It accepts the following values:
@table @samp
@item once
-only evaluate expression once during the filter initialization
+only evaluate expression once during the filter initialization, or
+when the @samp{volume} command is sent
@item frame
evaluate expression for each incoming frame
@var{sample_rate} and @var{tb} variables are available, all other
variables will evaluate to NAN.
+@subsection Commands
+
+This filter supports the following commands:
+@table @option
+@item volume
+Modify the volume expression.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+@end table
+
@subsection Examples
@itemize
return set_volume(ctx);
}
+static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
+ char *res, int res_len, int flags)
+{
+ VolumeContext *vol = ctx->priv;
+ int ret = AVERROR(ENOSYS);
+
+ if (!strcmp(cmd, "volume")) {
+ if ((ret = set_expr(&vol->volume_pexpr, args, ctx)) < 0)
+ return ret;
+ if (vol->eval_mode == EVAL_MODE_ONCE)
+ set_volume(ctx);
+ }
+
+ return ret;
+}
+
#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))
.inputs = avfilter_af_volume_inputs,
.outputs = avfilter_af_volume_outputs,
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
+ .process_command = process_command,
};
#define LIBAVFILTER_VERSION_MAJOR 4
#define LIBAVFILTER_VERSION_MINOR 0
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \