lavfi: add an asetpts filter

1 files changed, 261 insertions, 0 deletions

diff --git a/libavfilter/setpts.c b/libavfilter/setpts.c
new file mode 100644
index 0000000000..7a1f4f31d8
--- /dev/null
+++ b/libavfilter/setpts.c
@@ -0,0 +1,261 @@
+/*
+ * Copyright (c) 2010 Stefano Sabatini
+ * Copyright (c) 2008 Victor Paesa
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; 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 "libavutil/internal.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/opt.h"
+#include "libavutil/time.h"
+
+#include "audio.h"
+#include "avfilter.h"
+#include "internal.h"
+#include "video.h"
+
+#include "config.h"
+
+static const char *const var_names[] = {
+    "E",           ///< Euler number
+    "INTERLACED",  ///< tell if the current frame is interlaced
+    "N",           ///< frame / sample number (starting at zero)
+    "PHI",         ///< golden ratio
+    "PI",          ///< greek pi
+    "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
+    "RTCTIME",     ///< wallclock (RTC) time in micro seconds
+    "RTCSTART",    ///< wallclock (RTC) time at the start of the movie in micro seconds
+    "S",           //   Number of samples in the current frame
+    "SR",          //   Audio sample rate
+    NULL
+};
+
+enum var_name {
+    VAR_E,
+    VAR_INTERLACED,
+    VAR_N,
+    VAR_PHI,
+    VAR_PI,
+    VAR_PREV_INPTS,
+    VAR_PREV_OUTPTS,
+    VAR_PTS,
+    VAR_STARTPTS,
+    VAR_TB,
+    VAR_RTCTIME,
+    VAR_RTCSTART,
+    VAR_S,
+    VAR_SR,
+    VAR_VARS_NB
+};
+
+typedef struct {
+    const AVClass *class;
+    char *expr_str;
+    AVExpr *expr;
+    double var_values[VAR_VARS_NB];
+} SetPTSContext;
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    SetPTSContext *setpts = ctx->priv;
+    int ret;
+
+    if ((ret = av_expr_parse(&setpts->expr, setpts->expr_str,
+                             var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
+        av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", setpts->expr_str);
+        return ret;
+    }
+
+    setpts->var_values[VAR_E]           = M_E;
+    setpts->var_values[VAR_N]           = 0.0;
+    setpts->var_values[VAR_S]           = 0.0;
+    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_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);
+    setpts->var_values[VAR_RTCSTART] = av_gettime();
+
+    if (inlink->type == AVMEDIA_TYPE_AUDIO) {
+        setpts->var_values[VAR_SR] = inlink->sample_rate;
+    }
+
+    av_log(inlink->src, AV_LOG_VERBOSE, "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 int filter_frame(AVFilterLink *inlink, AVFrame *frame)
+{
+    SetPTSContext *setpts = inlink->dst->priv;
+    int64_t in_pts = frame->pts;
+    double d;
+
+    if (isnan(setpts->var_values[VAR_STARTPTS]))
+        setpts->var_values[VAR_STARTPTS] = TS2D(frame->pts);
+
+    setpts->var_values[VAR_PTS       ] = TS2D(frame->pts);
+    setpts->var_values[VAR_RTCTIME   ] = av_gettime();
+
+    if (inlink->type == AVMEDIA_TYPE_VIDEO) {
+        setpts->var_values[VAR_INTERLACED] = frame->interlaced_frame;
+    } else {
+        setpts->var_values[VAR_S] = frame->nb_samples;
+    }
+
+    d = av_expr_eval(setpts->expr, setpts->var_values, NULL);
+    frame->pts = D2TS(d);
+
+#ifdef DEBUG
+    av_log(inlink->dst, AV_LOG_DEBUG,
+           "n:%"PRId64" interlaced:%d pts:%"PRId64" t:%f -> pts:%"PRId64" t:%f\n",
+           (int64_t)setpts->var_values[VAR_N],
+           (int)setpts->var_values[VAR_INTERLACED],
+           in_pts, in_pts * av_q2d(inlink->time_base),
+           frame->pts, frame->pts * av_q2d(inlink->time_base));
+#endif
+
+
+    if (inlink->type == AVMEDIA_TYPE_VIDEO) {
+        setpts->var_values[VAR_N] += 1.0;
+    } else {
+        setpts->var_values[VAR_N] += frame->nb_samples;
+    }
+
+    setpts->var_values[VAR_PREV_INPTS ] = TS2D(in_pts);
+    setpts->var_values[VAR_PREV_OUTPTS] = TS2D(frame->pts);
+    return ff_filter_frame(inlink->dst->outputs[0], frame);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    SetPTSContext *setpts = ctx->priv;
+    av_expr_free(setpts->expr);
+    setpts->expr = NULL;
+}
+
+#define OFFSET(x) offsetof(SetPTSContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_AUDIO_PARAM
+static const AVOption options[] = {
+    { "expr", "Expression determining the frame timestamp", OFFSET(expr_str), AV_OPT_TYPE_STRING, { .str = "PTS" }, .flags = FLAGS },
+    { NULL },
+};
+
+#if CONFIG_SETPTS_FILTER
+static const AVClass setpts_class = {
+    .class_name = "setpts",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static const AVFilterPad avfilter_vf_setpts_inputs[] = {
+    {
+        .name             = "default",
+        .type             = AVMEDIA_TYPE_VIDEO,
+        .get_video_buffer = ff_null_get_video_buffer,
+        .config_props     = config_input,
+        .filter_frame     = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad avfilter_vf_setpts_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { 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),
+    .priv_class = &setpts_class,
+
+    .inputs    = avfilter_vf_setpts_inputs,
+    .outputs   = avfilter_vf_setpts_outputs,
+};
+#endif
+
+#if CONFIG_ASETPTS_FILTER
+static const AVClass asetpts_class = {
+    .class_name = "asetpts",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static const AVFilterPad asetpts_inputs[] = {
+    {
+        .name             = "default",
+        .type             = AVMEDIA_TYPE_AUDIO,
+        .get_audio_buffer = ff_null_get_audio_buffer,
+        .config_props     = config_input,
+        .filter_frame     = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad asetpts_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_AUDIO,
+    },
+    { 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),
+    .priv_class = &asetpts_class,
+
+    .inputs    = asetpts_inputs,
+    .outputs   = asetpts_outputs,
+};
+#endif