movenc: Add a test for VFR with b-frames, with a duration change at a fragment end

Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/tests/movenc.c

@@ -70,6 +70,8 @@ int skip_write;
 int skip_write_audio;
 int clear_duration;
 int force_iobuf_size;
+int do_interleave;
+int fake_pkt_duration;
 
 int num_warnings;
 
@@ -283,6 +285,8 @@ static void mux_frames(int n)
             }
             if (!bframes)
                 pkt.pts = pkt.dts;
+            if (fake_pkt_duration)
+                pkt.duration = fake_pkt_duration;
             frames++;
         }
 
@@ -295,7 +299,10 @@ static void mux_frames(int n)
             continue;
         if (skip_write_audio && pkt.stream_index == 1)
             continue;
-        av_write_frame(ctx, &pkt);
+        if (do_interleave)
+            av_interleaved_write_frame(ctx, &pkt);
+        else
+            av_write_frame(ctx, &pkt);
     }
 }
 
@@ -709,6 +716,32 @@ int main(int argc, char **argv)
     close_out();
     force_iobuf_size = 0;
 
+    // Test VFR content with bframes with interleaving.
+    // Here, using av_interleaved_write_frame allows the muxer to get the
+    // fragment end durations right. We always set the packet duration to
+    // the expected, but we simulate dropped frames at one point.
+    do_interleave = 1;
+    init_out("vfr-noduration-interleave");
+    av_dict_set(&opts, "movflags", "frag_keyframe+delay_moov", 0);
+    av_dict_set(&opts, "frag_duration", "650000", 0);
+    init_fps(1, 1, 30);
+    mux_frames(gop_size/2);
+    // Pretend that the packet duration is the normal, even if
+    // we actually skip a bunch of frames. (I.e., simulate that
+    // we don't know of the framedrop in advance.)
+    fake_pkt_duration = duration;
+    duration *= 10;
+    mux_frames(1);
+    fake_pkt_duration = 0;
+    duration /= 10;
+    mux_frames(gop_size/2 - 1);
+    mux_gops(1);
+    finish();
+    close_out();
+    clear_duration = 0;
+    do_interleave = 0;
+
+
     av_free(md5);
 
     return check_faults > 0 ? 1 : 0;

tests/ref/fate/movenc

@@ -125,3 +125,11 @@ write_data len 1500, time 9666667, type sync atom moof
 write_data len 664, time nopts, type unknown atom -
 write_data len 148, time nopts, type trailer atom -
 03766894d839e5fcb1edb88498d812f7 5687 large_frag
+write_data len 1255, time nopts, type header atom ftyp
+write_data len 508, time -33333, type sync atom moof
+write_data len 372, time 800000, type boundary atom moof
+write_data len 328, time 1266667, type boundary atom moof
+write_data len 476, time 1566667, type sync atom moof
+write_data len 340, time 2233333, type boundary atom moof
+write_data len 262, time nopts, type trailer atom -
+a4280bdc23af2c4334ec2da3fa946d3a 3541 vfr-noduration-interleave