[FFmpeg-devel] [PATCH 2/2] libavfilter/vf_fps: Rewrite using activate callback
Calvin Walton
calvin.walton at kepstin.ca
Fri Feb 16 22:02:17 EET 2018
The old version of the filter had a problem where it would queue up
all of the duplicate frames required to fill a timestamp gap in a
single call to filter_frame. In problematic files - I've hit this in
webcam streams with large gaps due to network issues - this will queue
up a potentially huge number of frames. (I've seen it trigger the Linux
OOM-killer on particularly large pts gaps.)
This revised version of the filter using the activate callback will
generate at most 1 frame each time it is called, and respects output
links having the frame_wanted_out set to a negative number to indicate
that they don't want frames.
TODO: This is still a work in progress. It may have different behaviour
in some cases from the old fps filter. I have not yet implemented the
"eof_action" option, since I haven't figured out what it's supposed to
do.
---
libavfilter/vf_fps.c | 398 +++++++++++++++++++++++++++++----------------------
1 file changed, 230 insertions(+), 168 deletions(-)
diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
index dbafd2c35a..16e432db0b 100644
--- a/libavfilter/vf_fps.c
+++ b/libavfilter/vf_fps.c
@@ -2,6 +2,7 @@
* Copyright 2007 Bobby Bingham
* Copyright 2012 Robert Nagy <ronag89 gmail com>
* Copyright 2012 Anton Khirnov <anton khirnov net>
+ * Copyright 2018 Calvin Walton <calvin.walton at kepstin.ca>
*
* This file is part of FFmpeg.
*
@@ -28,17 +29,12 @@
#include <float.h>
#include <stdint.h>
-#include "libavutil/common.h"
-#include "libavutil/fifo.h"
+#include "libavutil/avassert.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
-#include "libavutil/parseutils.h"
-
-#define FF_INTERNAL_FIELDS 1
-#include "framequeue.h"
#include "avfilter.h"
+#include "filters.h"
#include "internal.h"
-#include "video.h"
enum EOFAction {
EOF_ACTION_ROUND,
@@ -49,17 +45,24 @@ enum EOFAction {
typedef struct FPSContext {
const AVClass *class;
- AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
-
- /* timestamps in input timebase */
- int64_t first_pts; ///< pts of the first frame that arrived on this filter
-
+ /* Options */
double start_time; ///< pts, in seconds, of the expected first frame
-
AVRational framerate; ///< target framerate
int rounding; ///< AVRounding method for timestamps
int eof_action; ///< action performed for last frame in FIFO
+ /* Set during outlink configuration */
+ int64_t start_pts; ///< pts of the expected first frame
+
+ /* Runtime state */
+ int status; ///< buffered input status
+ int64_t status_pts; ///< buffered input status timestamp
+
+ AVFrame *frames[2]; ///< buffered frames
+ int frames_count; ///< number of buffered frames
+
+ int64_t next_pts; ///< pts of the next frame to output
+
/* statistics */
int frames_in; ///< number of frames on input
int frames_out; ///< number of frames on output
@@ -91,31 +94,46 @@ static av_cold int init(AVFilterContext *ctx)
{
FPSContext *s = ctx->priv;
- if (!(s->fifo = av_fifo_alloc_array(2, sizeof(AVFrame*))))
- return AVERROR(ENOMEM);
+ /* Pass INT64_MIN/MAX through unchanged to avoid special cases for AV_NOPTS_VALUE */
+ s->rounding = s->rounding | AV_ROUND_PASS_MINMAX;
- s->first_pts = AV_NOPTS_VALUE;
+ s->start_pts = AV_NOPTS_VALUE;
+ s->status_pts = AV_NOPTS_VALUE;
+ s->next_pts = AV_NOPTS_VALUE;
av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
return 0;
}
-static void flush_fifo(AVFifoBuffer *fifo)
+/* Remove the first frame from the buffer, returning it */
+static AVFrame *shift_frame(FPSContext *s)
{
- while (av_fifo_size(fifo)) {
- AVFrame *tmp;
- av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
- av_frame_free(&tmp);
- }
+ AVFrame *frame;
+
+ /* Must only be called when there are frames in the buffer */
+ av_assert1(s->frames_count > 0);
+
+ frame = s->frames[0];
+ s->frames[0] = s->frames[1];
+ s->frames[1] = NULL;
+ s->frames_count--;
+
+ return frame;
}
static av_cold void uninit(AVFilterContext *ctx)
{
FPSContext *s = ctx->priv;
- if (s->fifo) {
- s->drop += av_fifo_size(s->fifo) / sizeof(AVFrame*);
- flush_fifo(s->fifo);
- av_fifo_freep(&s->fifo);
+
+ AVFrame *frame;
+
+ /* Free any remaining buffered frames. This only happens if a downstream
+ * filter has asked us to stop, so don't count them as dropped. */
+ av_log(ctx, AV_LOG_DEBUG, "Discarding %d buffered frame(s) at exit.\n",
+ s->frames_count);
+ while (s->frames_count > 0) {
+ frame = shift_frame(s);
+ av_frame_free(&frame);
}
av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
@@ -128,194 +146,238 @@ static int config_props(AVFilterLink* link)
link->time_base = av_inv_q(s->framerate);
link->frame_rate= s->framerate;
- link->w = link->src->inputs[0]->w;
- link->h = link->src->inputs[0]->h;
+
+ /* Convert the start time option to output timebase and save it */
+ if (s->start_time != DBL_MAX && s->start_time != AV_NOPTS_VALUE) {
+ double first_pts = s->start_time * AV_TIME_BASE;
+ first_pts = FFMIN(FFMAX(first_pts, INT64_MIN), INT64_MAX);
+ s->start_pts = av_rescale_q_rnd(first_pts, AV_TIME_BASE_Q,
+ link->time_base, s->rounding);
+ }
return 0;
}
-static int request_frame(AVFilterLink *outlink)
+/* Read a frame from the input and save it in the buffer */
+static void read_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink)
{
- AVFilterContext *ctx = outlink->src;
- FPSContext *s = ctx->priv;
+ AVFrame *frame;
int ret;
+ int64_t in_pts;
- ret = ff_request_frame(ctx->inputs[0]);
-
- /* flush the fifo */
- if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
- int i;
- for (i = 0; av_fifo_size(s->fifo); i++) {
- AVFrame *buf;
-
- av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
- if (av_fifo_size(s->fifo)) {
- buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
- outlink->time_base) + s->frames_out;
-
- if ((ret = ff_filter_frame(outlink, buf)) < 0)
- return ret;
-
- s->frames_out++;
- } else {
- /* This is the last frame, we may have to duplicate it to match
- * the last frame duration */
- int j;
- int eof_rounding = (s->eof_action == EOF_ACTION_PASS) ? AV_ROUND_UP : s->rounding;
- int delta = av_rescale_q_rnd(ctx->inputs[0]->current_pts - s->first_pts,
- ctx->inputs[0]->time_base,
- outlink->time_base, eof_rounding) - s->frames_out;
- av_log(ctx, AV_LOG_DEBUG, "EOF frames_out:%d delta:%d\n", s->frames_out, delta);
- /* if the delta is equal to 1, it means we just need to output
- * the last frame. Greater than 1 means we will need duplicate
- * delta-1 frames */
- if (delta > 0 ) {
- for (j = 0; j < delta; j++) {
- AVFrame *dup = av_frame_clone(buf);
-
- av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
- dup->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
- outlink->time_base) + s->frames_out;
-
- if ((ret = ff_filter_frame(outlink, dup)) < 0)
- return ret;
-
- s->frames_out++;
- if (j > 0) s->dup++;
- }
- av_frame_free(&buf);
- } else {
- /* for delta less or equal to 0, we should drop the frame,
- * otherwise, we will have one or more extra frames */
- av_frame_free(&buf);
- s->drop++;
- }
- }
- }
- return 0;
- }
+ /* Must only be called when we have buffer room available */
+ av_assert1(s->frames_count < 2);
- return ret;
-}
+ ret = ff_inlink_consume_frame(inlink, &frame);
+ /* Caller must have run ff_inlink_check_available_frame first */
+ av_assert1(ret);
-static int write_to_fifo(AVFifoBuffer *fifo, AVFrame *buf)
-{
- int ret;
+ /* Convert frame pts to output timebase */
+ in_pts = frame->pts;
+ frame->pts = av_rescale_q_rnd(in_pts, inlink->time_base,
+ outlink->time_base, s->rounding);
- if (!av_fifo_space(fifo) &&
- (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {
- av_frame_free(&buf);
- return ret;
- }
+ av_log(ctx, AV_LOG_DEBUG, "Read frame with in pts %"PRId64", out pts %"PRId64"\n",
+ in_pts, frame->pts);
- av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
- return 0;
+ s->frames[s->frames_count++] = frame;
+ s->frames_in++;
}
-static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
+/* Write a frame to the output */
+static int write_frame(AVFilterContext *ctx, FPSContext *s, AVFilterLink *outlink)
{
- AVFilterContext *ctx = inlink->dst;
- FPSContext *s = ctx->priv;
- AVFilterLink *outlink = ctx->outputs[0];
- int64_t delta;
- int i, ret;
+ AVFrame *frame;
+ int ret;
+ int dup = 0;
- s->frames_in++;
- /* discard frames until we get the first timestamp */
- if (s->first_pts == AV_NOPTS_VALUE) {
- if (buf->pts != AV_NOPTS_VALUE) {
- ret = write_to_fifo(s->fifo, buf);
- if (ret < 0)
- return ret;
-
- if (s->start_time != DBL_MAX && s->start_time != AV_NOPTS_VALUE) {
- double first_pts = s->start_time * AV_TIME_BASE;
- first_pts = FFMIN(FFMAX(first_pts, INT64_MIN), INT64_MAX);
- s->first_pts = av_rescale_q(first_pts, AV_TIME_BASE_Q,
- inlink->time_base);
- av_log(ctx, AV_LOG_VERBOSE, "Set first pts to (in:%"PRId64" out:%"PRId64")\n",
- s->first_pts, av_rescale_q(first_pts, AV_TIME_BASE_Q,
- outlink->time_base));
- } else {
- s->first_pts = buf->pts;
- }
+ av_assert1(s->frames_count == 2);
+
+ /* We haven't yet determined the pts of the first frame */
+ if (s->next_pts == AV_NOPTS_VALUE) {
+ if (s->frames[0]->pts != AV_NOPTS_VALUE) {
+ s->next_pts = s->frames[0]->pts;
+ av_log(ctx, AV_LOG_VERBOSE, "Set first pts to %"PRId64"\n",
+ s->next_pts);
} else {
av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
- "timestamp.\n");
- av_frame_free(&buf);
+ "timestamp.\n");
+ frame = shift_frame(s);
+ av_frame_free(&frame);
s->drop++;
+ return AVERROR(EAGAIN);
}
- return 0;
}
- /* now wait for the next timestamp */
- if (buf->pts == AV_NOPTS_VALUE || av_fifo_size(s->fifo) <= 0) {
- return write_to_fifo(s->fifo, buf);
+ /* If the second buffered frame is acceptable for the next frame, drop the first. */
+ if (s->frames[1]->pts <= s->next_pts) {
+ frame = shift_frame(s);
+ if (frame->pts == s->next_pts) {
+ av_log(ctx, AV_LOG_DEBUG, "Dropping frame with pts %"PRId64"\n", frame->pts);
+ s->drop++;
+ }
+ av_frame_free(&frame);
+ return AVERROR(EAGAIN);
+
+ /* The second buffered frame is in the future, output the first */
+ } else {
+ frame = av_frame_clone(s->frames[0]);
+ frame->pts = s->next_pts++;
+
+ /* If we're using a different pts than the frame's original, it's a dup */
+ if (s->frames[0]->pts != frame->pts) {
+ av_log(ctx, AV_LOG_DEBUG, "Duplicating frame with pts %"PRId64" to pts %"PRId64"\n",
+ s->frames[0]->pts, frame->pts);
+ dup = 1;
+ } else {
+ av_log(ctx, AV_LOG_DEBUG, "Writing frame with pts %"PRId64"\n", frame->pts);
+ }
+
+ ret = ff_filter_frame(outlink, frame);
+ if (ret >= 0) {
+ s->frames_out++;
+ s->dup += dup;
+ }
+
+ return ret;
}
+}
- /* number of output frames */
- delta = av_rescale_q_rnd(buf->pts - s->first_pts, inlink->time_base,
- outlink->time_base, s->rounding) - s->frames_out ;
+/* Write the last frame to the output */
+static int write_frame_eof(AVFilterContext *ctx, FPSContext *s, AVFilterLink *outlink)
+{
+ AVFrame *frame;
+ int ret;
+ int dup = 0;
- if (delta < 1) {
- /* drop everything buffered except the last */
- int drop = av_fifo_size(s->fifo)/sizeof(AVFrame*);
+ av_assert1(s->frames_count == 1);
- av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
- s->drop += drop;
+ /* Either we've already hit the status timestamp or it's in the past,
+ * e.g. AV_NOPTS_VALUE, so drop the last frame. */
+ if (s->status_pts <= s->next_pts) {
+ frame = shift_frame(s);
+ if (frame->pts == s->next_pts) {
+ av_log(ctx, AV_LOG_DEBUG, "Dropping frame with pts %"PRId64"\n", frame->pts);
+ s->drop++;
+ }
+ av_frame_free(&frame);
+ return AVERROR(EAGAIN);
+
+ /* We haven't yet reached the timestamp of the status (EOF) */
+ } else {
+ frame = av_frame_clone(s->frames[0]);
+ frame->pts = s->next_pts++;
+
+ /* If we're using a different pts than the frame's original, it's a dup */
+ if (s->frames[0]->pts != frame->pts) {
+ av_log(ctx, AV_LOG_DEBUG, "Duplicating frame with pts %"PRId64" to pts %"PRId64"\n",
+ s->frames[0]->pts, frame->pts);
+ dup = 1;
+ } else {
+ av_log(ctx, AV_LOG_DEBUG, "Writing frame with pts %"PRId64"\n", frame->pts);
+ }
- flush_fifo(s->fifo);
- ret = write_to_fifo(s->fifo, buf);
+ ret = ff_filter_frame(outlink, frame);
+ if (ret >= 0) {
+ s->frames_out++;
+ s->dup += dup;
+ }
return ret;
}
+}
- /* can output >= 1 frames */
- for (i = 0; i < delta; i++) {
- AVFrame *buf_out;
- av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
+static void update_eof_pts(AVFilterContext *ctx, FPSContext *s, AVFilterLink *inlink, AVFilterLink *outlink)
+{
+ /* Convert status_pts to outlink timebase */
+ int eof_rounding = (s->eof_action == EOF_ACTION_PASS) ? AV_ROUND_UP : s->rounding;
+ s->status_pts = av_rescale_q_rnd(s->status_pts, inlink->time_base,
+ outlink->time_base, eof_rounding);
- /* duplicate the frame if needed */
- if (!av_fifo_size(s->fifo) && i < delta - 1) {
- AVFrame *dup = av_frame_clone(buf_out);
+ av_log(ctx, AV_LOG_DEBUG, "EOF is at pts %"PRId64"\n", s->status_pts);
+}
- av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
- if (dup)
- ret = write_to_fifo(s->fifo, dup);
- else
- ret = AVERROR(ENOMEM);
+static int activate(AVFilterContext *ctx)
+{
+ FPSContext *s = ctx->priv;
+ AVFilterLink *inlink = ctx->inputs[0];
+ AVFilterLink *outlink = ctx->outputs[0];
- if (ret < 0) {
- av_frame_free(&buf_out);
- av_frame_free(&buf);
- return ret;
- }
+ int ret;
- s->dup++;
+ FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
+
+ /* No buffered status: normal operation */
+ if (!s->status) {
+
+ /* Read available input frames if we have room */
+ while (s->frames_count < 2 &&
+ ff_inlink_check_available_frame(inlink)) {
+ read_frame(ctx, s, inlink, outlink);
}
- buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
- outlink->time_base) + s->frames_out;
+ /* We do not yet have enough frames to produce output */
+ if (s->frames_count < 2) {
- if ((ret = ff_filter_frame(outlink, buf_out)) < 0) {
- av_frame_free(&buf);
- return ret;
+ ret = ff_inlink_acknowledge_status(inlink, &s->status, &s->status_pts);
+ if (!ret) {
+ /* If someone wants us to output, we'd better ask for more input */
+ if (ff_outlink_frame_wanted(outlink) > 0)
+ ff_inlink_request_frame(inlink);
+
+ return 0;
+ }
+ if (ret > 0) {
+ /* Need to calculate the end timestamp in the output timebase */
+ update_eof_pts(ctx, s, inlink, outlink);
+ }
}
- s->frames_out++;
+ /* Buffered frames are available, so generate an output frame */
+ if (s->frames_count == 2 && ff_outlink_frame_wanted(outlink) >= 0) {
+ ret = write_frame(ctx, s, outlink);
+ /* Couldn't generate a frame: e.g. a frame was dropped */
+ if (ret == AVERROR(EAGAIN)) {
+ /* Schedule us to perform another step */
+ ff_filter_set_ready(ctx, 100);
+ return 0;
+ }
+ return ret;
+ }
}
- flush_fifo(s->fifo);
- ret = write_to_fifo(s->fifo, buf);
+ /* There is a buffered status, flush frames and forward it */
+ if (s->status) {
+
+ /* There are still buffered frames, so flush a frame */
+ if (s->frames_count > 0) {
+ if (s->frames_count == 2)
+ ret = write_frame(ctx, s, outlink);
+ else
+ ret = write_frame_eof(ctx, s, outlink);
+
+ /* Couldn't generate a frame: e.g. a frame was dropped */
+ if (ret == AVERROR(EAGAIN)) {
+ /* Schedule us to perform another step */
+ ff_filter_set_ready(ctx, 100);
+ return 0;
+ }
+ }
+
+ /* No frames left, so forward the status */
+ if (s->frames_count == 0) {
+ ff_outlink_set_status(outlink, s->status, s->next_pts);
+ return 0;
+ }
+ }
- return ret;
+ return FFERROR_NOT_READY;
}
static const AVFilterPad avfilter_vf_fps_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
- .filter_frame = filter_frame,
},
{ NULL }
};
@@ -324,8 +386,7 @@ static const AVFilterPad avfilter_vf_fps_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
- .request_frame = request_frame,
- .config_props = config_props
+ .config_props = config_props,
},
{ NULL }
};
@@ -337,6 +398,7 @@ AVFilter ff_vf_fps = {
.uninit = uninit,
.priv_size = sizeof(FPSContext),
.priv_class = &fps_class,
+ .activate = activate,
.inputs = avfilter_vf_fps_inputs,
.outputs = avfilter_vf_fps_outputs,
};
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