[FFmpeg-devel] [PATCH] Add asetpts audio filter
Andrey Utkin
andrey.krieger.utkin at gmail.com
Wed Feb 29 13:00:01 CET 2012
---
libavfilter/Makefile | 1 +
libavfilter/af_asetpts.c | 145 ++++++++++++++++++++++++++++++++++++++++++++++
libavfilter/allfilters.c | 1 +
3 files changed, 147 insertions(+), 0 deletions(-)
create mode 100644 libavfilter/af_asetpts.c
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index db7397b..37e006e 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -31,6 +31,7 @@ OBJS-$(CONFIG_AFORMAT_FILTER) += af_aformat.o
OBJS-$(CONFIG_AMERGE_FILTER) += af_amerge.o
OBJS-$(CONFIG_ANULL_FILTER) += af_anull.o
OBJS-$(CONFIG_ARESAMPLE_FILTER) += af_aresample.o
+OBJS-$(CONFIG_ASETPTS_FILTER) += af_asetpts.o
OBJS-$(CONFIG_ASHOWINFO_FILTER) += af_ashowinfo.o
OBJS-$(CONFIG_ASPLIT_FILTER) += af_asplit.o
OBJS-$(CONFIG_ASTREAMSYNC_FILTER) += af_astreamsync.o
diff --git a/libavfilter/af_asetpts.c b/libavfilter/af_asetpts.c
new file mode 100644
index 0000000..ed15f9b
--- /dev/null
+++ b/libavfilter/af_asetpts.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2012 Andrey Utkin
+ * Copyright (c) 2010 Stefano Sabatini
+ * Copyright (c) 2008 Victor Paesa
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * audio presentation timestamp (PTS) modification filter
+ */
+
+/* #define DEBUG */
+
+#include "libavutil/eval.h"
+#include "libavutil/mathematics.h"
+#include "avfilter.h"
+
+static const char *const var_names[] = {
+ "N", ///< frame number (starting at zero)
+ "POS", ///< original position in the file of the frame
+ "PREV_INPTS", ///< previous input PTS
+ "PREV_OUTPTS", ///< previous output PTS
+ "PTS", ///< original pts in the file of the frame
+ "STARTPTS", ///< PTS at start of movie
+ "TB", ///< timebase
+ NULL
+};
+
+enum var_name {
+ VAR_N,
+ VAR_POS,
+ VAR_PREV_INPTS,
+ VAR_PREV_OUTPTS,
+ VAR_PTS,
+ VAR_STARTPTS,
+ VAR_TB,
+ VAR_VARS_NB
+};
+
+typedef struct {
+ AVExpr *expr;
+ double var_values[VAR_VARS_NB];
+} SetPTSContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+ SetPTSContext *setpts = ctx->priv;
+ int ret;
+
+ if ((ret = av_expr_parse(&setpts->expr, args ? args : "PTS",
+ var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
+ return ret;
+ }
+
+ setpts->var_values[VAR_N ] = 0.0;
+ setpts->var_values[VAR_PREV_INPTS ] = NAN;
+ setpts->var_values[VAR_PREV_OUTPTS] = NAN;
+ setpts->var_values[VAR_STARTPTS ] = NAN;
+ return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+ SetPTSContext *setpts = inlink->dst->priv;
+
+ setpts->var_values[VAR_TB] = av_q2d(inlink->time_base);
+
+ av_log(inlink->src, AV_LOG_INFO, "TB:%f\n", setpts->var_values[VAR_TB]);
+ return 0;
+}
+
+#define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
+#define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
+
+static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
+{
+ SetPTSContext *setpts = inlink->dst->priv;
+ double d;
+ AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
+
+ if (isnan(setpts->var_values[VAR_STARTPTS]))
+ setpts->var_values[VAR_STARTPTS] = TS2D(inpicref->pts);
+
+ setpts->var_values[VAR_PTS] = TS2D(inpicref->pts);
+ setpts->var_values[VAR_POS] = inpicref->pos == -1 ? NAN : inpicref->pos;
+
+ d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
+ outpicref->pts = D2TS(d);
+
+#ifdef DEBUG
+ av_log(inlink->dst, AV_LOG_DEBUG,
+ "n:%"PRId64" pos:%"PRId64" pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
+ (int64_t)setpts->var_values[VAR_N],
+ inpicref ->pos,
+ inpicref ->pts, inpicref ->pts * av_q2d(inlink->time_base),
+ outpicref->pts, outpicref->pts * av_q2d(inlink->time_base));
+#endif
+
+ setpts->var_values[VAR_N] += 1.0;
+ setpts->var_values[VAR_PREV_INPTS ] = TS2D(inpicref ->pts);
+ setpts->var_values[VAR_PREV_OUTPTS] = TS2D(outpicref->pts);
+ avfilter_filter_samples(inlink->dst->outputs[0], outpicref);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ SetPTSContext *setpts = ctx->priv;
+ av_expr_free(setpts->expr);
+ setpts->expr = NULL;
+}
+
+AVFilter avfilter_af_asetpts = {
+ .name = "asetpts",
+ .description = NULL_IF_CONFIG_SMALL("Set PTS for the output audio frame."),
+ .init = init,
+ .uninit = uninit,
+
+ .priv_size = sizeof(SetPTSContext),
+
+ .inputs = (const AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .config_props = config_input,
+ .filter_samples = filter_samples, },
+ { .name = NULL }},
+ .outputs = (const AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO, },
+ { .name = NULL}},
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 339ef8d..b7dd730 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -39,6 +39,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (AMERGE, amerge, af);
REGISTER_FILTER (ANULL, anull, af);
REGISTER_FILTER (ARESAMPLE, aresample, af);
+ REGISTER_FILTER (ASETPTS, asetpts, af);
REGISTER_FILTER (ASHOWINFO, ashowinfo, af);
REGISTER_FILTER (ASPLIT, asplit, af);
REGISTER_FILTER (ASTREAMSYNC, astreamsync, af);
--
1.7.7
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