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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.
This commit is contained in:
Stefano Sabatini 2013-02-23 00:17:17 +01:00
parent 239a0543a6
commit 7619a87cc8
4 changed files with 208 additions and 21 deletions
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57
doc/filters.texi
View File

@ -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 +1821,55 @@ precision of the volume scaling.
@item double
64-bit floating-point; limits input sample format to DBL.
@end table
@item eval
Set when the volume expression is evaluated.
It accepts the following values:
@table @samp
@item once
only evaluate expression once during the filter initialization
@item frame
evaluate expression for each incoming frame
@end table
Default value is @samp{once}.
@end table
The volume expression can contain the following parameters.
@table @option
@item n
frame number (starting at zero)
@item nb_channels
number of channels
@item nb_consumed_samples
number of samples consumed by the filter
@item nb_samples
number of samples in the current frame
@item pos
original frame position in the file
@item pts
frame PTS
@item sample_rate
sample rate
@item startpts
PTS at start of stream
@item startt
time at start of stream
@item t
frame time
@item tb
timestamp timebase
@item volume
last set volume value
@end table
Note that when @option{eval} is set to @samp{once} only the
@var{sample_rate} and @var{tb} variables are available, all other
variables will evaluate to NAN.
@subsection Examples
@itemize
@ -1845,6 +1892,12 @@ Increase input audio power by 6 decibels using fixed-point precision:
@example
volume=volume=6dB:precision=fixed
@end example
@item
Fade volume after time 10 with an annihilation period of 5 seconds:
@example
volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame
@end example
@end itemize
@section volumedetect

142
libavfilter/af_volume.c
View File

@ -39,39 +39,73 @@ 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
"volume", ///< last set value
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_ONCE}, 0, EVAL_MODE_NB-1, .flags = A|F, "eval" },
{ "once", "eval volume expression once", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_ONCE}, .flags = A|F, .unit = "eval" },
{ "frame", "eval volume expression per-frame", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_FRAME}, .flags = A|F, .unit = "eval" },
{ NULL }
};
AVFILTER_DEFINE_CLASS(volume);
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);
}
if (vol->precision == PRECISION_FIXED) {
vol->volume_i = (int)(vol->volume * 256 + 0.5);
vol->volume = vol->volume_i / 256.0;
av_log(ctx, AV_LOG_VERBOSE, "volume:(%d/256)(%f)(%1.2fdB) precision:fixed\n",
vol->volume_i, vol->volume, 20.0*log(vol->volume)/M_LN10);
} else {
av_log(ctx, AV_LOG_VERBOSE, "volume:(%f)(%1.2fdB) precision:%s\n",
vol->volume, 20.0*log(vol->volume)/M_LN10,
precision_str[vol->precision]);
}
return 0;
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)
@ -199,6 +233,37 @@ static av_cold void volume_init(VolumeContext *vol)
ff_volume_init_x86(vol);
}
static int set_volume(AVFilterContext *ctx)
{
VolumeContext *vol = ctx->priv;
vol->volume = av_expr_eval(vol->volume_pexpr, vol->var_values, NULL);
if (isnan(vol->volume)) {
if (vol->eval_mode == EVAL_MODE_ONCE) {
av_log(ctx, AV_LOG_ERROR, "Invalid value NaN for volume\n");
return AVERROR(EINVAL);
} else {
av_log(ctx, AV_LOG_WARNING, "Invalid value NaN for volume, setting to 0\n");
vol->volume = 0;
}
}
vol->var_values[VAR_VOLUME] = vol->volume;
if (vol->precision == PRECISION_FIXED) {
vol->volume_i = (int)(vol->volume * 256 + 0.5);
vol->volume = vol->volume_i / 256.0;
av_log(ctx, AV_LOG_VERBOSE, "volume:(%d/256)(%f)(%1.2fdB) precision:fixed\n",
vol->volume_i, vol->volume, 20.0*log(vol->volume)/M_LN10);
} else {
av_log(ctx, AV_LOG_VERBOSE, "volume:(%f)(%1.2fdB) precision:%s\n",
vol->volume, 20.0*log(vol->volume)/M_LN10,
precision_str[vol->precision]);
}
volume_init(vol);
return 0;
}
static int config_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
@ -209,20 +274,58 @@ static int config_output(AVFilterLink *outlink)
vol->channels = inlink->channels;
vol->planes = av_sample_fmt_is_planar(inlink->format) ? vol->channels : 1;
volume_init(vol);
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] =
vol->var_values[VAR_VOLUME] = NAN;
return 0;
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 nb_channels:%f\n",
vol->var_values[VAR_TB],
vol->var_values[VAR_SAMPLE_RATE],
vol->var_values[VAR_NB_CHANNELS]);
return set_volume(ctx);
}
#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->volume == 1.0 || vol->volume_i == 256)
return ff_filter_frame(outlink, buf);
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;
if (vol->eval_mode == EVAL_MODE_FRAME)
set_volume(ctx);
if (vol->volume == 1.0 || vol->volume_i == 256) {
out_buf = buf;
goto end;
}
/* do volume scaling in-place if input buffer is writable */
if (av_frame_is_writable(buf)) {
@ -266,6 +369,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
if (buf != out_buf)
av_frame_free(&buf);
end:
vol->var_values[VAR_NB_CONSUMED_SAMPLES] += buf->nb_samples;
return ff_filter_frame(outlink, out_buf);
}
@ -294,6 +399,7 @@ 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,

28
libavfilter/af_volume.h
View File

@ -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 +36,37 @@ enum PrecisionType {
PRECISION_DOUBLE,
};
enum EvalMode {
EVAL_MODE_ONCE,
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_VOLUME,
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;

2
libavfilter/version.h
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@ -31,7 +31,7 @@
#define LIBAVFILTER_VERSION_MAJOR 4
#define LIBAVFILTER_VERSION_MINOR 0
#define LIBAVFILTER_VERSION_MICRO 100
#define LIBAVFILTER_VERSION_MICRO 101
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \