qtdemux: Fix premature EOS when some files are played in push mode

Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/2771

This EOS branch exists so that if a seek with a stop is made, qtdemux
stops accepting bytes from the sink after the entire requested playback
range is demuxed, as otherwise we could keep download content that is
not being used.

This patch fixes two flaws that were present in that EOS check:

1) A comparison was made between track time and movie time without conversion.
This made the check trigger early in files with edit lists. This patch fixes
this by converting the track PTS to movie PTS (stream time) for the check.

2) To avoid sending a EOS prematurely when the segment stop is within a GOP and
B-frames are present, the check for EOS should only be done for keyframes. I
gather this was already the intention with the existing code, but because it
used `stream->on_keyframe` instead of the local variable `keyframe` the old
code was checking if the *previous* frame was a keyframe.

It's interesting to note that these two flaws in the old code mask each other
in most cases: the track PTS will have reached the movie end PTS, but EOS would
only be sent if the previous frame was a keyframe. A simple case where they
wouldn't mask each other, reproducing the bug, is a sequence of 3 frame GOPs
with structure I-B-P.

The following validateflow tests have been added to future-proof the
fix:

 * validate.test.mp4.qtdemux_ibpibp_non_frag_pull.default
 * validate.test.mp4.qtdemux_ibpibp_non_frag_push.default

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5021>

subprojects/gst-integration-testsuites/medias

@@ -1 +1 @@
-Subproject commit 4325f3ae114e8e5d160c34cd02634fb4f36f52db
+Subproject commit 121f8909493df214564c3db7fbba1dcb9217348e

subprojects/gst-integration-testsuites/testsuites/validate.testslist

@@ -940,6 +940,8 @@ validate.test.interlace.interlace_deinterlace
 validate.test.interlace.interlace_deinterlace_alternate
 validate.test.matroska.demux_flush_within_cluster.default
 validate.test.mp4.qtdemux_change_edit_list.default
+validate.test.mp4.qtdemux_ibpibp_non_frag_pull.default
+validate.test.mp4.qtdemux_ibpibp_non_frag_push.default
 validate.test.mp4.qtdemux_reverse_playback_full_gop.reverse_playback_full_gop
 validate.test.mp4.redirect.play_15s
 validate.test.mse.segment_future_past_mse

subprojects/gst-integration-testsuites/testsuites/validate/mp4/qtdemux_ibpibp_non_frag_pull.default.validatetest

@@ -0,0 +1,11 @@
+set-globals, media_dir="$(test_dir)/../../../medias/"
+meta,
+    seek=false,
+    handles-states=false,
+    args = {
+         "filesrc location=\"$(media_dir)/edit-lists/simple/ibpibp-non-frag.mp4\" ! qtdemux ! fakesink async=false",
+    },
+    configs = {
+       "$(validateflow), pad=fakesink0:sink, record-buffers=true, logged-event-types={segment}",
+        "change-issue-severity, issue-id=event::eos-has-wrong-seqnum, new-severity=ignore",
+    }

subprojects/gst-integration-testsuites/testsuites/validate/mp4/qtdemux_ibpibp_non_frag_pull.default/flow-expectations/log-fakesink0-sink-expected

@@ -0,0 +1,7 @@
+event segment: format=TIME, start=0:00:00.333333333, offset=0:00:00.000000000, stop=0:00:02.333333333, time=0:00:00.000000000, base=0:00:00.000000000, position=0:00:00.333333333
+buffer: dts=0:00:00.000000000, pts=0:00:00.333333333, dur=0:00:00.333333333, flags=discont
+buffer: dts=0:00:00.333333333, pts=0:00:01.000000000, dur=0:00:00.333333333, flags=delta-unit
+buffer: dts=0:00:00.666666666, pts=0:00:00.666666666, dur=0:00:00.333333334, flags=delta-unit
+buffer: dts=0:00:01.000000000, pts=0:00:01.333333333, dur=0:00:00.333333333
+buffer: dts=0:00:01.333333333, pts=0:00:02.000000000, dur=0:00:00.333333333, flags=delta-unit
+buffer: dts=0:00:01.666666666, pts=0:00:01.666666666, dur=0:00:00.333333334, flags=delta-unit

subprojects/gst-integration-testsuites/testsuites/validate/mp4/qtdemux_ibpibp_non_frag_push.default.validatetest

@@ -0,0 +1,15 @@
+set-globals, media_dir="$(test_dir)/../../../medias/"
+meta,
+    seek=false,
+    handles-states=false,
+    args = {
+         "appsrc ! qtdemux ! fakesink async=false",
+    },
+    configs = {
+       "$(validateflow), pad=fakesink0:sink, record-buffers=true, logged-event-types={segment, eos}",
+        "change-issue-severity, issue-id=event::eos-has-wrong-seqnum, new-severity=ignore",
+    }
+
+# Note that sending the file this way ensures qtdemux doesn't receive an EOS
+# from appsrc, so we can test that the EOS comes from qtdemux.
+appsrc-push, target-element-name=appsrc0, file-name="$(media_dir)/edit-lists/simple/ibpibp-non-frag.mp4"

subprojects/gst-integration-testsuites/testsuites/validate/mp4/qtdemux_ibpibp_non_frag_push.default/flow-expectations/log-fakesink0-sink-expected

@@ -0,0 +1,8 @@
+event segment: format=TIME, start=0:00:00.333333333, offset=0:00:00.000000000, stop=0:00:02.333333333, time=0:00:00.000000000, base=0:00:00.000000000, position=0:00:00.333333333
+buffer: dts=0:00:00.000000000, pts=0:00:00.333333333, dur=0:00:00.333333333, flags=discont tag-memory
+buffer: dts=0:00:00.333333333, pts=0:00:01.000000000, dur=0:00:00.333333333, flags=delta-unit tag-memory
+buffer: dts=0:00:00.666666666, pts=0:00:00.666666666, dur=0:00:00.333333334, flags=delta-unit tag-memory
+buffer: dts=0:00:01.000000000, pts=0:00:01.333333333, dur=0:00:00.333333333, flags=tag-memory
+buffer: dts=0:00:01.333333333, pts=0:00:02.000000000, dur=0:00:00.333333333, flags=delta-unit tag-memory
+buffer: dts=0:00:01.666666666, pts=0:00:01.666666666, dur=0:00:00.333333334, flags=delta-unit tag-memory
+event eos: (no structure)

subprojects/gst-plugins-good/gst/isomp4/qtdemux.c

@@ -7882,6 +7882,42 @@ gst_qtdemux_chain (GstPad * sinkpad, GstObject * parent, GstBuffer * inbuf)
   return gst_qtdemux_process_adapter (demux, FALSE);
 }
 
+static guint64
+gst_segment_to_stream_time_clamped (const GstSegment * segment,
+    guint64 position)
+{
+  guint64 segment_stream_time_start;
+  guint64 segment_stream_time_stop = GST_CLOCK_TIME_NONE;
+  guint64 stream_pts_unsigned;
+  int ret;
+
+  g_return_val_if_fail (segment != NULL, GST_CLOCK_TIME_NONE);
+  g_return_val_if_fail (segment->format == GST_FORMAT_TIME,
+      GST_CLOCK_TIME_NONE);
+
+  segment_stream_time_start = segment->time;
+  if (segment->stop != GST_CLOCK_TIME_NONE)
+    segment_stream_time_stop =
+        gst_segment_to_stream_time (segment, GST_FORMAT_TIME, segment->stop);
+
+  ret =
+      gst_segment_to_stream_time_full (segment, GST_FORMAT_TIME, position,
+      &stream_pts_unsigned);
+  /* ret == 0 if the segment is invalid (either position, segment->time or the segment start are -1). */
+  g_return_val_if_fail (ret != 0, GST_CLOCK_TIME_NONE);
+
+  if (ret == -1 || stream_pts_unsigned < segment_stream_time_start) {
+    /* Negative or prior to segment start stream time, clamp to segment start. */
+    return segment_stream_time_start;
+  } else if (segment_stream_time_stop != GST_CLOCK_TIME_NONE
+      && stream_pts_unsigned > segment_stream_time_stop) {
+    /* Clamp to segment end. */
+    return segment_stream_time_stop;
+  } else {
+    return stream_pts_unsigned;
+  }
+}
+
 static GstFlowReturn
 gst_qtdemux_process_adapter (GstQTDemux * demux, gboolean force)
 {
@@ -8290,7 +8326,7 @@ gst_qtdemux_process_adapter (GstQTDemux * demux, gboolean force)
       case QTDEMUX_STATE_MOVIE:{
         QtDemuxStream *stream = NULL;
         QtDemuxSample *sample;
-        GstClockTime dts, pts, duration;
+        GstClockTime dts, pts, stream_pts, duration;
         gboolean keyframe;
         gint i;
 
@@ -8402,12 +8438,14 @@ gst_qtdemux_process_adapter (GstQTDemux * demux, gboolean force)
 
           dts = QTSAMPLE_DTS (stream, sample);
           pts = QTSAMPLE_PTS (stream, sample);
+          stream_pts =
+              gst_segment_to_stream_time_clamped (&stream->segment, pts);
           duration = QTSAMPLE_DUR_DTS (stream, sample, dts);
           keyframe = QTSAMPLE_KEYFRAME (stream, sample);
 
           /* check for segment end */
           if (G_UNLIKELY (demux->segment.stop != -1
-                  && demux->segment.stop <= pts && stream->on_keyframe)
+                  && demux->segment.stop <= stream_pts && keyframe)
               && !(demux->upstream_format_is_time && demux->segment.rate < 0)) {
             GST_DEBUG_OBJECT (demux, "we reached the end of our segment.");
             stream->time_position = GST_CLOCK_TIME_NONE;        /* this means EOS */