[FFmpeg-devel] [PATCH 2/2] lavfi: make filter_frame non-recursive.

Nicolas George george at nsup.org
Sun Nov 13 12:10:21 EET 2016


A lot of changes happen at the same time:

- Add private_fields.h to devine private fields in AVFilterLink.
  It allows to have the private fields directly in structured types
  without needing an indirection for an opaque structure nor the
  structure definition in public headers.

- Add a framequeue fifo to AVFilterLink.

- split AVFilterLink.status into status_in and status_out: requires
  changes to the few filters and programs that use it directly
  (f_interleave, split, filtfmts).

- Add a field ready to AVFilterContext, marking when the filter is ready
  and its activation priority.

- Add flags to mark blocked links.

- Change ff_filter_frame() to enqueue the frame.

- Change all filtering functions to update the ready field and the
  blocked flags.

- Update ff_filter_graph_run_once() to use the ready field.

- buffersrc: always push the frame immediately.

Signed-off-by: Nicolas George <george at nsup.org>
---
 libavfilter/avfilter.c         | 458 ++++++++++++++++++++++++++++++++++-------
 libavfilter/avfilter.h         |  31 ++-
 libavfilter/avfiltergraph.c    |  51 ++---
 libavfilter/buffersink.c       |  19 +-
 libavfilter/buffersrc.c        |   6 +-
 libavfilter/f_interleave.c     |   5 +-
 libavfilter/internal.h         |   6 +
 libavfilter/private_fields.h   |  43 ++++
 libavfilter/split.c            |   3 +-
 libavfilter/tests/filtfmts.c   |   1 +
 libavfilter/vf_extractplanes.c |   3 +-
 tests/ref/fate/source          |   1 +
 12 files changed, 484 insertions(+), 143 deletions(-)
 create mode 100644 libavfilter/private_fields.h

diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
index 662f933..9df4a1c 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -34,6 +34,7 @@
 #include "libavutil/rational.h"
 #include "libavutil/samplefmt.h"
 
+#include "private_fields.h"
 #include "audio.h"
 #include "avfilter.h"
 #include "formats.h"
@@ -135,6 +136,10 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
 {
     AVFilterLink *link;
 
+    av_assert0(src->graph);
+    av_assert0(dst->graph);
+    av_assert0(src->graph == dst->graph);
+
     if (src->nb_outputs <= srcpad || dst->nb_inputs <= dstpad ||
         src->outputs[srcpad]      || dst->inputs[dstpad])
         return AVERROR(EINVAL);
@@ -147,6 +152,9 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
         return AVERROR(EINVAL);
     }
 
+#ifndef AVFILTER_LINK_INTERNAL_FIELDS
+# error AVFilterLink internal fields not defined
+#endif
     link = av_mallocz(sizeof(*link));
     if (!link)
         return AVERROR(ENOMEM);
@@ -160,6 +168,7 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
     link->type    = src->output_pads[srcpad].type;
     av_assert0(AV_PIX_FMT_NONE == -1 && AV_SAMPLE_FMT_NONE == -1);
     link->format  = -1;
+    ff_framequeue_init(&link->fifo, &src->graph->internal->frame_queues);
 
     return 0;
 }
@@ -170,6 +179,7 @@ void avfilter_link_free(AVFilterLink **link)
         return;
 
     av_frame_free(&(*link)->partial_buf);
+    ff_framequeue_free(&(*link)->fifo);
     ff_video_frame_pool_uninit((FFVideoFramePool**)&(*link)->video_frame_pool);
 
     av_freep(link);
@@ -180,16 +190,46 @@ int avfilter_link_get_channels(AVFilterLink *link)
     return link->channels;
 }
 
+static void ff_filter_set_ready(AVFilterContext *filter, unsigned priority)
+{
+    filter->ready = FFMAX(filter->ready, priority);
+}
+
+/**
+ * Clear frame_blocked_in on all outputs.
+ * This is necessary whenever something changes on input.
+ */
+static void filter_unblock(AVFilterContext *filter)
+{
+    unsigned i;
+
+    for (i = 0; i < filter->nb_outputs; i++)
+        filter->outputs[i]->frame_blocked_in = 0;
+}
+
+
 void ff_avfilter_link_set_in_status(AVFilterLink *link, int status, int64_t pts)
 {
-    ff_avfilter_link_set_out_status(link, status, pts);
+    if (link->status_in == status)
+        return;
+    av_assert0(!link->status_in);
+    link->status_in = status;
+    link->status_in_pts = pts;
+    link->frame_wanted_out = 0;
+    link->frame_blocked_in = 0;
+    filter_unblock(link->dst);
+    ff_filter_set_ready(link->dst, 200);
 }
 
 void ff_avfilter_link_set_out_status(AVFilterLink *link, int status, int64_t pts)
 {
-    link->status = status;
-    link->frame_wanted_in = link->frame_wanted_out = 0;
-    ff_update_link_current_pts(link, pts);
+    av_assert0(!link->frame_wanted_out);
+    av_assert0(!link->status_out);
+    link->status_out = status;
+    if (pts != AV_NOPTS_VALUE)
+        ff_update_link_current_pts(link, pts);
+    filter_unblock(link->dst);
+    ff_filter_set_ready(link->src, 200);
 }
 
 void avfilter_link_set_closed(AVFilterLink *link, int closed)
@@ -370,10 +410,23 @@ int ff_request_frame(AVFilterLink *link)
 {
     FF_TPRINTF_START(NULL, request_frame); ff_tlog_link(NULL, link, 1);
 
-    if (link->status)
-        return link->status;
-    link->frame_wanted_in = 1;
+    if (link->status_out)
+        return link->status_out;
+    if (link->status_in) {
+        if (ff_framequeue_queued_frames(&link->fifo)) {
+            av_assert1(!link->frame_wanted_out);
+            av_assert1(link->dst->ready >= 300);
+            return 0;
+        } else {
+            /* Acknowledge status change. Filters using ff_request_frame() will
+               handle the change automatically. Filters can also check the
+               status directly but none do yet. */
+            ff_avfilter_link_set_out_status(link, link->status_in, link->status_in_pts);
+            return link->status_out;
+        }
+    }
     link->frame_wanted_out = 1;
+    ff_filter_set_ready(link->src, 100);
     return 0;
 }
 
@@ -382,22 +435,17 @@ int ff_request_frame_to_filter(AVFilterLink *link)
     int ret = -1;
 
     FF_TPRINTF_START(NULL, request_frame_to_filter); ff_tlog_link(NULL, link, 1);
-    link->frame_wanted_in = 0;
+    /* Assume the filter is blocked, let the method clear it if not */
+    link->frame_blocked_in = 1;
     if (link->srcpad->request_frame)
         ret = link->srcpad->request_frame(link);
     else if (link->src->inputs[0])
         ret = ff_request_frame(link->src->inputs[0]);
-    if (ret == AVERROR_EOF && link->partial_buf) {
-        AVFrame *pbuf = link->partial_buf;
-        link->partial_buf = NULL;
-        ret = ff_filter_frame_framed(link, pbuf);
-        ff_avfilter_link_set_in_status(link, AVERROR_EOF, AV_NOPTS_VALUE);
-        link->frame_wanted_out = 0;
-        return ret;
-    }
     if (ret < 0) {
-        if (ret != AVERROR(EAGAIN) && ret != link->status)
+        if (ret != AVERROR(EAGAIN) && ret != link->status_in)
             ff_avfilter_link_set_in_status(link, ret, AV_NOPTS_VALUE);
+        if (ret == AVERROR_EOF)
+            ret = 0;
     }
     return ret;
 }
@@ -1056,11 +1104,6 @@ static int ff_filter_frame_framed(AVFilterLink *link, AVFrame *frame)
     AVFilterCommand *cmd= link->dst->command_queue;
     int64_t pts;
 
-    if (link->status) {
-        av_frame_free(&frame);
-        return link->status;
-    }
-
     if (!(filter_frame = dst->filter_frame))
         filter_frame = default_filter_frame;
 
@@ -1142,52 +1185,9 @@ fail:
     return ret;
 }
 
-static int ff_filter_frame_needs_framing(AVFilterLink *link, AVFrame *frame)
-{
-    int insamples = frame->nb_samples, inpos = 0, nb_samples;
-    AVFrame *pbuf = link->partial_buf;
-    int nb_channels = av_frame_get_channels(frame);
-    int ret = 0;
-
-    /* Handle framing (min_samples, max_samples) */
-    while (insamples) {
-        if (!pbuf) {
-            AVRational samples_tb = { 1, link->sample_rate };
-            pbuf = ff_get_audio_buffer(link, link->partial_buf_size);
-            if (!pbuf) {
-                av_log(link->dst, AV_LOG_WARNING,
-                       "Samples dropped due to memory allocation failure.\n");
-                return 0;
-            }
-            av_frame_copy_props(pbuf, frame);
-            pbuf->pts = frame->pts;
-            if (pbuf->pts != AV_NOPTS_VALUE)
-                pbuf->pts += av_rescale_q(inpos, samples_tb, link->time_base);
-            pbuf->nb_samples = 0;
-        }
-        nb_samples = FFMIN(insamples,
-                           link->partial_buf_size - pbuf->nb_samples);
-        av_samples_copy(pbuf->extended_data, frame->extended_data,
-                        pbuf->nb_samples, inpos,
-                        nb_samples, nb_channels, link->format);
-        inpos                   += nb_samples;
-        insamples               -= nb_samples;
-        pbuf->nb_samples += nb_samples;
-        if (pbuf->nb_samples >= link->min_samples) {
-            ret = ff_filter_frame_framed(link, pbuf);
-            pbuf = NULL;
-        } else {
-            if (link->frame_wanted_out)
-                link->frame_wanted_in = 1;
-        }
-    }
-    av_frame_free(&frame);
-    link->partial_buf = pbuf;
-    return ret;
-}
-
 int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
 {
+    int ret;
     FF_TPRINTF_START(NULL, filter_frame); ff_tlog_link(NULL, link, 1); ff_tlog(NULL, " "); ff_tlog_ref(NULL, frame, 1);
 
     /* Consistency checks */
@@ -1220,23 +1220,329 @@ int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
         }
     }
 
-    link->frame_wanted_out = 0;
+    link->frame_blocked_in = link->frame_wanted_out = 0;
     link->frame_count_in++;
-    /* Go directly to actual filtering if possible */
-    if (link->type == AVMEDIA_TYPE_AUDIO &&
-        link->min_samples &&
-        (link->partial_buf ||
-         frame->nb_samples < link->min_samples ||
-         frame->nb_samples > link->max_samples)) {
-        return ff_filter_frame_needs_framing(link, frame);
-    } else {
-        return ff_filter_frame_framed(link, frame);
+    filter_unblock(link->dst);
+    ret = ff_framequeue_add(&link->fifo, frame);
+    if (ret < 0) {
+        av_frame_free(&frame);
+        return ret;
     }
+    ff_filter_set_ready(link->dst, 300);
+    return 0;
+
 error:
     av_frame_free(&frame);
     return AVERROR_PATCHWELCOME;
 }
 
+static int samples_ready(AVFilterLink *link)
+{
+    return ff_framequeue_queued_frames(&link->fifo) &&
+           (ff_framequeue_queued_samples(&link->fifo) >= link->min_samples ||
+            link->status_in);
+}
+
+static int take_samples(AVFilterLink *link, unsigned min, unsigned max,
+                        AVFrame **rframe)
+{
+    AVFrame *frame0, *frame, *buf;
+    unsigned nb_samples, nb_frames, i, p;
+    int ret;
+
+    /* Note: this function relies on no format changes and must only be
+       called with enough samples. */
+    av_assert1(samples_ready(link));
+    frame0 = frame = ff_framequeue_peek(&link->fifo, 0);
+    if (frame->nb_samples >= min && frame->nb_samples < max) {
+        *rframe = ff_framequeue_take(&link->fifo);
+        return 0;
+    }
+    nb_frames = 0;
+    nb_samples = 0;
+    while (1) {
+        if (nb_samples + frame->nb_samples > max) {
+            if (nb_samples < min)
+                nb_samples = max;
+            break;
+        }
+        nb_samples += frame->nb_samples;
+        nb_frames++;
+        if (nb_frames == ff_framequeue_queued_frames(&link->fifo))
+            break;
+        frame = ff_framequeue_peek(&link->fifo, nb_frames);
+    }
+
+    buf = ff_get_audio_buffer(link, nb_samples);
+    if (!buf)
+        return AVERROR(ENOMEM);
+    ret = av_frame_copy_props(buf, frame0);
+    if (ret < 0) {
+        av_frame_free(&buf);
+        return ret;
+    }
+    buf->pts = frame0->pts;
+
+    p = 0;
+    for (i = 0; i < nb_frames; i++) {
+        frame = ff_framequeue_take(&link->fifo);
+        av_samples_copy(buf->extended_data, frame->extended_data, p, 0,
+                        frame->nb_samples, link->channels, link->format);
+        p += frame->nb_samples;
+    }
+    if (p < nb_samples) {
+        unsigned n = nb_samples - p;
+        frame = ff_framequeue_peek(&link->fifo, 0);
+        av_samples_copy(buf->extended_data, frame->extended_data, p, 0, n,
+                        link->channels, link->format);
+        frame->nb_samples -= n;
+        av_samples_copy(frame->extended_data, frame->extended_data, 0, n,
+                        frame->nb_samples, link->channels, link->format);
+        if (frame->pts != AV_NOPTS_VALUE)
+            frame->pts += av_rescale_q(n, av_make_q(1, link->sample_rate), link->time_base);
+        ff_framequeue_update_peeked(&link->fifo, 0);
+        ff_framequeue_skip_samples(&link->fifo, n);
+    }
+
+    *rframe = buf;
+    return 0;
+}
+
+int ff_filter_frame_to_filter(AVFilterLink *link)
+{
+    AVFrame *frame;
+    AVFilterContext *dst = link->dst;
+    int ret;
+
+    av_assert1(ff_framequeue_queued_frames(&link->fifo));
+    if (link->min_samples) {
+        int min = link->min_samples;
+        if (link->status_in)
+            min = FFMIN(min, ff_framequeue_queued_samples(&link->fifo));
+        ret = take_samples(link, min, link->max_samples, &frame);
+        if (ret < 0)
+            return ret;
+    } else {
+        frame = ff_framequeue_take(&link->fifo);
+    }
+    /* The filter will soon have received a new frame, that may allow it to
+       produce one or more: unblock its outputs. */
+    filter_unblock(dst);
+    ret = ff_filter_frame_framed(link, frame);
+    if (ret < 0 && ret != link->status_out) {
+        ff_avfilter_link_set_out_status(link, ret, AV_NOPTS_VALUE);
+    } else {
+        /* Run once again, to see if several frames were available, or if
+           the input status has also changed, or any other reason. */
+        ff_filter_set_ready(dst, 300);
+    }
+    return ret;
+}
+
+static int forward_status_change(AVFilterContext *filter, AVFilterLink *in)
+{
+    unsigned out = 0, progress = 0;
+    int ret;
+
+    av_assert0(!in->status_out);
+    if (!filter->nb_outputs) {
+        /* not necessary with the current API and sinks */
+        return 0;
+    }
+    while (!in->status_out) {
+        if (!filter->outputs[out]->status_in) {
+            progress++;
+            ret = ff_request_frame_to_filter(filter->outputs[out]);
+            if (ret < 0)
+                return ret;
+        }
+        if (++out == filter->nb_outputs) {
+            if (!progress) {
+                /* Every output already closed: input no longer interesting
+                   (example: overlay in shortest mode, other input closed). */
+                ff_avfilter_link_set_out_status(in, in->status_in, in->status_in_pts);
+                return 0;
+            }
+            progress = 0;
+            out = 0;
+        }
+    }
+    ff_filter_set_ready(filter, 200);
+    return 0;
+}
+
+#define FFERROR_NOT_READY FFERRTAG('N','R','D','Y')
+
+static int ff_filter_activate_default(AVFilterContext *filter)
+{
+    unsigned i;
+
+    for (i = 0; i < filter->nb_inputs; i++) {
+        if (samples_ready(filter->inputs[i])) {
+            return ff_filter_frame_to_filter(filter->inputs[i]);
+        }
+    }
+    for (i = 0; i < filter->nb_inputs; i++) {
+        if (filter->inputs[i]->status_in && !filter->inputs[i]->status_out) {
+            av_assert1(!ff_framequeue_queued_frames(&filter->inputs[i]->fifo));
+            return forward_status_change(filter, filter->inputs[i]);
+        }
+    }
+    for (i = 0; i < filter->nb_outputs; i++) {
+        if (filter->outputs[i]->frame_wanted_out &&
+            !filter->outputs[i]->frame_blocked_in) {
+            return ff_request_frame_to_filter(filter->outputs[i]);
+        }
+    }
+    return FFERROR_NOT_READY;
+}
+
+/*
+   Filter scheduling and activation
+
+   When a filter is activated, it must:
+   - if possible, output a frame;
+   - else, if relevant, forward the input status change;
+   - else, check outputs for wanted frames and forward the requests.
+
+   The following AVFilterLink fields are used for activation:
+
+   - frame_wanted_out:
+
+     This field indicates if a frame is needed on this input of the
+     destination filter. A positive value indicates that a frame is needed
+     to process queued frames or internal data or to satisfy the
+     application; a zero value indicates that a frame is not especially
+     needed but could be processed anyway; a negative value indicates that a
+     frame would just be queued.
+
+     It is set by filters using ff_request_frame() or ff_request_no_frame(),
+     when requested by the application through a specific API or when it is
+     set on one of the outputs.
+
+     It is cleared when a frame is sent from the source using
+     ff_filter_frame().
+
+     It is also cleared when a status change is sent from the source using
+     ff_avfilter_link_set_in_status().
+
+   - frame_blocked_in:
+
+     This field means that the source filter can not generate a frame as is.
+     Its goal is to avoid repeatedly calling the request_frame() method on
+     the same link.
+
+     It is set by the framework on all outputs of a filter before activating it.
+
+     It is automatically cleared by ff_filter_frame().
+
+     It is also automatically cleared by ff_avfilter_link_set_in_status().
+
+     It is also cleared on all outputs (using filter_unblock()) when
+     something happens on an input: processing a frame or changing the
+     status.
+
+   - fifo:
+
+     Contains the frames queued on a filter input. If it contains frames and
+     frame_wanted_out is not set, then the filter can be activated. If that
+     result in the filter not able to use these frames, the filter must set
+     frame_wanted_out to ask for more frames.
+
+   - status_in and status_in_pts:
+
+     Status (EOF or error code) of the link and timestamp of the status
+     change (in link time base, same as frames) as seen from the input of
+     the link. The status change is considered happening after the frames
+     queued in fifo.
+
+     It is set by the source filter using ff_avfilter_link_set_in_status().
+
+   - status_out:
+
+     Status of the link as seen from the output of the link. The status
+     change is considered having already happened.
+
+     It is set by the destination filter using
+     ff_avfilter_link_set_out_status().
+
+   Filters are activated according to the ready field, set using the
+   ff_filter_set_ready(). Eventually, a priority queue will be used.
+   ff_filter_set_ready() is called whenever anything could cause progress to
+   be possible. Marking a filter ready when it is not is not a problem,
+   except for the small overhead it causes.
+
+   Conditions that cause a filter to be marked ready are:
+
+   - frames added on an input link;
+
+   - changes in the input or output status of an input link;
+
+   - requests for a frame on an output link;
+
+   - after any actual processing using the legacy methods (filter_frame(),
+     and request_frame() to acknowledge status changes), to run once more
+     and check if enough input was present for several frames.
+
+   Exemples of scenarios to consider:
+
+   - buffersrc: activate if frame_wanted_out to notify the application;
+     activate when the application adds a frame to push it immediately.
+
+   - testsrc: activate only if frame_wanted_out to produce and push a frame.
+
+   - concat (not at stitch points): can process a frame on any output.
+     Activate if frame_wanted_out on output to forward on the corresponding
+     input. Activate when a frame is present on input to process it
+     immediately.
+
+   - framesync: needs at least one frame on each input; extra frames on the
+     wrong input will accumulate. When a frame is first added on one input,
+     set frame_wanted_out<0 on it to avoid getting more (would trigger
+     testsrc) and frame_wanted_out>0 on the other to allow processing it.
+
+   Activation of old filters:
+
+   In order to activate a filter implementing the legacy filter_frame() and
+   request_frame() methods, perform the first possible of the following
+   actions:
+
+   - If an input has frames in fifo and frame_wanted_out == 0, dequeue a
+     frame and call filter_frame().
+
+     Ratinale: filter frames as soon as possible instead of leaving them
+     queued; frame_wanted_out < 0 is not possible since the old API does not
+     set it nor provides any similar feedback; frame_wanted_out > 0 happens
+     when min_samples > 0 and there are not enough samples queued.
+
+   - If an input has status_in set but not status_out, try to call
+     request_frame() on one of the outputs in the hope that it will trigger
+     request_frame() on the input with status_in and acknowledge it. This is
+     awkward and fragile, filters with several inputs or outputs should be
+     updated to direct activation as soon as possible.
+
+   - If an output has frame_wanted_out > 0 and not frame_blocked_in, call
+     request_frame().
+
+     Rationale: checking frame_blocked_in is necessary to avoid requesting
+     repeatedly on a blocked input if another is not blocked (example:
+     [buffersrc1][testsrc1][buffersrc2][testsrc2]concat=v=2).
+
+     TODO: respect needs_fifo and remove auto-inserted fifos.
+
+ */
+
+int ff_filter_activate(AVFilterContext *filter)
+{
+    int ret;
+
+    filter->ready = 0;
+    ret = ff_filter_activate_default(filter);
+    if (ret == FFERROR_NOT_READY)
+        ret = 0;
+    return ret;
+}
+
 const AVClass *avfilter_get_class(void)
 {
     return &avfilter_class;
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index d21b144..3629d5b 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -368,6 +368,13 @@ struct AVFilterContext {
      * Overrides global number of threads set per filter graph.
      */
     int nb_threads;
+
+    /**
+     * Ready status of the filter.
+     * A non-0 value means that the filter needs activating;
+     * a higher value suggests a more urgent activation.
+     */
+    unsigned ready;
 };
 
 /**
@@ -509,18 +516,6 @@ struct AVFilterLink {
     int max_samples;
 
     /**
-     * Link status.
-     * If not zero, all attempts of filter_frame or request_frame
-     * will fail with the corresponding code, and if necessary the reference
-     * will be destroyed.
-     * If request_frame returns an error, the status is set on the
-     * corresponding link.
-     * It can be set also be set by either the source or the destination
-     * filter.
-     */
-    int status;
-
-    /**
      * Number of channels.
      */
     int channels;
@@ -541,13 +536,6 @@ struct AVFilterLink {
     void *video_frame_pool;
 
     /**
-     * True if a frame is currently wanted on the input of this filter.
-     * Set when ff_request_frame() is called by the output,
-     * cleared when the request is handled or forwarded.
-     */
-    int frame_wanted_in;
-
-    /**
      * True if a frame is currently wanted on the output of this filter.
      * Set when ff_request_frame() is called by the output,
      * cleared when a frame is filtered.
@@ -559,6 +547,11 @@ struct AVFilterLink {
      * AVHWFramesContext describing the frames.
      */
     AVBufferRef *hw_frames_ctx;
+
+#ifdef AVFILTER_LINK_INTERNAL_FIELDS
+    AVFILTER_LINK_INTERNAL_FIELDS
+#endif
+
 };
 
 /**
diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 3af698d..0a6431f 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -32,6 +32,7 @@
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 
+#include "private_fields.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
@@ -87,6 +88,7 @@ AVFilterGraph *avfilter_graph_alloc(void)
 
     ret->av_class = &filtergraph_class;
     av_opt_set_defaults(ret);
+    ff_framequeue_global_init(&ret->internal->frame_queues);
 
     return ret;
 }
@@ -1377,10 +1379,10 @@ void ff_avfilter_graph_update_heap(AVFilterGraph *graph, AVFilterLink *link)
     heap_bubble_down(graph, link, link->age_index);
 }
 
-
 int avfilter_graph_request_oldest(AVFilterGraph *graph)
 {
     AVFilterLink *oldest = graph->sink_links[0];
+    int64_t frame_count;
     int r;
 
     while (graph->sink_links_count) {
@@ -1400,7 +1402,8 @@ int avfilter_graph_request_oldest(AVFilterGraph *graph)
     if (!graph->sink_links_count)
         return AVERROR_EOF;
     av_assert1(oldest->age_index >= 0);
-    while (oldest->frame_wanted_out) {
+    frame_count = oldest->frame_count_out;
+    while (frame_count == oldest->frame_count_out) {
         r = ff_filter_graph_run_once(graph);
         if (r < 0)
             return r;
@@ -1408,41 +1411,17 @@ int avfilter_graph_request_oldest(AVFilterGraph *graph)
     return 0;
 }
 
-static AVFilterLink *graph_run_once_find_filter(AVFilterGraph *graph)
-{
-    unsigned i, j;
-    AVFilterContext *f;
-
-    /* TODO: replace scanning the graph with a priority list */
-    for (i = 0; i < graph->nb_filters; i++) {
-        f = graph->filters[i];
-        for (j = 0; j < f->nb_outputs; j++)
-            if (f->outputs[j]->frame_wanted_in)
-                return f->outputs[j];
-    }
-    for (i = 0; i < graph->nb_filters; i++) {
-        f = graph->filters[i];
-        for (j = 0; j < f->nb_outputs; j++)
-            if (f->outputs[j]->frame_wanted_out)
-                return f->outputs[j];
-    }
-    return NULL;
-}
-
 int ff_filter_graph_run_once(AVFilterGraph *graph)
 {
-    AVFilterLink *link;
-    int ret;
-
-    link = graph_run_once_find_filter(graph);
-    if (!link) {
-        av_log(NULL, AV_LOG_WARNING, "Useless run of a filter graph\n");
+    AVFilterContext *filter;
+    unsigned i;
+
+    av_assert0(graph->nb_filters);
+    filter = graph->filters[0];
+    for (i = 1; i < graph->nb_filters; i++)
+        if (graph->filters[i]->ready > filter->ready)
+            filter = graph->filters[i];
+    if (!filter->ready)
         return AVERROR(EAGAIN);
-    }
-    ret = ff_request_frame_to_filter(link);
-    if (ret == AVERROR_EOF)
-        /* local EOF will be forwarded through request_frame() /
-           set_status() until it reaches the sink */
-        ret = 0;
-    return ret < 0 ? ret : 1;
+    return ff_filter_activate(filter);
 }
diff --git a/libavfilter/buffersink.c b/libavfilter/buffersink.c
index 2feb56d..e0af091 100644
--- a/libavfilter/buffersink.c
+++ b/libavfilter/buffersink.c
@@ -31,6 +31,7 @@
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 
+#include "private_fields.h"
 #include "audio.h"
 #include "avfilter.h"
 #include "buffersink.h"
@@ -129,18 +130,26 @@ int attribute_align_arg av_buffersink_get_frame_flags(AVFilterContext *ctx, AVFr
 {
     BufferSinkContext *buf = ctx->priv;
     AVFilterLink *inlink = ctx->inputs[0];
-    int ret;
+    int peek_in_framequeue = 0, ret;
+    int64_t frame_count;
     AVFrame *cur_frame;
 
     /* no picref available, fetch it from the filterchain */
     while (!av_fifo_size(buf->fifo)) {
-        if (inlink->status)
-            return inlink->status;
-        if (flags & AV_BUFFERSINK_FLAG_NO_REQUEST)
+        /* if peek_in_framequeue is true later, then ff_request_frame() and
+           the ff_filter_graph_run_once() loop will take a frame from it and
+           move it to the internal fifo, ending the global loop */
+        av_assert0(!peek_in_framequeue);
+        if (inlink->status_out)
+            return inlink->status_out;
+        peek_in_framequeue = ff_framequeue_queued_frames(&inlink->fifo) &&
+                             ff_framequeue_queued_samples(&inlink->fifo) >= inlink->min_samples;
+        if ((flags & AV_BUFFERSINK_FLAG_NO_REQUEST) && !peek_in_framequeue)
             return AVERROR(EAGAIN);
         if ((ret = ff_request_frame(inlink)) < 0)
             return ret;
-        while (inlink->frame_wanted_out) {
+        frame_count = inlink->frame_count_out;
+        while (frame_count == inlink->frame_count_out) {
             ret = ff_filter_graph_run_once(ctx->graph);
             if (ret < 0)
                 return ret;
diff --git a/libavfilter/buffersrc.c b/libavfilter/buffersrc.c
index 9294811..1314397 100644
--- a/libavfilter/buffersrc.c
+++ b/libavfilter/buffersrc.c
@@ -184,6 +184,7 @@ static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
 
     if (!frame) {
         s->eof = 1;
+        ff_avfilter_link_set_in_status(ctx->outputs[0], AVERROR_EOF, AV_NOPTS_VALUE);
         return 0;
     } else if (s->eof)
         return AVERROR(EINVAL);
@@ -235,9 +236,8 @@ static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
         return ret;
     }
 
-    if ((flags & AV_BUFFERSRC_FLAG_PUSH))
-        if ((ret = ctx->output_pads[0].request_frame(ctx->outputs[0])) < 0)
-            return ret;
+    if ((ret = ctx->output_pads[0].request_frame(ctx->outputs[0])) < 0)
+        return ret;
 
     return 0;
 }
diff --git a/libavfilter/f_interleave.c b/libavfilter/f_interleave.c
index 422f2bf..44ee11b 100644
--- a/libavfilter/f_interleave.c
+++ b/libavfilter/f_interleave.c
@@ -26,6 +26,7 @@
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/opt.h"
+#include "private_fields.h"
 #include "avfilter.h"
 #include "bufferqueue.h"
 #include "formats.h"
@@ -59,7 +60,7 @@ inline static int push_frame(AVFilterContext *ctx)
     for (i = 0; i < ctx->nb_inputs; i++) {
         struct FFBufQueue *q = &s->queues[i];
 
-        if (!q->available && !ctx->inputs[i]->status)
+        if (!q->available && !ctx->inputs[i]->status_out)
             return 0;
         if (q->available) {
             frame = ff_bufqueue_peek(q, 0);
@@ -190,7 +191,7 @@ static int request_frame(AVFilterLink *outlink)
     int i, ret;
 
     for (i = 0; i < ctx->nb_inputs; i++) {
-        if (!s->queues[i].available && !ctx->inputs[i]->status) {
+        if (!s->queues[i].available && !ctx->inputs[i]->status_out) {
             ret = ff_request_frame(ctx->inputs[i]);
             if (ret != AVERROR_EOF)
                 return ret;
diff --git a/libavfilter/internal.h b/libavfilter/internal.h
index 3856012..a8b69fd 100644
--- a/libavfilter/internal.h
+++ b/libavfilter/internal.h
@@ -29,6 +29,7 @@
 #include "avfiltergraph.h"
 #include "formats.h"
 #include "framepool.h"
+#include "framequeue.h"
 #include "thread.h"
 #include "version.h"
 #include "video.h"
@@ -147,6 +148,7 @@ struct AVFilterPad {
 struct AVFilterGraphInternal {
     void *thread;
     avfilter_execute_func *thread_execute;
+    FFFrameQueueGlobal frame_queues;
 };
 
 struct AVFilterInternal {
@@ -336,6 +338,8 @@ int ff_request_frame(AVFilterLink *link);
 
 int ff_request_frame_to_filter(AVFilterLink *link);
 
+int ff_filter_frame_to_filter(AVFilterLink *link);
+
 #define AVFILTER_DEFINE_CLASS(fname)            \
     static const AVClass fname##_class = {      \
         .class_name = #fname,                   \
@@ -376,6 +380,8 @@ int ff_filter_frame(AVFilterLink *link, AVFrame *frame);
  */
 AVFilterContext *ff_filter_alloc(const AVFilter *filter, const char *inst_name);
 
+int ff_filter_activate(AVFilterContext *filter);
+
 /**
  * Remove a filter from a graph;
  */
diff --git a/libavfilter/private_fields.h b/libavfilter/private_fields.h
new file mode 100644
index 0000000..5a3df68
--- /dev/null
+++ b/libavfilter/private_fields.h
@@ -0,0 +1,43 @@
+/*
+ * Generic frame queue
+ * Copyright (c) 2016 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 "framequeue.h"
+
+#define AVFILTER_LINK_INTERNAL_FIELDS \
+\
+    FFFrameQueue fifo; \
+\
+    int frame_blocked_in; \
+\
+    /** \
+     * Link input status. \
+     */ \
+    int status_in; \
+    int64_t status_in_pts; \
+\
+    /** \
+     * Link output status. \
+     * If not zero, all attempts of request_frame will fail with the \
+     * corresponding code.
+     */ \
+    int status_out; \
+ \
+/* define AVFILTER_LINK_INTERNAL_FIELDS */
diff --git a/libavfilter/split.c b/libavfilter/split.c
index 6cf4ab1..89e3604 100644
--- a/libavfilter/split.c
+++ b/libavfilter/split.c
@@ -30,6 +30,7 @@
 #include "libavutil/mem.h"
 #include "libavutil/opt.h"
 
+#include "private_fields.h"
 #include "avfilter.h"
 #include "audio.h"
 #include "formats.h"
@@ -78,7 +79,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
     for (i = 0; i < ctx->nb_outputs; i++) {
         AVFrame *buf_out;
 
-        if (ctx->outputs[i]->status)
+        if (ctx->outputs[i]->status_in)
             continue;
         buf_out = av_frame_clone(frame);
         if (!buf_out) {
diff --git a/libavfilter/tests/filtfmts.c b/libavfilter/tests/filtfmts.c
index 46a2d94..682af8c 100644
--- a/libavfilter/tests/filtfmts.c
+++ b/libavfilter/tests/filtfmts.c
@@ -25,6 +25,7 @@
 #include "libavutil/pixdesc.h"
 #include "libavutil/samplefmt.h"
 
+#include "libavfilter/private_fields.h"
 #include "libavfilter/avfilter.h"
 #include "libavfilter/formats.h"
 
diff --git a/libavfilter/vf_extractplanes.c b/libavfilter/vf_extractplanes.c
index a23f838..c4b01e0 100644
--- a/libavfilter/vf_extractplanes.c
+++ b/libavfilter/vf_extractplanes.c
@@ -22,6 +22,7 @@
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
+#include "private_fields.h"
 #include "avfilter.h"
 #include "drawutils.h"
 #include "internal.h"
@@ -245,7 +246,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
         const int idx = s->map[i];
         AVFrame *out;
 
-        if (outlink->status)
+        if (outlink->status_in)
             continue;
 
         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
diff --git a/tests/ref/fate/source b/tests/ref/fate/source
index 4ee8a58..23ffd8a 100644
--- a/tests/ref/fate/source
+++ b/tests/ref/fate/source
@@ -29,3 +29,4 @@ compat/cuda/nvcuvid.h
 compat/float/float.h
 compat/float/limits.h
 compat/nvenc/nvEncodeAPI.h
+libavfilter/private_fields.h
-- 
2.10.2



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