Implement settb filter.

Originally committed as revision 25445 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 141 insertions, 0 deletions

diff --git a/libavfilter/vf_settb.c b/libavfilter/vf_settb.c
new file mode 100644
index 0000000000..1a8724bd22
--- /dev/null
+++ b/libavfilter/vf_settb.c
@@ -0,0 +1,141 @@
+/*
+ * 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/avstring.h"
+#include "libavutil/eval.h"
+#include "libavutil/rational.h"
+#include "avfilter.h"
+#include "internal.h"
+
+static const char *var_names[] = {
+    "E",
+    "PHI",
+    "PI",
+    "AVTB",   /* default timebase 1/AV_TIME_BASE */
+    "intb",   /* input timebase */
+    NULL
+};
+
+enum var_name {
+    VAR_E,
+    VAR_PHI,
+    VAR_PI,
+    VAR_AVTB,
+    VAR_INTB,
+    VAR_VARS_NB
+};
+
+typedef struct {
+    char tb_expr[256];
+    double var_values[VAR_VARS_NB];
+} SetTBContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    SetTBContext *settb = ctx->priv;
+    av_strlcpy(settb->tb_expr, "intb", sizeof(settb->tb_expr));
+
+    if (args)
+        sscanf(args, "%255[^:]", settb->tb_expr);
+
+    return 0;
+}
+
+static int config_output_props(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    SetTBContext *settb = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    AVRational time_base;
+    int ret;
+    double res;
+
+    settb->var_values[VAR_E]    = M_E;
+    settb->var_values[VAR_PHI]  = M_PHI;
+    settb->var_values[VAR_PI]   = M_PI;
+    settb->var_values[VAR_AVTB] = av_q2d(AV_TIME_BASE_Q);
+    settb->var_values[VAR_INTB] = av_q2d(inlink->time_base);
+
+    outlink->w = inlink->w;
+    outlink->h = inlink->h;
+
+    if ((ret = av_parse_and_eval_expr(&res, settb->tb_expr, var_names, settb->var_values,
+                                      NULL, NULL, NULL, NULL, NULL, 0, NULL)) < 0) {
+        av_log(ctx, AV_LOG_ERROR, "Invalid expression '%s' for timebase.\n", settb->tb_expr);
+        return ret;
+    }
+    time_base = av_d2q(res, INT_MAX);
+    if (time_base.num <= 0 || time_base.den <= 0) {
+        av_log(ctx, AV_LOG_ERROR,
+               "Invalid non-positive values for the timebase num:%d or den:%d.\n",
+               time_base.num, time_base.den);
+        return AVERROR(EINVAL);
+    }
+
+    outlink->time_base = time_base;
+    av_log(outlink->src, AV_LOG_INFO, "tb:%d/%d -> tb:%d/%d\n",
+           inlink ->time_base.num, inlink ->time_base.den,
+           outlink->time_base.num, outlink->time_base.den);
+
+    return 0;
+}
+
+static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFilterBufferRef *picref2 = picref;
+
+    if (av_cmp_q(inlink->time_base, outlink->time_base)) {
+        picref2 = avfilter_ref_buffer(picref, ~0);
+        picref2->pts = av_rescale_q(picref->pts, inlink->time_base, outlink->time_base);
+        av_log(ctx, AV_LOG_DEBUG, "tb:%d/%d pts:%"PRId64" -> tb:%d/%d pts:%"PRId64"\n",
+               inlink ->time_base.num, inlink ->time_base.den, picref ->pts,
+               outlink->time_base.num, outlink->time_base.den, picref2->pts);
+        avfilter_unref_buffer(picref);
+    }
+
+    avfilter_start_frame(outlink, picref2);
+}
+
+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,
+                                    .get_video_buffer = avfilter_null_get_video_buffer,
+                                    .start_frame      = 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}},
+};