dvdemux: Fix detection of new media

There are 5 or 6 AAUX source control packs in a frame, and any
of them could have REC_ST cleared, indicating a recording start
point.  libdv only checks the first.

2 files changed, 33 insertions, 1 deletions

diff --git a/ext/dv/gstdvdemux.c b/ext/dv/gstdvdemux.c
index 6f33ac60..22afd851 100644
--- a/ext/dv/gstdvdemux.c
+++ b/ext/dv/gstdvdemux.c
@@ -1356,6 +1356,31 @@ gst_dvdemux_demux_video (GstDVDemux * dvdemux, GstBuffer * buffer,
   return ret;
 }
 
+static gboolean
+gst_dvdemux_is_new_media (GstDVDemux * dvdemux, GstBuffer * buffer)
+{
+  guint8 *data = GST_BUFFER_DATA (buffer);
+  int aaux_offset;
+  int dif;
+  int n_difs;
+
+  n_difs = dvdemux->PAL ? 12 : 10;
+
+  for (dif = 0; dif < n_difs; dif++) {
+    if (dif & 1) {
+      aaux_offset = (dif * 12000) + (6 + 16 * 1) * 80 + 3;
+    } else {
+      aaux_offset = (dif * 12000) + (6 + 16 * 4) * 80 + 3;
+    }
+    if (data[aaux_offset + 0] == 0x51) {
+      if ((data[aaux_offset + 2] & 0x80) == 0)
+        return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
 /* takes ownership of buffer */
 static GstFlowReturn
 gst_dvdemux_demux_frame (GstDVDemux * dvdemux, GstBuffer * buffer)
@@ -1410,7 +1435,13 @@ gst_dvdemux_demux_frame (GstDVDemux * dvdemux, GstBuffer * buffer)
   data = GST_BUFFER_DATA (buffer);
 
   dv_parse_packs (dvdemux->decoder, data);
-  dvdemux->new_media = dv_is_new_recording (dvdemux->decoder, data);
+  dvdemux->new_media = FALSE;
+  if (gst_dvdemux_is_new_media (dvdemux, buffer) &&
+      dvdemux->frames_since_new_media > 2) {
+    dvdemux->new_media = TRUE;
+    dvdemux->frames_since_new_media = 0;
+  }
+  dvdemux->frames_since_new_media++;
 
   /* does not take ownership of buffer */
   aret = ret = gst_dvdemux_demux_audio (dvdemux, buffer, duration);
diff --git a/ext/dv/gstdvdemux.h b/ext/dv/gstdvdemux.h
index e7dd0c6d..b77f4f46 100644
--- a/ext/dv/gstdvdemux.h
+++ b/ext/dv/gstdvdemux.h
@@ -80,6 +80,7 @@ struct _GstDVDemux {
   gboolean       running;
   gboolean       need_segment;
   gboolean       new_media;
+  int            frames_since_new_media;
   
   gint           found_header; /* ATOMIC */
   GstEvent      *seek_event;