Add compatiblity for some older ffmpeg versions

plugins/obs-ffmpeg/obs-ffmpeg-aac.c

@@ -20,7 +20,9 @@
 #include <obs.h>
 
 #include <libavformat/avformat.h>
+
 #include "obs-ffmpeg-formats.h"
+#include "obs-ffmpeg-compat.h"
 
 struct aac_encoder {
 	obs_encoder_t    encoder;

plugins/obs-ffmpeg/obs-ffmpeg-compat.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <libavcodec/avcodec.h>
+
+/* LIBAVCODEC_VERSION_CHECK checks for the right version of libav and FFmpeg
+ * a is the major version
+ * b and c the minor and micro versions of libav
+ * d and e the minor and micro versions of FFmpeg */
+#define LIBAVCODEC_VERSION_CHECK( a, b, c, d, e ) \
+    ( (LIBAVCODEC_VERSION_MICRO <  100 && LIBAVCODEC_VERSION_INT >= AV_VERSION_INT( a, b, c ) ) || \
+      (LIBAVCODEC_VERSION_MICRO >= 100 && LIBAVCODEC_VERSION_INT >= AV_VERSION_INT( a, d, e ) ) )
+
+#if !LIBAVCODEC_VERSION_CHECK(54, 28, 0, 59, 100)
+# define avcodec_free_frame av_freep
+#endif
+
+#if LIBAVCODEC_VERSION_INT < 0x371c01
+# define av_frame_alloc avcodec_alloc_frame
+# define av_frame_unref avcodec_get_frame_defaults
+# define av_frame_free avcodec_free_frame
+#endif
+

plugins/obs-ffmpeg/obs-ffmpeg-output.c

@@ -27,6 +27,7 @@
 #include <libswscale/swscale.h>
 
 #include "obs-ffmpeg-formats.h"
+#include "obs-ffmpeg-compat.h"
 
 //#define OBS_FFMPEG_VIDEO_FORMAT VIDEO_FORMAT_I420
 #define OBS_FFMPEG_VIDEO_FORMAT VIDEO_FORMAT_NV12