From 9afc43b2096b915fc298e1719a040a4990245284 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Wed, 13 Jun 2018 17:57:20 +0200
Subject: [PATCH] HEVC/h.265 ES reader: clear parser's buffer after reading the
 headers
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After reading the headers, the file is read again from the
start. Therefore no data must be left in the parser's internal
buffers. That was the intention behind calling `flush()` - but that
isn't actually what flush does. Instead it tries to use the remaining
data in the buffers as a frame.

This is not only wrong, it can also fail and cause an exception to be
thrown. That in turn causes a failure when reading the headers — both
identification and muxing abort at that point.

This is the HEVC analog for what was fixed for AVC in #2325.
---
 NEWS.md                       | 3 +++
 src/common/hevc_es_parser.cpp | 7 +++++++
 src/common/hevc_es_parser.h   | 1 +
 src/input/r_hevc.cpp          | 5 ++---
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 6db2b19d9..fd42ec61b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -8,6 +8,9 @@
 * mkvmerge: AVC/h.264: fixed file identification failing for certain
   elementary streams due to internal buffers not being cleared properly. Fixes
   #2325.
+* mkvmerge: HEVC/h.265: fixed file identification failing for certain
+  elementary streams due to internal buffers not being cleared properly. This
+  is the HEVC analog to what was fixed for AVC in #2325.
 
 
 # Version 24.0.0 "Beyond The Pale" 2018-06-10
diff --git a/src/common/hevc_es_parser.cpp b/src/common/hevc_es_parser.cpp
index 558b1834d..ae6d934c0 100644
--- a/src/common/hevc_es_parser.cpp
+++ b/src/common/hevc_es_parser.cpp
@@ -192,6 +192,13 @@ es_parser_c::flush() {
   cleanup();
 }
 
+void
+es_parser_c::clear() {
+  m_unparsed_buffer.reset();
+  m_have_incomplete_frame = false;
+  m_parsed_position       = 0;
+}
+
 void
 es_parser_c::add_timestamp(int64_t timestamp) {
   m_provided_timestamps.emplace_back(timestamp, m_stream_position);
diff --git a/src/common/hevc_es_parser.h b/src/common/hevc_es_parser.h
index e421adc8e..09fc7218d 100644
--- a/src/common/hevc_es_parser.h
+++ b/src/common/hevc_es_parser.h
@@ -119,6 +119,7 @@ public:
   }
 
   void flush();
+  void clear();
 
   bool frame_available() {
     return !m_frames_out.empty();
diff --git a/src/input/r_hevc.cpp b/src/input/r_hevc.cpp
index 7c9fa36b4..0f9f3f7c7 100644
--- a/src/input/r_hevc.cpp
+++ b/src/input/r_hevc.cpp
@@ -89,14 +89,13 @@ hevc_es_reader_c::read_headers() {
         break;
     }
 
-    if (parser.headers_parsed())
-      parser.flush();
-
     m_width  = parser.get_width();
     m_height = parser.get_height();
 
     m_in->setFilePointer(0, seek_beginning);
 
+    parser.clear();
+
   } catch (...) {
     throw mtx::input::open_x();
   }