Point fix: Align memory for libav sws buffer

The libav backend had a bug in software scaling. It set alignment
requirements for a buffer used for software scaling to 16 bytes, which
worked fine in past versions, but results in crashes nowadays with
videos that do not happen to naturally align as needed. This commit sets
the alignment to 64 byes, under the (unverified) assumption that ffmpeg
now uses vector instructions with that alignment requirement.

This change fixes the crash observed in #247 for the example file.

README.markdown

@@ -182,8 +182,9 @@ For some advanced uses of pqiv, take a look at these resouces:
 Changelog
 ---------
 
-pqiv 2.13.1
+pqiv 2.13.2
  * Revert to not adding `--browse` to desktop files (fixes #232)
+ * Fix crash for videos with unusual resolutions (fixes #247)
 
 pqiv 2.13
  * Fix `toggle_fullscreen(1/2)` behavior when already fullscreen

backends/libav.c

@@ -295,7 +295,7 @@ void file_type_libav_load(file_t *file, GInputStream *data, GError **error_point
 #if LIBAVUTIL_VERSION_INT < AV_VERSION_INT(55, 0, 0)
 	size_t num_bytes = avpicture_get_size(PIX_FMT_RGB32, file->width, file->height);
 #else
-	size_t num_bytes = av_image_get_buffer_size(AV_PIX_FMT_RGB32, file->width, file->height, 16);
+	size_t num_bytes = av_image_get_buffer_size(AV_PIX_FMT_RGB32, file->width, file->height, 64);
 #endif
 	private->buffer = (uint8_t *)g_malloc(num_bytes * sizeof(uint8_t));
 

pqiv.1

@@ -1,5 +1,5 @@
 .\" vim:filetype=groff
-.TH pqiv 1 "March 2024" "2.13.1"
+.TH pqiv 1 "March 2024" "2.13.2"
 .SH NAME
 pqiv \- powerful quick image viewer
 .\"

pqiv.h

@@ -29,7 +29,7 @@
 #include "lib/bostree.h"
 
 #ifndef PQIV_VERSION
-#define PQIV_VERSION "2.13.1"
+#define PQIV_VERSION "2.13.2"
 #endif
 
 #define FILE_FLAGS_ANIMATION      (guint)(1)