[FFmpeg-devel] [PATCH 6/7] Implement settb filter.

[Stefano Sabatini]

---
 doc/filters.texi         |   19 +++++++++
 libavfilter/Makefile     |    1 +
 libavfilter/allfilters.c |    1 +
 libavfilter/vf_settb.c   |   92 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 113 insertions(+), 0 deletions(-)
 create mode 100644 libavfilter/vf_settb.c

diff --git a/doc/filters.texi b/doc/filters.texi
index 6b0a85c..542cc23 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -149,6 +149,25 @@ ratio of the input image.
 
 The default value of @var{width} and @var{height} is 0.
 
+ at section settb
+
+Set the timebase to use for the output frames timestamps.
+
+It accepts in input a string of the form @var{num}:@var{den}, where
+ at var{num} and @var{den} correspond to the numerator and denominator of
+the timebase to set. If they are not specified they are set to 0.
+
+In the case both @var{num} and @var{den} are not specified or are
+explicitely set to 0, then the filter will use for the output the same
+timebase as used for the input (thus acting as a null filter).
+
+For example:
+ at example
+settb=1:25
+ at end example
+
+will set the timebase to 1/25.
+
 @section slicify
 
 Pass the images of input video on to next video filter as multiple
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index c2c1a21..f9a706d 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -23,6 +23,7 @@ OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
 OBJS-$(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_SLICIFY_FILTER)                += vf_slicify.o
 OBJS-$(CONFIG_UNSHARP_FILTER)                += vf_unsharp.o
 OBJS-$(CONFIG_VFLIP_FILTER)                  += vf_vflip.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index e8bc771..cede501 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -43,6 +43,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (PIXDESCTEST, pixdesctest, vf);
     REGISTER_FILTER (PIXELASPECT, pixelaspect, vf);
     REGISTER_FILTER (SCALE,       scale,       vf);
+    REGISTER_FILTER (SETTB,       settb,       vf);
     REGISTER_FILTER (SLICIFY,     slicify,     vf);
     REGISTER_FILTER (UNSHARP,     unsharp,     vf);
     REGISTER_FILTER (VFLIP,       vflip,       vf);
diff --git a/libavfilter/vf_settb.c b/libavfilter/vf_settb.c
new file mode 100644
index 0000000..483fdea
--- /dev/null
+++ b/libavfilter/vf_settb.c
@@ -0,0 +1,92 @@
+/*
+ * copyright (c) 2010 Stefano Sabatini
+ *
+ * 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
+ * Set timebase for the output link.
+ */
+
+#include "libavutil/rational.h"
+#include "avfilter.h"
+#include "internal.h"
+
+typedef struct {
+    AVRational time_base;
+} SetTBContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    SetTBContext *settb = ctx->priv;
+
+    settb->time_base = (AVRational) {0,0};
+    if (args)
+        sscanf(args, "%d:%d", &(settb->time_base.num), &(settb->time_base.den));
+
+    return 0;
+}
+
+static int config_input_props(AVFilterLink *inlink)
+{
+    SetTBContext *settb = inlink->dst->priv;
+
+    if (settb->time_base.num == 0 && settb->time_base.den == 0) {
+        settb->time_base = link_spad(inlink).time_base;
+    } else if (settb->time_base.num <= 0 || settb->time_base.den <= 0) {
+        av_log(inlink->dst, AV_LOG_ERROR, "Invalid value %d/%d set for the output timebase\n",
+               settb->time_base.num, settb->time_base.den);
+        return AVERROR(EINVAL);
+    }
+
+    link_dpad(inlink).time_base = settb->time_base;
+    return 0;
+}
+
+static int config_output_props(AVFilterLink *outlink)
+{
+    SetTBContext *settb = outlink->src->priv;
+    AVFilterLink *inlink = outlink->src->inputs[0];
+
+    outlink->w = inlink->w;
+    outlink->h = inlink->h;
+    link_spad(outlink).time_base = settb->time_base;
+
+    return 0;
+}
+
+AVFilter avfilter_vf_settb = {
+    .name      = "settb",
+    .description = NULL_IF_CONFIG_SMALL("Set timebase for the output link."),
+    .init      = init,
+
+    .priv_size = sizeof(SetTBContext),
+
+    .inputs    = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO,
+                                    .config_props     = config_input_props,
+                                    .get_video_buffer = avfilter_null_get_video_buffer,
+                                    .start_frame      = avfilter_null_start_frame,
+                                    .end_frame        = avfilter_null_end_frame },
+                                  { .name = NULL }},
+
+    .outputs   = (AVFilterPad[]) {{ .name            = "default",
+                                    .type            = AVMEDIA_TYPE_VIDEO,
+                                    .config_props    = config_output_props, },
+                                  { .name = NULL}},
+};
-- 
1.6.0.4