matroskamux: make default duration check less sensitive

Frame duration might vary for 1 usecond, in this case matroskamux
decides to create BLOCKGROUP instead of SIMPLEBLOCK.

Convert duration to timecodescale which is (typically) less precise, and
then also allow the difference of 1/-1 to arrange for less sensitive check.

Based on patch by Alexey Fisher <bug-track@fisher-privat.net>

Fixes #653080.

diff --git a/gst/matroska/matroska-mux.c b/gst/matroska/matroska-mux.c
index 2a639d4..ed98df1 100644 (file)
--- a/gst/matroska/matroska-mux.c
+++ b/gst/matroska/matroska-mux.c
@@ -2204,6 +2204,10 @@ gst_matroska_mux_start (GstMatroskaMux * mux)
       child = gst_ebml_write_master_start (ebml, GST_MATROSKA_ID_TRACKENTRY);
       gst_matroska_mux_track_header (mux, collect_pad->track);
       gst_ebml_write_master_finish (ebml, child);
+      /* some remaing pad/track setup */
+      collect_pad->default_duration_scaled =
+          gst_util_uint64_scale (collect_pad->track->default_duration,
+          1, mux->time_scale);
     }
   }
   gst_ebml_write_master_finish (ebml, master);
@@ -2767,9 +2771,14 @@ gst_matroska_mux_write_data (GstMatroskaMux * mux, GstMatroskaPad * collect_pad)
 
   /* Check if the duration differs from the default duration. */
   write_duration = FALSE;
-  block_duration = GST_BUFFER_DURATION (buf);
+  block_duration = 0;
   if (GST_BUFFER_DURATION_IS_VALID (buf)) {
-    if (block_duration != collect_pad->track->default_duration) {
+    block_duration = gst_util_uint64_scale (GST_BUFFER_DURATION (buf),
+        1, mux->time_scale);
+
+    /* small difference should be ok. */
+    if (block_duration > collect_pad->default_duration_scaled + 1 ||
+        block_duration < collect_pad->default_duration_scaled - 1) {
       write_duration = TRUE;
     }
   }
@@ -2810,10 +2819,8 @@ gst_matroska_mux_write_data (GstMatroskaMux * mux, GstMatroskaPad * collect_pad)
     hdr =
         gst_matroska_mux_create_buffer_header (collect_pad->track,
         relative_timestamp, 0);
-    if (write_duration) {
-      gst_ebml_write_uint (ebml, GST_MATROSKA_ID_BLOCKDURATION,
-          gst_util_uint64_scale (block_duration, 1, mux->time_scale));
-    }
+    if (write_duration)
+      gst_ebml_write_uint (ebml, GST_MATROSKA_ID_BLOCKDURATION, block_duration);
     gst_ebml_write_buffer_header (ebml, GST_MATROSKA_ID_BLOCK,
         GST_BUFFER_SIZE (buf) + GST_BUFFER_SIZE (hdr));
     gst_ebml_write_buffer (ebml, hdr);

diff --git a/gst/matroska/matroska-mux.h b/gst/matroska/matroska-mux.h
index 1270072..e5074a7 100644 (file)
--- a/gst/matroska/matroska-mux.h
+++ b/gst/matroska/matroska-mux.h
@@ -64,6 +64,7 @@ typedef struct
   guint64 duration;
   GstClockTime start_ts;
   GstClockTime end_ts;    /* last timestamp + (if available) duration */
+  guint64 default_duration_scaled;
 }
 GstMatroskaPad;