[FFmpeg-devel] [PATCH 3/4] Add setpts filter, ported from the libavfilter soc repo.
Stefano Sabatini
stefano.sabatini-lala
Sun Oct 31 01:30:31 CEST 2010
---
doc/filters.texi | 66 ++++++++++++++++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_setpts.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 238 insertions(+), 0 deletions(-)
create mode 100644 libavfilter/vf_setpts.c
diff --git a/doc/filters.texi b/doc/filters.texi
index 157f621..19c4d29 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -502,6 +502,72 @@ settb=2*intb
settb=AVTB
@end example
+ at section setpts
+
+Change the PTS (presentation timestamp) of the input video frames.
+
+Accept in input an expression evaluated through the eval API, which
+can contain the following constants:
+
+ at table @option
+ at item PTS
+the presentation timestamp in input
+
+ at item PI
+Greek PI
+
+ at item PHI
+golden ratio
+
+ at item E
+Euler number
+
+ at item TBNUM, TBDEN
+input timebase numerator and denomimator
+
+ at item N
+the count of the input frame, starting from 0.
+
+ at item STARTPTS
+the PTS of the first video frame
+
+ at item INTERLACED
+tell if the current frame is interlaced
+
+ at item NOPTS
+1 if the input timestamp is undefined, 0 otherwise
+
+ at item POS
+original position in the file of the frame, or undefined if undefined
+for the current frame
+
+ at item PREV_INPTS
+previous input PTS
+
+ at item PREV_OUTPTS
+previous output PTS
+
+ at end table
+
+Some examples follow:
+
+ at example
+# start counting PTS from zero
+setpts=PTS-STARTPTS
+
+# fast motion
+setpts=0.5*PTS
+
+# slow motion
+setpts=2.0*PTS
+
+# fixed rate 25 fps
+setpts=N/(25*TB)
+
+# fixed rate 25 fps with some jitter
+setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
+ at end example
+
@section slicify
Pass the images of input video on to next video filter as multiple
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 38d2762..9dc92be 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -37,6 +37,7 @@ OBJS-$(CONFIG_PIXDESCTEST_FILTER) += vf_pixdesctest.o
OBJS-$(CONFIG_PIXELASPECT_FILTER) += vf_aspect.o
OBJS-$(CONFIG_SCALE_FILTER) += vf_scale.o
OBJS-$(CONFIG_SETTB_FILTER) += vf_settb.o
+OBJS-$(CONFIG_SETPTS_FILTER) += vf_setpts.o
OBJS-$(CONFIG_SLICIFY_FILTER) += vf_slicify.o
OBJS-$(CONFIG_TRANSPOSE_FILTER) += vf_transpose.o
OBJS-$(CONFIG_UNSHARP_FILTER) += vf_unsharp.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index bade1dd..8ba0b62 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -57,6 +57,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (PIXELASPECT, pixelaspect, vf);
REGISTER_FILTER (SCALE, scale, vf);
REGISTER_FILTER (SETTB, settb, vf);
+ REGISTER_FILTER (SETPTS, setpts, vf);
REGISTER_FILTER (SLICIFY, slicify, vf);
REGISTER_FILTER (TRANSPOSE, transpose, vf);
REGISTER_FILTER (UNSHARP, unsharp, vf);
diff --git a/libavfilter/vf_setpts.c b/libavfilter/vf_setpts.c
new file mode 100644
index 0000000..e0a9609
--- /dev/null
+++ b/libavfilter/vf_setpts.c
@@ -0,0 +1,170 @@
+/*
+ * 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
+ * video presentation timestamp (PTS) modification filter
+ */
+
+#define DEBUG
+
+#include "libavutil/eval.h"
+#include "avfilter.h"
+
+static const char *var_names[] = {
+ "E", ///< Euler number
+ "INTERLACED", ///< tell if the current frame is interlaced
+ "N", ///< frame number (starting at zero)
+ "NOPTS", ///< 1 if the input value is undefined, 0 otherwise
+ "PHI", ///< golden ratio
+ "PI", ///< greek pi
+ "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
+ "START_PTS", ///< PTS at start of movie
+ "TB", ///< timebase
+ "TBNUM", ///< timebase numerator
+ "TBDEN", ///< timebase denominator
+ NULL
+};
+
+enum var_name {
+ VAR_E,
+ VAR_INTERLACED,
+ VAR_N,
+ VAR_NOPTS,
+ VAR_PHI,
+ VAR_PI,
+ VAR_POS,
+ VAR_PREV_INPTS,
+ VAR_PREV_OUTPTS,
+ VAR_PTS,
+ VAR_START_PTS,
+ VAR_TB,
+ VAR_TBNUM,
+ VAR_TBDEN,
+ 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_parse_expr(&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_E ] = M_E;
+ setpts->var_values[VAR_N ] = 0.0;
+ setpts->var_values[VAR_NOPTS ] = NAN;
+ setpts->var_values[VAR_PHI ] = M_PHI;
+ setpts->var_values[VAR_PI ] = M_PI;
+ setpts->var_values[VAR_PREV_INPTS ] = NAN;
+ setpts->var_values[VAR_PREV_OUTPTS] = NAN;
+ setpts->var_values[VAR_START_PTS ] = NAN;
+ return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+ SetPTSContext *setpts = inlink->dst->priv;
+
+ setpts->var_values[VAR_TB] = (double)inlink->time_base.num/inlink->time_base.den;
+ setpts->var_values[VAR_TBNUM] = inlink->time_base.num;
+ setpts->var_values[VAR_TBDEN] = inlink->time_base.den;
+
+ av_log(inlink->src, AV_LOG_INFO, "TB:%f TBNUM:%d TBDEN:%d\n",
+ setpts->var_values[VAR_TB], inlink->time_base.num, inlink->time_base.den);
+ 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 start_frame(AVFilterLink *inlink, AVFilterBufferRef *inpicref)
+{
+ SetPTSContext *setpts = inlink->dst->priv;
+ double d;
+ AVFilterBufferRef *outpicref = avfilter_ref_buffer(inpicref, ~0);
+
+ if (isnan(setpts->var_values[VAR_START_PTS]))
+ setpts->var_values[VAR_START_PTS] = TS2D(inpicref->pts);
+
+ setpts->var_values[VAR_INTERLACED] = inpicref->video->interlaced;
+ setpts->var_values[VAR_NOPTS ] = inpicref->pts == AV_NOPTS_VALUE;
+ setpts->var_values[VAR_PTS ] = TS2D(inpicref->pts);
+ setpts->var_values[VAR_POS ] = inpicref->pos == -1 ? NAN : inpicref->pos;
+
+ d = av_eval_expr(setpts->expr, setpts->var_values, NULL);
+ outpicref->pts = D2TS(d);
+
+#ifdef DEBUG
+ av_log(inlink->dst, AV_LOG_DEBUG,
+ "n:%"PRId64" interlaced:%d pos:%d pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
+ (int64_t)setpts->var_values[VAR_N],
+ (int)setpts->var_values[VAR_INTERLACED],
+ (int)setpts->var_values[VAR_POS],
+ inpicref ->pts,
+ (double)inpicref->pts * inlink->time_base.num / inlink->time_base.den,
+ outpicref->pts,
+ (double)outpicref->pts * inlink->time_base.num / inlink->time_base.den);
+#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_start_frame(inlink->dst->outputs[0], outpicref);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ SetPTSContext *setpts = ctx->priv;
+ av_free_expr(setpts->expr);
+ setpts->expr = NULL;
+}
+
+AVFilter avfilter_vf_setpts = {
+ .name = "setpts",
+ .description = NULL_IF_CONFIG_SMALL("Set PTS for the output video frame."),
+ .init = init,
+ .uninit = uninit,
+
+ .priv_size = sizeof(SetPTSContext),
+
+ .inputs = (AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .get_video_buffer = avfilter_null_get_video_buffer,
+ .config_props = config_input,
+ .start_frame = start_frame, },
+ { .name = NULL }},
+ .outputs = (AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO, },
+ { .name = NULL}},
+};
--
1.7.1
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