lavfi: get rid of FF_INTERNAL_FIELDS

This hack is used to limit the visibility of some AVFilterLink fields to only certain files. Replace it with the same pattern that is used e.g. in lavf AVStream/FFStream and avoid exposing these internal fields in a public header completely.
2022-10-25 15:36:36 +02:00
parent 1e7d2007c3
commit 86417b759f
6 changed files with 198 additions and 136 deletions
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -34,15 +34,14 @@
 #include "libavutil/rational.h"
 #include "libavutil/samplefmt.h"

-#define FF_INTERNAL_FIELDS 1
-#include "framequeue.h"
-
 #include "audio.h"
 #include "avfilter.h"
 #include "filters.h"
 #include "formats.h"
+#include "framequeue.h"
 #include "framepool.h"
 #include "internal.h"
+#include "link_internal.h"
 #include "video.h"

 static void tlog_ref(void *ctx, AVFrame *ref, int end)
@@ -149,6 +148,7 @@ int ff_append_outpad_free_name(AVFilterContext *f, AVFilterPad *p)
 int avfilter_link(AVFilterContext *src, unsigned srcpad,
                  AVFilterContext *dst, unsigned dstpad)
 {
+    FilterLinkInternal *li;
    AVFilterLink *link;

    av_assert0(src->graph);
@@ -172,9 +172,10 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
        return AVERROR(EINVAL);
    }

-    link = av_mallocz(sizeof(*link));
-    if (!link)
+    li = av_mallocz(sizeof(*li));
+    if (!li)
        return AVERROR(ENOMEM);
+    link = &li->l;

    src->outputs[srcpad] = dst->inputs[dstpad] = link;

@@ -186,17 +187,20 @@ int avfilter_link(AVFilterContext *src, unsigned srcpad,
    av_assert0(AV_PIX_FMT_NONE == -1 && AV_SAMPLE_FMT_NONE == -1);
    link->format  = -1;
    link->colorspace = AVCOL_SPC_UNSPECIFIED;
-    ff_framequeue_init(&link->fifo, &src->graph->internal->frame_queues);
+    ff_framequeue_init(&li->fifo, &src->graph->internal->frame_queues);

    return 0;
 }

 void avfilter_link_free(AVFilterLink **link)
 {
+    FilterLinkInternal *li;
+
    if (!*link)
        return;
+    li = ff_link_internal(*link);

-    ff_framequeue_free(&(*link)->fifo);
+    ff_framequeue_free(&li->fifo);
    ff_frame_pool_uninit((FFFramePool**)&(*link)->frame_pool);
    av_channel_layout_uninit(&(*link)->ch_layout);

@@ -227,20 +231,24 @@ static void filter_unblock(AVFilterContext *filter)
 {
    unsigned i;

-    for (i = 0; i < filter->nb_outputs; i++)
-        filter->outputs[i]->frame_blocked_in = 0;
+    for (i = 0; i < filter->nb_outputs; i++) {
+        FilterLinkInternal * const li = ff_link_internal(filter->outputs[i]);
+        li->frame_blocked_in = 0;
+    }
 }


 void ff_avfilter_link_set_in_status(AVFilterLink *link, int status, int64_t pts)
 {
-    if (link->status_in == status)
+    FilterLinkInternal * const li = ff_link_internal(link);
+
+    if (li->status_in == status)
        return;
-    av_assert0(!link->status_in);
-    link->status_in = status;
-    link->status_in_pts = pts;
+    av_assert0(!li->status_in);
+    li->status_in = status;
+    li->status_in_pts = pts;
    link->frame_wanted_out = 0;
-    link->frame_blocked_in = 0;
+    li->frame_blocked_in = 0;
    filter_unblock(link->dst);
    ff_filter_set_ready(link->dst, 200);
 }
@@ -251,9 +259,11 @@ void ff_avfilter_link_set_in_status(AVFilterLink *link, int status, int64_t pts)
 */
 static void link_set_out_status(AVFilterLink *link, int status, int64_t pts)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
+
    av_assert0(!link->frame_wanted_out);
-    av_assert0(!link->status_out);
-    link->status_out = status;
+    av_assert0(!li->status_out);
+    li->status_out = status;
    if (pts != AV_NOPTS_VALUE)
        update_link_current_pts(link, pts);
    filter_unblock(link->dst);
@@ -437,13 +447,15 @@ void ff_tlog_link(void *ctx, AVFilterLink *link, int end)

 int ff_request_frame(AVFilterLink *link)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
+
    FF_TPRINTF_START(NULL, request_frame); ff_tlog_link(NULL, link, 1);

    av_assert1(!link->dst->filter->activate);
-    if (link->status_out)
-        return link->status_out;
-    if (link->status_in) {
-        if (ff_framequeue_queued_frames(&link->fifo)) {
+    if (li->status_out)
+        return li->status_out;
+    if (li->status_in) {
+        if (ff_framequeue_queued_frames(&li->fifo)) {
            av_assert1(!link->frame_wanted_out);
            av_assert1(link->dst->ready >= 300);
            return 0;
@@ -451,8 +463,8 @@ int ff_request_frame(AVFilterLink *link)
            /* Acknowledge status change. Filters using ff_request_frame() will
               handle the change automatically. Filters can also check the
               status directly but none do yet. */
-            link_set_out_status(link, link->status_in, link->status_in_pts);
-            return link->status_out;
+            link_set_out_status(link, li->status_in, li->status_in_pts);
+            return li->status_out;
        }
    }
    link->frame_wanted_out = 1;
@@ -465,14 +477,18 @@ static int64_t guess_status_pts(AVFilterContext *ctx, int status, AVRational lin
    unsigned i;
    int64_t r = INT64_MAX;

-    for (i = 0; i < ctx->nb_inputs; i++)
-        if (ctx->inputs[i]->status_out == status)
+    for (i = 0; i < ctx->nb_inputs; i++) {
+        FilterLinkInternal * const li = ff_link_internal(ctx->inputs[i]);
+        if (li->status_out == status)
            r = FFMIN(r, av_rescale_q(ctx->inputs[i]->current_pts, ctx->inputs[i]->time_base, link_time_base));
+    }
    if (r < INT64_MAX)
        return r;
    av_log(ctx, AV_LOG_WARNING, "EOF timestamp not reliable\n");
-    for (i = 0; i < ctx->nb_inputs; i++)
-        r = FFMIN(r, av_rescale_q(ctx->inputs[i]->status_in_pts, ctx->inputs[i]->time_base, link_time_base));
+    for (i = 0; i < ctx->nb_inputs; i++) {
+        FilterLinkInternal * const li = ff_link_internal(ctx->inputs[i]);
+        r = FFMIN(r, av_rescale_q(li->status_in_pts, ctx->inputs[i]->time_base, link_time_base));
+    }
    if (r < INT64_MAX)
        return r;
    return AV_NOPTS_VALUE;
@@ -480,17 +496,18 @@ static int64_t guess_status_pts(AVFilterContext *ctx, int status, AVRational lin

 static int ff_request_frame_to_filter(AVFilterLink *link)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
    int ret = -1;

    FF_TPRINTF_START(NULL, request_frame_to_filter); ff_tlog_link(NULL, link, 1);
    /* Assume the filter is blocked, let the method clear it if not */
-    link->frame_blocked_in = 1;
+    li->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 < 0) {
-        if (ret != AVERROR(EAGAIN) && ret != link->status_in)
+        if (ret != AVERROR(EAGAIN) && ret != li->status_in)
            ff_avfilter_link_set_in_status(link, ret, guess_status_pts(link->src, ret, link->time_base));
        if (ret == AVERROR_EOF)
            ret = 0;
@@ -988,6 +1005,7 @@ fail:

 int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
    int ret;
    FF_TPRINTF_START(NULL, filter_frame); ff_tlog_link(NULL, link, 1); ff_tlog(NULL, " "); tlog_ref(NULL, frame, 1);

@@ -1027,11 +1045,11 @@ FF_ENABLE_DEPRECATION_WARNINGS
 #endif
    }

-    link->frame_blocked_in = link->frame_wanted_out = 0;
+    li->frame_blocked_in = link->frame_wanted_out = 0;
    link->frame_count_in++;
    link->sample_count_in += frame->nb_samples;
    filter_unblock(link->dst);
-    ret = ff_framequeue_add(&link->fifo, frame);
+    ret = ff_framequeue_add(&li->fifo, frame);
    if (ret < 0) {
        av_frame_free(&frame);
        return ret;
@@ -1044,16 +1062,17 @@ error:
    return AVERROR_PATCHWELCOME;
 }

-static int samples_ready(AVFilterLink *link, unsigned min)
+static int samples_ready(FilterLinkInternal *link, unsigned min)
 {
    return ff_framequeue_queued_frames(&link->fifo) &&
           (ff_framequeue_queued_samples(&link->fifo) >= min ||
            link->status_in);
 }

-static int take_samples(AVFilterLink *link, unsigned min, unsigned max,
+static int take_samples(FilterLinkInternal *li, unsigned min, unsigned max,
                        AVFrame **rframe)
 {
+    AVFilterLink *link = &li->l;
    AVFrame *frame0, *frame, *buf;
    unsigned nb_samples, nb_frames, i, p;
    int ret;
@@ -1061,9 +1080,9 @@ static int take_samples(AVFilterLink *link, unsigned min, unsigned max,
    /* Note: this function relies on no format changes and must only be
       called with enough samples. */
    av_assert1(samples_ready(link, link->min_samples));
-    frame0 = frame = ff_framequeue_peek(&link->fifo, 0);
-    if (!link->fifo.samples_skipped && frame->nb_samples >= min && frame->nb_samples <= max) {
-        *rframe = ff_framequeue_take(&link->fifo);
+    frame0 = frame = ff_framequeue_peek(&li->fifo, 0);
+    if (!li->fifo.samples_skipped && frame->nb_samples >= min && frame->nb_samples <= max) {
+        *rframe = ff_framequeue_take(&li->fifo);
        return 0;
    }
    nb_frames = 0;
@@ -1076,9 +1095,9 @@ static int take_samples(AVFilterLink *link, unsigned min, unsigned max,
        }
        nb_samples += frame->nb_samples;
        nb_frames++;
-        if (nb_frames == ff_framequeue_queued_frames(&link->fifo))
+        if (nb_frames == ff_framequeue_queued_frames(&li->fifo))
            break;
-        frame = ff_framequeue_peek(&link->fifo, nb_frames);
+        frame = ff_framequeue_peek(&li->fifo, nb_frames);
    }

    buf = ff_get_audio_buffer(link, nb_samples);
@@ -1092,7 +1111,7 @@ static int take_samples(AVFilterLink *link, unsigned min, unsigned max,

    p = 0;
    for (i = 0; i < nb_frames; i++) {
-        frame = ff_framequeue_take(&link->fifo);
+        frame = ff_framequeue_take(&li->fifo);
        av_samples_copy(buf->extended_data, frame->extended_data, p, 0,
                        frame->nb_samples, link->ch_layout.nb_channels, link->format);
        p += frame->nb_samples;
@@ -1100,10 +1119,10 @@ static int take_samples(AVFilterLink *link, unsigned min, unsigned max,
    }
    if (p < nb_samples) {
        unsigned n = nb_samples - p;
-        frame = ff_framequeue_peek(&link->fifo, 0);
+        frame = ff_framequeue_peek(&li->fifo, 0);
        av_samples_copy(buf->extended_data, frame->extended_data, p, 0, n,
                        link->ch_layout.nb_channels, link->format);
-        ff_framequeue_skip_samples(&link->fifo, n, link->time_base);
+        ff_framequeue_skip_samples(&li->fifo, n, link->time_base);
    }

    *rframe = buf;
@@ -1112,6 +1131,7 @@ static int take_samples(AVFilterLink *link, unsigned min, unsigned max,

 static int ff_filter_frame_to_filter(AVFilterLink *link)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
    AVFrame *frame = NULL;
    AVFilterContext *dst = link->dst;
    int ret;
@@ -1132,7 +1152,7 @@ static int ff_filter_frame_to_filter(AVFilterLink *link)
       before the frame; ff_filter_frame_framed() will re-increment it. */
    link->frame_count_out--;
    ret = ff_filter_frame_framed(link, frame);
-    if (ret < 0 && ret != link->status_out) {
+    if (ret < 0 && ret != li->status_out) {
        link_set_out_status(link, ret, AV_NOPTS_VALUE);
    } else {
        /* Run once again, to see if several frames were available, or if
@@ -1142,18 +1162,21 @@ static int ff_filter_frame_to_filter(AVFilterLink *link)
    return ret;
 }

-static int forward_status_change(AVFilterContext *filter, AVFilterLink *in)
+static int forward_status_change(AVFilterContext *filter, FilterLinkInternal *li_in)
 {
+    AVFilterLink *in = &li_in->l;
    unsigned out = 0, progress = 0;
    int ret;

-    av_assert0(!in->status_out);
+    av_assert0(!li_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) {
+    while (!li_in->status_out) {
+        FilterLinkInternal *li_out = ff_link_internal(filter->outputs[out]);
+
+        if (!li_out->status_in) {
            progress++;
            ret = ff_request_frame_to_filter(filter->outputs[out]);
            if (ret < 0)
@@ -1163,7 +1186,7 @@ static int forward_status_change(AVFilterContext *filter, AVFilterLink *in)
            if (!progress) {
                /* Every output already closed: input no longer interesting
                   (example: overlay in shortest mode, other input closed). */
-                link_set_out_status(in, in->status_in, in->status_in_pts);
+                link_set_out_status(in, li_in->status_in, li_in->status_in_pts);
                return 0;
            }
            progress = 0;
@@ -1179,7 +1202,8 @@ static int ff_filter_activate_default(AVFilterContext *filter)
    unsigned i;

    for (i = 0; i < filter->nb_outputs; i++) {
-        int ret = filter->outputs[i]->status_in;
+        FilterLinkInternal *li = ff_link_internal(filter->outputs[i]);
+        int ret = li->status_in;

        if (ret) {
            for (int j = 0; j < filter->nb_inputs; j++)
@@ -1189,19 +1213,22 @@ static int ff_filter_activate_default(AVFilterContext *filter)
    }

    for (i = 0; i < filter->nb_inputs; i++) {
-        if (samples_ready(filter->inputs[i], filter->inputs[i]->min_samples)) {
+        if (samples_ready(ff_link_internal(filter->inputs[i]),
+                          filter->inputs[i]->min_samples)) {
            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]);
+        FilterLinkInternal * const li = ff_link_internal(filter->inputs[i]);
+        if (li->status_in && !li->status_out) {
+            av_assert1(!ff_framequeue_queued_frames(&li->fifo));
+            return forward_status_change(filter, li);
        }
    }
    for (i = 0; i < filter->nb_outputs; i++) {
+        FilterLinkInternal * const li = ff_link_internal(filter->outputs[i]);
        if (filter->outputs[i]->frame_wanted_out &&
-            !filter->outputs[i]->frame_blocked_in) {
+            !li->frame_blocked_in) {
            return ff_request_frame_to_filter(filter->outputs[i]);
        }
    }
@@ -1357,39 +1384,44 @@ int ff_filter_activate(AVFilterContext *filter)

 int ff_inlink_acknowledge_status(AVFilterLink *link, int *rstatus, int64_t *rpts)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
    *rpts = link->current_pts;
-    if (ff_framequeue_queued_frames(&link->fifo))
+    if (ff_framequeue_queued_frames(&li->fifo))
        return *rstatus = 0;
-    if (link->status_out)
-        return *rstatus = link->status_out;
-    if (!link->status_in)
+    if (li->status_out)
+        return *rstatus = li->status_out;
+    if (!li->status_in)
        return *rstatus = 0;
-    *rstatus = link->status_out = link->status_in;
-    update_link_current_pts(link, link->status_in_pts);
+    *rstatus = li->status_out = li->status_in;
+    update_link_current_pts(link, li->status_in_pts);
    *rpts = link->current_pts;
    return 1;
 }

 size_t ff_inlink_queued_frames(AVFilterLink *link)
 {
-    return ff_framequeue_queued_frames(&link->fifo);
+    FilterLinkInternal * const li = ff_link_internal(link);
+    return ff_framequeue_queued_frames(&li->fifo);
 }

 int ff_inlink_check_available_frame(AVFilterLink *link)
 {
-    return ff_framequeue_queued_frames(&link->fifo) > 0;
+    FilterLinkInternal * const li = ff_link_internal(link);
+    return ff_framequeue_queued_frames(&li->fifo) > 0;
 }

 int ff_inlink_queued_samples(AVFilterLink *link)
 {
-    return ff_framequeue_queued_samples(&link->fifo);
+    FilterLinkInternal * const li = ff_link_internal(link);
+    return ff_framequeue_queued_samples(&li->fifo);
 }

 int ff_inlink_check_available_samples(AVFilterLink *link, unsigned min)
 {
-    uint64_t samples = ff_framequeue_queued_samples(&link->fifo);
+    FilterLinkInternal * const li = ff_link_internal(link);
+    uint64_t samples = ff_framequeue_queued_samples(&li->fifo);
    av_assert1(min);
-    return samples >= min || (link->status_in && samples);
+    return samples >= min || (li->status_in && samples);
 }

 static void consume_update(AVFilterLink *link, const AVFrame *frame)
@@ -1403,18 +1435,19 @@ static void consume_update(AVFilterLink *link, const AVFrame *frame)

 int ff_inlink_consume_frame(AVFilterLink *link, AVFrame **rframe)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
    AVFrame *frame;

    *rframe = NULL;
    if (!ff_inlink_check_available_frame(link))
        return 0;

-    if (link->fifo.samples_skipped) {
-        frame = ff_framequeue_peek(&link->fifo, 0);
+    if (li->fifo.samples_skipped) {
+        frame = ff_framequeue_peek(&li->fifo, 0);
        return ff_inlink_consume_samples(link, frame->nb_samples, frame->nb_samples, rframe);
    }

-    frame = ff_framequeue_take(&link->fifo);
+    frame = ff_framequeue_take(&li->fifo);
    consume_update(link, frame);
    *rframe = frame;
    return 1;
@@ -1423,6 +1456,7 @@ int ff_inlink_consume_frame(AVFilterLink *link, AVFrame **rframe)
 int ff_inlink_consume_samples(AVFilterLink *link, unsigned min, unsigned max,
                            AVFrame **rframe)
 {
+    FilterLinkInternal * const li = ff_link_internal(link);
    AVFrame *frame;
    int ret;

@@ -1430,9 +1464,9 @@ int ff_inlink_consume_samples(AVFilterLink *link, unsigned min, unsigned max,
    *rframe = NULL;
    if (!ff_inlink_check_available_samples(link, min))
        return 0;
-    if (link->status_in)
-        min = FFMIN(min, ff_framequeue_queued_samples(&link->fifo));
-    ret = take_samples(link, min, max, &frame);
+    if (li->status_in)
+        min = FFMIN(min, ff_framequeue_queued_samples(&li->fifo));
+    ret = take_samples(li, min, max, &frame);
    if (ret < 0)
        return ret;
    consume_update(link, frame);
@@ -1442,7 +1476,8 @@ int ff_inlink_consume_samples(AVFilterLink *link, unsigned min, unsigned max,

 AVFrame *ff_inlink_peek_frame(AVFilterLink *link, size_t idx)
 {
-    return ff_framequeue_peek(&link->fifo, idx);
+    FilterLinkInternal * const li = ff_link_internal(link);
+    return ff_framequeue_peek(&li->fifo, idx);
 }

 int ff_inlink_make_frame_writable(AVFilterLink *link, AVFrame **rframe)
@@ -1534,29 +1569,32 @@ void ff_inlink_request_frame(AVFilterLink *link)

 void ff_inlink_set_status(AVFilterLink *link, int status)
 {
-    if (link->status_out)
+    FilterLinkInternal * const li = ff_link_internal(link);
+    if (li->status_out)
        return;
    link->frame_wanted_out = 0;
-    link->frame_blocked_in = 0;
+    li->frame_blocked_in = 0;
    link_set_out_status(link, status, AV_NOPTS_VALUE);
-    while (ff_framequeue_queued_frames(&link->fifo)) {
-           AVFrame *frame = ff_framequeue_take(&link->fifo);
+    while (ff_framequeue_queued_frames(&li->fifo)) {
+           AVFrame *frame = ff_framequeue_take(&li->fifo);
           av_frame_free(&frame);
    }
-    if (!link->status_in)
-        link->status_in = status;
+    if (!li->status_in)
+        li->status_in = status;
 }

 int ff_outlink_get_status(AVFilterLink *link)
 {
-    return link->status_in;
+    FilterLinkInternal * const li = ff_link_internal(link);
+    return li->status_in;
 }

 int ff_inoutlink_check_flow(AVFilterLink *inlink, AVFilterLink *outlink)
 {
+    FilterLinkInternal * const li_in = ff_link_internal(inlink);
    return ff_outlink_frame_wanted(outlink) ||
           ff_inlink_check_available_frame(inlink) ||
-           inlink->status_out;
+           li_in->status_out;
 }


--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -695,51 +695,6 @@ struct AVFilterLink {
     * AVHWFramesContext describing the frames.
     */
    AVBufferRef *hw_frames_ctx;
-
-#ifndef FF_INTERNAL_FIELDS
-
-    /**
-     * Internal structure members.
-     * The fields below this limit are internal for libavfilter's use
-     * and must in no way be accessed by applications.
-     */
-    char reserved[0xF000];
-
-#else /* FF_INTERNAL_FIELDS */
-
-    /**
-     * Queue of frames waiting to be filtered.
-     */
-    FFFrameQueue fifo;
-
-    /**
-     * If set, the source filter can not generate a frame as is.
-     * The goal is to avoid repeatedly calling the request_frame() method on
-     * the same link.
-     */
-    int frame_blocked_in;
-
-    /**
-     * Link input status.
-     * If not zero, all attempts of filter_frame will fail with the
-     * corresponding code.
-     */
-    int status_in;
-
-    /**
-     * Timestamp of the input status change.
-     */
-    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;
-
-#endif /* FF_INTERNAL_FIELDS */
-
 };

 /**
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -32,13 +32,13 @@
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"

-#define FF_INTERNAL_FIELDS 1
-#include "framequeue.h"

 #include "avfilter.h"
 #include "buffersink.h"
 #include "formats.h"
+#include "framequeue.h"
 #include "internal.h"
+#include "link_internal.h"
 #include "thread.h"

 #define OFFSET(x) offsetof(AVFilterGraph, x)
@@ -1483,10 +1483,11 @@ int avfilter_graph_request_oldest(AVFilterGraph *graph)
    av_assert1(oldest->age_index >= 0);
    frame_count = oldest->frame_count_out;
    while (frame_count == oldest->frame_count_out) {
+        FilterLinkInternal * const li = ff_link_internal(oldest);
        r = ff_filter_graph_run_once(graph);
        if (r == AVERROR(EAGAIN) &&
-            !oldest->frame_wanted_out && !oldest->frame_blocked_in &&
-            !oldest->status_in)
+            !oldest->frame_wanted_out && !li->frame_blocked_in &&
+            !li->status_in)
            ff_request_frame(oldest);
        else if (r < 0)
            return r;
--- a/libavfilter/buffersink.c
+++ b/libavfilter/buffersink.c
@@ -30,15 +30,14 @@
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"

-#define FF_INTERNAL_FIELDS 1
-#include "framequeue.h"
-
 #include "audio.h"
 #include "avfilter.h"
 #include "buffersink.h"
 #include "filters.h"
 #include "formats.h"
+#include "framequeue.h"
 #include "internal.h"
+#include "link_internal.h"
 #include "video.h"

 typedef struct BufferSinkContext {
@@ -178,9 +177,10 @@ static void uninit(AVFilterContext *ctx)
 static int activate(AVFilterContext *ctx)
 {
    BufferSinkContext *buf = ctx->priv;
+    FilterLinkInternal * const li = ff_link_internal(ctx->inputs[0]);

    if (buf->warning_limit &&
-        ff_framequeue_queued_frames(&ctx->inputs[0]->fifo) >= buf->warning_limit) {
+        ff_framequeue_queued_frames(&li->fifo) >= buf->warning_limit) {
        av_log(ctx, AV_LOG_WARNING,
               "%d buffers queued in %s, something may be wrong.\n",
               buf->warning_limit,
--- a/libavfilter/link_internal.h
+++ b/libavfilter/link_internal.h
@@ -0,0 +1,69 @@
+/*
+ * Internal filter link API
+ *
+ * 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
+ */
+
+#ifndef AVFILTER_LINK_INTERNAL_H
+#define AVFILTER_LINK_INTERNAL_H
+
+#include <stdint.h>
+
+#include "avfilter.h"
+#include "framequeue.h"
+
+typedef struct FilterLinkInternal {
+    AVFilterLink l;
+
+    /**
+     * Queue of frames waiting to be filtered.
+     */
+    FFFrameQueue fifo;
+
+    /**
+     * If set, the source filter can not generate a frame as is.
+     * The goal is to avoid repeatedly calling the request_frame() method on
+     * the same link.
+     */
+    int frame_blocked_in;
+
+    /**
+     * Link input status.
+     * If not zero, all attempts of filter_frame will fail with the
+     * corresponding code.
+     */
+    int status_in;
+
+    /**
+     * Timestamp of the input status change.
+     */
+    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;
+} FilterLinkInternal;
+
+static inline FilterLinkInternal *ff_link_internal(AVFilterLink *link)
+{
+    return (FilterLinkInternal*)link;
+}
+
+#endif /* AVFILTER_LINK_INTERNAL_H */
--- a/libavfilter/tests/filtfmts.c
+++ b/libavfilter/tests/filtfmts.c
@@ -25,12 +25,11 @@
 #include "libavutil/pixdesc.h"
 #include "libavutil/samplefmt.h"

-#define FF_INTERNAL_FIELDS 1
-#include "libavfilter/framequeue.h"
-
 #include "libavfilter/avfilter.h"
 #include "libavfilter/formats.h"
+#include "libavfilter/framequeue.h"
 #include "libavfilter/internal.h"
+#include "libavfilter/link_internal.h"

 static void print_formats_internal(AVFilterLink **links, const AVFilterPad *pads,
                                   unsigned nb, size_t fmts_cfg_offset,
@@ -123,7 +122,7 @@ int main(int argc, char **argv)

    /* create a link for each of the input pads */
    for (i = 0; i < filter_ctx->nb_inputs; i++) {
-        AVFilterLink *link = av_mallocz(sizeof(AVFilterLink));
+        AVFilterLink *link = av_mallocz(sizeof(FilterLinkInternal));
        if (!link) {
            fprintf(stderr, "Unable to allocate memory for filter input link\n");
            ret = 1;
@@ -133,7 +132,7 @@ int main(int argc, char **argv)
        filter_ctx->inputs[i] = link;
    }
    for (i = 0; i < filter_ctx->nb_outputs; i++) {
-        AVFilterLink *link = av_mallocz(sizeof(AVFilterLink));
+        AVFilterLink *link = av_mallocz(sizeof(FilterLinkInternal));
        if (!link) {
            fprintf(stderr, "Unable to allocate memory for filter output link\n");
            ret = 1;