so i tried to instrument cingg to see if  she does any unaligned access

 

 

I added

 

 

diff --git a/cinelerra-5.1/guicast/Makefile b/cinelerra-5.1/guicast/Makefile

index 04d5a2e5..b724c668 100644

--- a/cinelerra-5.1/guicast/Makefile

+++ b/cinelerra-5.1/guicast/Makefile

@@ -116,6 +116,7 @@ UTILS = $(OBJDIR)/bootstrap $(OBJDIR)/pngtoh $(OBJDIR)/pngto

raw

 BCXFER = xfer/$(OBJDIR)/xfer.stamp

 

 CFLAGS += $(static_incs)

+CFLAGS += -Wall -fsanitize=alignment

 

 $(shell echo $(CFLAGS) > $(OBJDIR)/c_flags)

 $(shell echo $(OBJS) > $(OBJDIR)/objs)

 

 

and same -fsanitize=alignment to LDFLAGS env. variable before make.

On 4 different systems I was only able to include in guicast/Makefile, the CFLAGS += $(-fsanitize=alignment) and set the LDFLAGS environment variable to -fsanitize=alignment in order to compile.  But when I ran bin/cin I never got any errors of the type "bctheme.C:458:15: runtime error: load of misaligned address".  This was Fedora 32, Ubuntu 16, Debian 32-bit 9.1, and Debian 11.0.  I only loaded a file, played a little of it, and added a plugin as a test (maybe there was something in particular I should have tried?)

 

so patch below fixes this error.

 

Can you please test it on various arches and distros?

 

 

diff --git a/cinelerra-5.1/guicast/bctheme.C b/cinelerra-5.1/guicast/bctheme.C

index 1ec64c7f..9addf9f7 100644

--- a/cinelerra-5.1/guicast/bctheme.C

+++ b/cinelerra-5.1/guicast/bctheme.C

@@ -455,7 +455,10 @@ void BC_Theme::overlay(VFrame *dst, VFrame *src, int in_x1, int in_x2, int shift

 

 void BC_Theme::set_data(unsigned char *ptr)

 {

-       int hdr_sz = *(int*)ptr - sizeof(int);

+       //int hdr_sz = *(int*)ptr - sizeof(int);

+       int hdr_sz = 0;

+       memcpy(&hdr_sz, ptr, sizeof(int));

+       hdr_sz -= sizeof(int);

        unsigned char *cp = ptr + sizeof(int);

        unsigned char *dp = cp + hdr_sz;

        int start_item = images.size();

lines 7-28/28 (END)

Next I added the above patch, and all 4 systems compiled and ran the same limited set of commands to load and play a video file.  So it seems OK to check into GIT.  Just to verify, only the bctheme.C patch should be checked in - right?