lossless transcode aborts

[white-haired-uncle]

• Platform:
  Linux mythbackend 6.5.0-35-generic #35~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue May 7 09:00:52 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
• MythTV version:

v35-Pre-331-g41b921c949

• Package version:

• Component:

mythtranscode

What steps will reproduce the bug?

See attached.

mythtranscode.txt

How often does it reproduce? Is there a required condition?

I've only tried two so far and it has been consistent.

What is the expected behaviour?

What do you see instead?

Additional information

[white-haired-uncle]

The error appears to be introduced in d4e6b3c. Works fine with previous commit, fails with d4e6b3c.

[ulmus-scott]

Try this:

diff --git a/mythtv/programs/mythtranscode/mpeg2fix.cpp b/mythtv/programs/mythtranscode/mpeg2fix.cpp
index 67cb340092..619d6cf97a 100644
--- a/mythtv/programs/mythtranscode/mpeg2fix.cpp
+++ b/mythtv/programs/mythtranscode/mpeg2fix.cpp
@@ -45,19 +45,6 @@ extern "C" {
 #define O_LARGEFILE 0
 #endif
 
-static void *my_malloc(unsigned size, [[maybe_unused]] mpeg2_alloc_t reason)
-{
-    if (size)
-    {
-#ifdef _WIN32
-        return _aligned_malloc( 64, size );
-#else
-        return aligned_alloc( 64, size );
-#endif
-    }
-    return nullptr;
-}
-
 static void my_av_print([[maybe_unused]] void *ptr,
                         int level, const char* fmt, va_list vl)
 {
@@ -266,7 +253,6 @@ MPEG2fixup::MPEG2fixup(const QString &inf, const QString &outf,
         m_useSecondary = true;
     }
 
-    mpeg2_malloc_hooks(my_malloc, nullptr);
     m_headerDecoder = mpeg2_init();
     m_imgDecoder = mpeg2_init();
 

@linuxdude42 aligned_alloc() requires size % alignment == 0 which the prior version did not. If that additional restriction was acceptable, free would need to be passed to mpeg2_malloc_hooks() instead of nullptr, otherwise libmpeg2 looks at the address prior to the one returned (which is a segmentation fault with aligned_alloc()) for a void* that points to the beginning of the allocated memory for use in free(). However, the previous version of my_malloc() is just a verbatim copy of what libmythmpeg2/alloc.c does if mpeg2_malloc_hooks() was not called, so we should just use the version from libmpeg2. (I don't know why my_malloc() ever existed since the version in libmpeg2 was first and neither have changed since then.)

[white-haired-uncle]

The above changes worked for me.

Thanks

[linuxdude42]

Thanks for the research, Scott.