From 5fbcd0aa67ea07d06ece6a14a8c8bbee4e79f5ad Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Wed, 12 Apr 2017 22:52:53 +0200
Subject: [PATCH] MPEG TS reader: require five consecutive, identical AAC
 headers for track type detection

Using only a single one may lead to false positives and consequently
to wrong track parameters, especially if the file was cut at an
arbitrary position.

Fixes the audio-related part of #1938.
---
 NEWS.md                                                     | 4 ++++
 src/input/r_mpeg_ts.cpp                                     | 6 +++++-
 tests/results.txt                                           | 1 +
 .../test-592mpeg_ts_aac_wrong_track_parameters_detected.rb  | 5 +++++
 4 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100755 tests/test-592mpeg_ts_aac_wrong_track_parameters_detected.rb

diff --git a/NEWS.md b/NEWS.md
index de25b8d66..23574700c 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -41,6 +41,10 @@
   only the arrays actually present are parsed, and they can be in any order.
   This fixes mkvinfo's output for Matroska files created from files such as
   the one from #1938.
+* mkvmerge: MPEG TS reader, AAC: mkvmerge will now require five consecutive
+  AAC headers with identical parameters before track type determination is
+  considered valid. This avoids false positives and consequently wrong track
+  parameters. Fixes the audio-related part of #1938.
 
 ## Build system changes
 
diff --git a/src/input/r_mpeg_ts.cpp b/src/input/r_mpeg_ts.cpp
index 1499f591f..118be5771 100644
--- a/src/input/r_mpeg_ts.cpp
+++ b/src/input/r_mpeg_ts.cpp
@@ -332,8 +332,12 @@ int
 track_c::new_stream_a_aac() {
   add_pes_payload_to_probe_data();
 
+  auto pos = aac::parser_c::find_consecutive_frames(m_probe_data->get_buffer(), m_probe_data->get_size(), 5);
+  if (pos == -1)
+    return FILE_STATUS_MOREDATA;
+
   auto parser = aac::parser_c{};
-  parser.add_bytes(m_probe_data->get_buffer(), m_probe_data->get_size());
+  parser.add_bytes(m_probe_data->get_buffer() + pos, m_probe_data->get_size() - pos);
   if (!parser.frames_available() || !parser.headers_parsed())
     return FILE_STATUS_MOREDATA;
 
diff --git a/tests/results.txt b/tests/results.txt
index 402e03533..566d79636 100644
--- a/tests/results.txt
+++ b/tests/results.txt
@@ -437,3 +437,4 @@ T_588h265_must_copy_bitstream_restriction_info_in_vui_parameters:73adcf66e93a909
 T_589h264_forcing_default_duration_in_fields_with_source_matroska:57ec2c6f2b5f526a0bc0ae4b7d58a7fc-40000000+40000000+true-21388568453e93db9c2d8f57af26eb0b-20000000+20000000+true-6122f1005d1f64f9958f275220251ed9-30000000+30000000+true-6ee9a2e29ac6cd451bb971daf7b3a41e-60000000+60000000+true-205658c0f0458073f94f06a6b300ebb0-20000000+20000000+true:passed:20170331-165013:0.244234938
 T_590invalid_track_language_elements:39273b8f3b06c67c444c698d4c206847-fbb7ad6e65f0d85cacefd7765605757a-5193400637dc65f4028be97aea853e4b:passed:20170404-191832:0.036965692
 T_591hevc_wrong_number_of_parameter_sets:cc0ff46884d832c3b7234136f963bc39:passed:20170412-165246:0.341087191
+T_592mpeg_ts_aac_wrong_track_parameters_detected:25116993128e73fe9251dc7161ae8030:passed:20170412-225238:0.044257474
diff --git a/tests/test-592mpeg_ts_aac_wrong_track_parameters_detected.rb b/tests/test-592mpeg_ts_aac_wrong_track_parameters_detected.rb
new file mode 100755
index 000000000..08bc440a3
--- /dev/null
+++ b/tests/test-592mpeg_ts_aac_wrong_track_parameters_detected.rb
@@ -0,0 +1,5 @@
+#!/usr/bin/ruby -w
+
+# T_592mpeg_ts_aac_wrong_track_parameters_detected
+describe "mkvmerge / MPEG TS, AAC: false positive during AAC header detection leading to wrong track parameters"
+test_merge "data/h265/wrong_number_of_parameter_sets_in_hevcc.ts", :args => "--no-video"