lavfi: add realtime filter.

Similar to the -re option in ffmpeg that only works for input files.
Can be used at any place in the filter graph.

1 files changed, 132 insertions, 0 deletions

diff --git a/libavfilter/f_realtime.c b/libavfilter/f_realtime.c
new file mode 100644
index 0000000000..68ad268523
--- /dev/null
+++ b/libavfilter/f_realtime.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2015 Nicolas George
+ *
+ * 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
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/time.h"
+#include "avfilter.h"
+#include "internal.h"
+
+typedef struct RealtimeContext {
+    const AVClass *class;
+    int64_t delta;
+    int64_t limit;
+    unsigned inited;
+} RealtimeContext;
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    AVFilterContext *ctx = inlink->dst;
+    RealtimeContext *s = ctx->priv;
+
+    if (frame->pts != AV_NOPTS_VALUE) {
+        int64_t pts = av_rescale_q(frame->pts, inlink->time_base, AV_TIME_BASE_Q);
+        int64_t now = av_gettime_relative();
+        int64_t sleep = pts - now + s->delta;
+        if (!s->inited) {
+            s->inited = 1;
+            sleep = 0;
+            s->delta = now - pts;
+        }
+        if (sleep > s->limit || sleep < -s->limit) {
+            av_log(ctx, AV_LOG_WARNING,
+                   "time discontinuity detected: %"PRIi64" us, resetting\n",
+                   sleep);
+            sleep = 0;
+            s->delta = now - pts;
+        }
+        if (sleep > 0) {
+            av_log(ctx, AV_LOG_DEBUG, "sleeping %"PRIi64" us\n", sleep);
+            for (; sleep > 600000000; sleep -= 600000000)
+                av_usleep(600000000);
+            av_usleep(sleep);
+        }
+    }
+    return ff_filter_frame(inlink->dst->outputs[0], frame);
+}
+
+#define OFFSET(x) offsetof(RealtimeContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM
+static const AVOption options[] = {
+    { "limit", "sleep time limit", OFFSET(limit), AV_OPT_TYPE_DURATION, { .i64 = 2000000 }, 0, INT64_MAX, FLAGS },
+    { NULL }
+};
+
+#if CONFIG_REALTIME_FILTER
+#define realtime_options options
+AVFILTER_DEFINE_CLASS(realtime);
+
+static const AVFilterPad avfilter_vf_realtime_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad avfilter_vf_realtime_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_realtime = {
+    .name        = "realtime",
+    .description = NULL_IF_CONFIG_SMALL("Slow down filtering to match realtime"),
+    .priv_size   = sizeof(RealtimeContext),
+    .priv_class  = &realtime_class,
+    .inputs      = avfilter_vf_realtime_inputs,
+    .outputs     = avfilter_vf_realtime_outputs,
+};
+#endif /* CONFIG_REALTIME_FILTER */
+
+#if CONFIG_AREALTIME_FILTER
+
+#define arealtime_options options
+AVFILTER_DEFINE_CLASS(arealtime);
+
+static const AVFilterPad arealtime_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_AUDIO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad arealtime_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { NULL }
+};
+
+AVFilter ff_af_arealtime = {
+    .name        = "arealtime",
+    .description = NULL_IF_CONFIG_SMALL("Slow down filtering to match realtime"),
+    .priv_size   = sizeof(RealtimeContext),
+    .priv_class  = &arealtime_class,
+    .inputs      = arealtime_inputs,
+    .outputs     = arealtime_outputs,
+};
+#endif /* CONFIG_AREALTIME_FILTER */