MP4: Get duration from mvhd if not present in mdhd (taglib#1165)

ufleisch · Nov 4, 2023 · 4d19420 · 4d19420
1 parent 70b4ce7
commit 4d19420
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Showing 2 changed files with 34 additions and 0 deletions.
diff --git a/taglib/mp4/mp4properties.cpp b/taglib/mp4/mp4properties.cpp
@@ -184,6 +184,17 @@ MP4::Properties::read(File *file, Atoms *atoms)
  unit = data.toUInt(20U);
  length = data.toUInt(24U);
  }
+ if(length == 0) {
+ // No length found in the media header (mdhd), try the movie header (mvhd)
+ if(MP4::Atom *mvhd = moov->find("mvhd")) {
+ file->seek(mvhd->offset);
+ data = file->readBlock(mvhd->length);
+ if(data.size() >= 24 + 4) {
+ unit = data.toUInt(20U);
+ length = data.toUInt(24U);
+ }
+ }
+ }
  if(unit > 0 && length > 0)
  d->length = static_cast<int>(length * 1000.0 / unit + 0.5);
 

diff --git a/tests/test_mp4.cpp b/tests/test_mp4.cpp
@@ -47,6 +47,7 @@ class TestMP4 : public CppUnit::TestFixture
  CPPUNIT_TEST(testPropertiesAACWithoutBitrate);
  CPPUNIT_TEST(testPropertiesALAC);
  CPPUNIT_TEST(testPropertiesALACWithoutBitrate);
+ CPPUNIT_TEST(testPropertiesAACWithoutLength);
  CPPUNIT_TEST(testPropertiesM4V);
  CPPUNIT_TEST(testFreeForm);
  CPPUNIT_TEST(testCheckValid);
@@ -144,6 +145,28 @@ class TestMP4 : public CppUnit::TestFixture
  CPPUNIT_ASSERT_EQUAL(MP4::Properties::ALAC, f.audioProperties()->codec());
  }
 
+ void testPropertiesAACWithoutLength()
+ {
+ ByteVector m4aData = PlainFile(TEST_FILE_PATH_C("no-tags.m4a")).readAll();
+ CPPUNIT_ASSERT_EQUAL(2898U, m4aData.size());
+ CPPUNIT_ASSERT_EQUAL(ByteVector("mdhd"), m4aData.mid(1749, 4));
+ // Set the length to zero
+ for (int offset = 1769; offset < 1773; ++offset) {
+ m4aData[offset] = 0;
+ }
+ ByteVectorStream m4aStream(m4aData);
+ MP4::File f(&m4aStream);
+ CPPUNIT_ASSERT(f.audioProperties());
+ CPPUNIT_ASSERT_EQUAL(3, f.audioProperties()->lengthInSeconds());
+ CPPUNIT_ASSERT_EQUAL(3707, f.audioProperties()->lengthInMilliseconds());
+ CPPUNIT_ASSERT_EQUAL(3, f.audioProperties()->bitrate());
+ CPPUNIT_ASSERT_EQUAL(2, f.audioProperties()->channels());
+ CPPUNIT_ASSERT_EQUAL(44100, f.audioProperties()->sampleRate());
+ CPPUNIT_ASSERT_EQUAL(16, f.audioProperties()->bitsPerSample());
+ CPPUNIT_ASSERT_EQUAL(false, f.audioProperties()->isEncrypted());
+ CPPUNIT_ASSERT_EQUAL(MP4::Properties::AAC, f.audioProperties()->codec());
+ }
+
  void testPropertiesM4V()
  {
  MP4::File f(TEST_FILE_PATH_C("blank_video.m4v"));