter/af_volume.h
> +++ b/libavfilter/af_volume.h
> @@ -25,6 +25,7 @@
> #define AVFILTER_AF_VOLUME_H
>
> #include "libavutil/common.h"
> +#include "libavutil/eval.h"
> #include "libavutil/float_dsp.h"
> #include "libavutil/opt.h"
> #include "libavutil/samplefmt.h"
> @@ -35,10 +36,36 @@ enum PrecisionType {
> PRECISION_DOUBLE,
> };
>
> +enum EvalMode {
> + EVAL_MODE_INIT,
> + EVAL_MODE_FRAME,
> + EVAL_MODE_NB
> +};
> +
> +enum VolumeVarName {
> + VAR_N,
> + VAR_NB_CHANNELS,
> + VAR_NB_CONSUMED_SAMPLES,
> + VAR_NB_SAMPLES,
> + VAR_POS,
> + VAR_PTS,
> + VAR_SAMPLE_RATE,
> + VAR_STARTPTS,
> + VAR_STARTT,
> + VAR_T,
> + VAR_TB,
> + VAR_VARS_NB
> +};
> +
> typedef struct VolumeContext {
> const AVClass *class;
> AVFloatDSPContext fdsp;
> enum PrecisionType precision;
> + enum EvalMode eval_mode;
> + const char *volume_expr;
> + AVExpr *volume_pexpr;
> + double var_values[VAR_VARS_NB];
> +
> double volume;
> int volume_i;
> int channels;
Regards,
--
Nicolas George
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