Revert "Revert "lavfi/buffersrc: push the frame deeper if requested.""

This reverts commit 04aa09c4
and reintroduces 0ff5567a that
was temporarily reverted due to minor regressions.

It also reverts e5bce8b4 that fixed FATE refs.
The fate-ffm change is caused by field_order now being set
on the output format because the first frame arrives earlier.
The fate-mxf change is assumed to be the same.

libavfilter/buffersrc.c

@@ -173,6 +173,20 @@ int attribute_align_arg av_buffersrc_add_frame_flags(AVFilterContext *ctx, AVFra
     return ret;
 }
 
+static int push_frame(AVFilterGraph *graph)
+{
+    int ret;
+
+    while (1) {
+        ret = ff_filter_graph_run_once(graph);
+        if (ret == AVERROR(EAGAIN))
+            break;
+        if (ret < 0)
+            return ret;
+    }
+    return 0;
+}
+
 static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
                                            AVFrame *frame, int flags)
 {
@@ -185,6 +199,11 @@ 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);
+        if ((flags & AV_BUFFERSRC_FLAG_PUSH)) {
+            ret = push_frame(ctx->graph);
+            if (ret < 0)
+                return ret;
+        }
         return 0;
     } else if (s->eof)
         return AVERROR(EINVAL);
@@ -239,6 +258,12 @@ static int av_buffersrc_add_frame_internal(AVFilterContext *ctx,
     if ((ret = ctx->output_pads[0].request_frame(ctx->outputs[0])) < 0)
         return ret;
 
+    if ((flags & AV_BUFFERSRC_FLAG_PUSH)) {
+        ret = push_frame(ctx->graph);
+        if (ret < 0)
+            return ret;
+    }
+
     return 0;
 }
 

tests/ref/lavf/ffm

-a0e9616f0d9a8c1029f3220b1b9175f4 *./tests/data/lavf/lavf.ffm
+ca2a450cd0d1e299514a345923b4c82a *./tests/data/lavf/lavf.ffm
 376832 ./tests/data/lavf/lavf.ffm
 ./tests/data/lavf/lavf.ffm CRC=0x000e23ae

tests/ref/lavf/mxf

-dbdbb7d8677dc29b0d90eedcf418ce13 *./tests/data/lavf/lavf.mxf
+eaac3125ac1a61fe5f968c7af83fa71e *./tests/data/lavf/lavf.mxf
 525369 ./tests/data/lavf/lavf.mxf
 ./tests/data/lavf/lavf.mxf CRC=0x8dddfaab
-40fcb0a898f8825a17f5754b23762f49 *./tests/data/lavf/lavf.mxf
+1562530330b13e9e70f522fe20265632 *./tests/data/lavf/lavf.mxf
 560697 ./tests/data/lavf/lavf.mxf
 ./tests/data/lavf/lavf.mxf CRC=0xf21b1b48
-9233d192af20fc2a89304f5ae93c21ee *./tests/data/lavf/lavf.mxf
+e07858715997313ae66a1cdd6fde5f66 *./tests/data/lavf/lavf.mxf
 525369 ./tests/data/lavf/lavf.mxf
 ./tests/data/lavf/lavf.mxf CRC=0x8dddfaab