movenc: Write a 0 duration in mdhd and tkhd for an empty initial moov

ISO/IEC 14496-12:2012/Cor 1:2013 is explicit about how this should be
handled. All zeros doesn't mean that the full file has got a zero
duration, only that the track samples described within the initial moov
have got zero duration. An all ones duration means an indeterminate
duration.

Keep writing a duration consisting of all ones for the ISM mode -
older windows media player versions won't play a file if this is
zero. (Newer windows media player versions play either version fine.)

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

libavformat/movenc.c

@@ -1434,7 +1434,8 @@ static int mov_write_minf_tag(AVIOContext *pb, MOVTrack *track)
     return update_size(pb, pos);
 }
 
-static int mov_write_mdhd_tag(AVIOContext *pb, MOVTrack *track)
+static int mov_write_mdhd_tag(AVIOContext *pb, MOVMuxContext *mov,
+                              MOVTrack *track)
 {
     int version = track->track_duration < INT32_MAX ? 0 : 1;
 
@@ -1453,8 +1454,10 @@ static int mov_write_mdhd_tag(AVIOContext *pb, MOVTrack *track)
         avio_wb32(pb, track->time); /* modification time */
     }
     avio_wb32(pb, track->timescale); /* time scale (sample rate for audio) */
-    if (!track->entry)
+    if (!track->entry && mov->mode == MODE_ISM)
         (version == 1) ? avio_wb64(pb, UINT64_C(0xffffffffffffffff)) : avio_wb32(pb, 0xffffffff);
+    else if (!track->entry)
+        (version == 1) ? avio_wb64(pb, 0) : avio_wb32(pb, 0);
     else
         (version == 1) ? avio_wb64(pb, track->track_duration) : avio_wb32(pb, track->track_duration); /* duration */
     avio_wb16(pb, track->language); /* language */
@@ -1470,12 +1473,13 @@ static int mov_write_mdhd_tag(AVIOContext *pb, MOVTrack *track)
     return 32;
 }
 
-static int mov_write_mdia_tag(AVIOContext *pb, MOVTrack *track)
+static int mov_write_mdia_tag(AVIOContext *pb, MOVMuxContext *mov,
+                              MOVTrack *track)
 {
     int64_t pos = avio_tell(pb);
     avio_wb32(pb, 0); /* size */
     ffio_wfourcc(pb, "mdia");
-    mov_write_mdhd_tag(pb, track);
+    mov_write_mdhd_tag(pb, mov, track);
     mov_write_hdlr_tag(pb, track);
     mov_write_minf_tag(pb, track);
     return update_size(pb, pos);
@@ -1517,8 +1521,10 @@ static int mov_write_tkhd_tag(AVIOContext *pb, MOVMuxContext *mov,
     }
     avio_wb32(pb, track->track_id); /* track-id */
     avio_wb32(pb, 0); /* reserved */
-    if (!track->entry)
+    if (!track->entry && mov->mode == MODE_ISM)
         (version == 1) ? avio_wb64(pb, UINT64_C(0xffffffffffffffff)) : avio_wb32(pb, 0xffffffff);
+    else if (!track->entry)
+        (version == 1) ? avio_wb64(pb, 0) : avio_wb32(pb, 0);
     else
         (version == 1) ? avio_wb64(pb, duration) : avio_wb32(pb, duration);
 
@@ -1771,7 +1777,7 @@ static int mov_write_trak_tag(AVIOContext *pb, MOVMuxContext *mov,
     }
     if (track->tref_tag)
         mov_write_tref_tag(pb, track);
-    mov_write_mdia_tag(pb, track);
+    mov_write_mdia_tag(pb, mov, track);
     if (track->mode == MODE_PSP)
         mov_write_uuid_tag_psp(pb, track); // PSP Movies require this uuid box
     if (track->tag == MKTAG('r','t','p',' '))