From 14d7db97edabe9cc1fd28aa38976bd8d0b3b5724 Mon Sep 17 00:00:00 2001
From: Moritz Bunkus <moritz@bunkus.org>
Date: Sun, 24 Feb 2013 13:33:16 +0100
Subject: [PATCH] PS input: improve video type detection for MPEG-1/2 vs.
 AVC/h.264

Fixes #845.
---
 ChangeLog                                     |  3 ++
 src/input/r_mpeg_ps.cpp                       | 34 ++++++++++++++-----
 tests/results.txt                             |  1 +
 .../test-389mpeg1_in_ps_misdetected_as_avc.rb |  5 +++
 4 files changed, 35 insertions(+), 8 deletions(-)
 create mode 100644 tests/test-389mpeg1_in_ps_misdetected_as_avc.rb

diff --git a/ChangeLog b/ChangeLog
index b480f47cd..ea5cab146 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2013-02-24  Moritz Bunkus  <moritz@bunkus.org>
 
+        * mkvmerge: bug fix: Fixed mkvmerge sometimes mistakenly detecting
+        MPEG-1 video in MPEG program streams as AVC/h.264. Fixes #845.
+
         * mmg: new feature: When a playlist file (e.g. MPLS Blu-ray
         playlist) is added mmg can optionally scan all the other files in
         the directory that have the same extension and present the user
diff --git a/src/input/r_mpeg_ps.cpp b/src/input/r_mpeg_ps.cpp
index 6ceb41d69..114d88466 100644
--- a/src/input/r_mpeg_ps.cpp
+++ b/src/input/r_mpeg_ps.cpp
@@ -487,6 +487,24 @@ mpeg_ps_reader_c::new_stream_v_avc_or_mpeg_1_2(mpeg_ps_id_t id,
     uint64_t marker            = 0;
     int pos                    = 0;
 
+    while (4 > buffer.get_size()) {
+      if (!find_next_packet_for_id(id, PS_PROBE_SIZE))
+        throw false;
+
+      auto packet = parse_packet(id);
+      if (!packet)
+        continue;
+
+      buffer.add(packet.m_buffer->get_buffer(), packet.m_length);
+    }
+
+    marker = get_uint32_be(buffer.get_buffer());
+    if (NALU_START_CODE == marker) {
+      m_in->restore_pos();
+      new_stream_v_avc(id, buf, length, track);
+      return;
+    }
+
     while (1) {
       unsigned char *ptr = buffer.get_buffer();
       int buffer_size    = buffer.get_size();
@@ -521,13 +539,6 @@ mpeg_ps_reader_c::new_stream_v_avc_or_mpeg_1_2(mpeg_ps_id_t id,
               avc_access_unit_found = true;
               break;
           }
-
-          if (avc_seq_param_found && avc_pic_param_found && (avc_access_unit_found || avc_slice_found)) {
-            m_in->restore_pos();
-            new_stream_v_avc(id, buf, length, track);
-            return;
-          }
-
         }
 
         if (mpeg_is_start_code(marker)) {
@@ -551,7 +562,7 @@ mpeg_ps_reader_c::new_stream_v_avc_or_mpeg_1_2(mpeg_ps_id_t id,
       }
 
       if (!find_next_packet_for_id(id, PS_PROBE_SIZE))
-        throw false;
+        break;
 
       auto packet = parse_packet(id);
       if (!packet)
@@ -559,6 +570,13 @@ mpeg_ps_reader_c::new_stream_v_avc_or_mpeg_1_2(mpeg_ps_id_t id,
 
       buffer.add(packet.m_buffer->get_buffer(), packet.m_length);
     }
+
+    if (avc_seq_param_found && avc_pic_param_found && (avc_access_unit_found || avc_slice_found)) {
+      m_in->restore_pos();
+      new_stream_v_avc(id, buf, length, track);
+      return;
+    }
+
   } catch (...) {
   }
 
diff --git a/tests/results.txt b/tests/results.txt
index 2370e110d..faa8545a1 100644
--- a/tests/results.txt
+++ b/tests/results.txt
@@ -234,3 +234,4 @@ T_385split_parts_frames:14add8af7d016c048f0828708af04a86+c787a3d20fe2c26f7e0e031
 T_386flv_vp6f:a0ab8eb0dedf2c8c472e818794c2ad64:passed:20130121-223417:0.187881106
 T_387mp4_free_invalid_size:f3deb6abb3f60c0de606e166353a71b1:passed:20130216-003333:0.04107827
 T_388split_parts_and_chapters:e1bc3ec155ec33bca8eec967aceab25a-389c3bd6f8eca14fea4ef663a59b2e83-04fa29b52eb8d4962edf4f010548b375:passed:20130216-203522:0.690018077
+T_389mpeg1_in_ps_misdetected_as_avc:31ba2275cda1531973423ad509013fdb:passed:20130224-132738:1.205560654
diff --git a/tests/test-389mpeg1_in_ps_misdetected_as_avc.rb b/tests/test-389mpeg1_in_ps_misdetected_as_avc.rb
new file mode 100644
index 000000000..5e0af52f1
--- /dev/null
+++ b/tests/test-389mpeg1_in_ps_misdetected_as_avc.rb
@@ -0,0 +1,5 @@
+#!/usr/bin/ruby -w
+
+# T_389mpeg1_in_ps_misdetected_as_avc
+describe "mkvmerge / MPEG-1 in program stream misdetected as AVC"
+test_merge "data/mpeg12/mpeg1-misdetected-as-avc.mpg"