From e1b74c6e6f5b892bfb1ff8caa1f7660da290285d Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Sat, 9 Jun 2018 12:05:18 +0200
Subject: [PATCH] DVB subs: don't fix 4 byte CodecPrivate before identification

The identification should show what's actually there in the file, not
the fixed-up data.
---
 src/input/r_matroska.cpp                      | 32 +++++++++++--------
 src/input/r_matroska.h                        |  2 ++
 tests/results.txt                             |  2 +-
 .../test-583dvbsub_four_bytes_codecprivate.rb | 10 ++++--
 4 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/src/input/r_matroska.cpp b/src/input/r_matroska.cpp
index 406677f2a..0b58b425e 100644
--- a/src/input/r_matroska.cpp
+++ b/src/input/r_matroska.cpp
@@ -698,14 +698,6 @@ kax_reader_c::verify_dvb_subtitle_track(kax_track_t *t) {
     return false;
   }
 
-  if (t->private_data->get_size() == 4) {
-    // The subtitling type byte is missing. Add it. From ETSI EN 300 468 table 26:
-    // 0x10 = DVB subtitles (normal) with no monitor aspect ratio criticality
-
-    t->private_data->resize(5);
-    t->private_data->get_buffer()[4] = 0x10;
-  }
-
   return true;
 }
 
@@ -1977,6 +1969,22 @@ kax_reader_c::create_audio_packetizer(kax_track_t *t,
   t->handle_packetizer_codec_delay();
 }
 
+void
+kax_reader_c::create_dvbsub_subtitle_packetizer(kax_track_t &t,
+                                                track_info_c &nti) {
+  if (t.private_data->get_size() == 4) {
+    // The subtitling type byte is missing. Add it. From ETSI EN 300 468 table 26:
+    // 0x10 = DVB subtitles (normal) with no monitor aspect ratio criticality
+
+    t.private_data->resize(5);
+    t.private_data->get_buffer()[4] = 0x10;
+  }
+
+  set_track_packetizer(&t, new dvbsub_packetizer_c(this, nti, t.private_data));
+  show_packetizer_info(t.tnum, t.ptzr_ptr);
+  t.sub_type = 'p';
+}
+
 void
 kax_reader_c::create_subtitle_packetizer(kax_track_t *t,
                                          track_info_c &nti) {
@@ -1986,12 +1994,10 @@ kax_reader_c::create_subtitle_packetizer(kax_track_t *t,
 
     t->sub_type = 'v';
 
-  } else if (t->codec.is(codec_c::type_e::S_DVBSUB)) {
-    set_track_packetizer(t, new dvbsub_packetizer_c(this, nti, t->private_data));
-    show_packetizer_info(t->tnum, t->ptzr_ptr);
-    t->sub_type = 'p';
+  } else if (t->codec.is(codec_c::type_e::S_DVBSUB))
+    create_dvbsub_subtitle_packetizer(*t, nti);
 
-  } else if (t->codec.is(codec_c::type_e::S_WEBVTT)) {
+  else if (t->codec.is(codec_c::type_e::S_WEBVTT)) {
     set_track_packetizer(t, new webvtt_packetizer_c(this, nti));
     show_packetizer_info(t->tnum, t->ptzr_ptr);
 
diff --git a/src/input/r_matroska.h b/src/input/r_matroska.h
index 09b364931..34f5de6f1 100644
--- a/src/input/r_matroska.h
+++ b/src/input/r_matroska.h
@@ -314,6 +314,8 @@ protected:
   virtual void create_avc_video_packetizer(kax_track_t *t, track_info_c &nti);
   virtual void create_avc_es_video_packetizer(kax_track_t *t, track_info_c &nti);
 
+  virtual void create_dvbsub_subtitle_packetizer(kax_track_t &t, track_info_c &nti);
+
   virtual void read_headers_info(mm_io_c *io, EbmlElement *l0, int64_t position);
   virtual void read_headers_info_writing_app(KaxWritingApp *&kwriting_app);
   virtual void read_headers_track_audio(kax_track_t *track, KaxTrackAudio *ktaudio);
diff --git a/tests/results.txt b/tests/results.txt
index 92490abb9..ca419712b 100644
--- a/tests/results.txt
+++ b/tests/results.txt
@@ -428,7 +428,7 @@ T_579vobsub_in_matroska_without_codecprivate:405065b599ed13549aed6f6a3a4d9a61-8b
 T_580mp4_dash_moof_after_moov_and_mdat:f1fff7b1ebacc42779b81a28a8419e22:passed:20170127-203233:0.04411854
 T_581mp4_multiple_moov_atoms:66936ba41652629cf1c65fc944016c19:passed:20170129-104017:0.104375064
 T_582reading_mp4_with_and_without_track_order:fedfd2e0b9c21c282c6c94ecb6787999-fedfd2e0b9c21c282c6c94ecb6787999:passed:20170211-173020:0.065096784
-T_583dvbsub_four_bytes_codecprivate:2eb500871b0eefccbf284c9a7b20fad9-60ea2bea10aedfc7b9e3281292bb63cb:passed:20170217-183748:0.078521662
+T_583dvbsub_four_bytes_codecprivate:4+4+4-351d2991cf139bb1fe6db31652f9da6f:passed:20170217-183748:0.078521662
 T_584ac_3_misdetected_as_mp3:true-8d0eb2c407a645f9925d3f0eca0f9e2a:passed:20170218-123152:0.369584022
 T_585h264_wrong_mapping_of_timestamps_to_frames:b029b516547274fa059f9cb467a15072:passed:20170318-172210:0.580192044
 T_586h265_invalid_default_display_window_in_sps_vui:d60a90e202c1fc45a8df995c9c3afc44:passed:20170319-185708:0.186032079
diff --git a/tests/test-583dvbsub_four_bytes_codecprivate.rb b/tests/test-583dvbsub_four_bytes_codecprivate.rb
index 8d8688122..8b047a850 100755
--- a/tests/test-583dvbsub_four_bytes_codecprivate.rb
+++ b/tests/test-583dvbsub_four_bytes_codecprivate.rb
@@ -5,5 +5,11 @@ describe "mkvmerge / DVB subtitles in Matroska with CodecPrivate missing the sub
 
 file = "data/subtitles/dvbsub/codecprivate_four_bytes.mkv"
 
-test_identify file
-test_merge file
+test "codec private length" do
+  identify_json(file)["tracks"].
+    select { |t| t["codec"] == "DVBSUB" }.
+    map    { |t| t["properties"]["codec_private_length"].to_s }.
+    join('+')
+end
+
+test_merge file, :args => "-A -D"