spa: ffmpeg: remove libavformat dependency

`av_register_all()` is the only thing used from libavformat,
but that doesn't seem to be needed for codec enumeration,
so remove it, and call `avcodec_register_all()` instead
when libavcodec < 58.10.100.

spa/meson.build

@@ -25,7 +25,6 @@ if not get_option('spa-plugins').disabled()
   aptx_dep = dependency('libopenaptx', version : '< 0.2.1', required : get_option('bluez5-codec-aptx'))
   fdk_aac_dep = dependency('fdk-aac', required : get_option('bluez5-codec-aac'))
   avcodec_dep = dependency('libavcodec', required: get_option('ffmpeg'))
-  avformat_dep = dependency('libavformat', required: get_option('ffmpeg'))
   jack_dep = dependency('jack', version : '>= 1.9.10', required: get_option('jack'))
   vulkan_dep = dependency('vulkan', disabler : true, version : '>= 1.1.69', required: get_option('vulkan'))
   vulkan_headers = cc.has_header('vulkan/vulkan.h', dependencies : vulkan_dep)

spa/plugins/ffmpeg/ffmpeg.c

@@ -29,7 +29,6 @@
 #include <spa/node/node.h>
 
 #include <libavcodec/avcodec.h>
-#include <libavformat/avformat.h>
 
 int spa_ffmpeg_dec_init(struct spa_handle *handle, const struct spa_dict *info,
 			const struct spa_support *support, uint32_t n_support);
@@ -90,9 +89,9 @@ int spa_handle_factory_enum(const struct spa_handle_factory **factory, uint32_t
 	static struct spa_handle_factory f;
 	static char name[128];
 
-  #if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(58, 9, 100)
-	av_register_all();
-  #endif
+#if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(58, 10, 100)
+	avcodec_register_all();
+#endif
 
 	if (*index == 0) {
 		c = av_codec_next(NULL);

spa/plugins/ffmpeg/meson.build

@@ -5,6 +5,6 @@ ffmpeg_sources = ['ffmpeg.c',
 ffmpeglib = shared_library('spa-ffmpeg',
                           ffmpeg_sources,
                           include_directories : [spa_inc],
-                          dependencies : [ avcodec_dep, avformat_dep ],
+                          dependencies : [avcodec_dep],
                           install : true,
 		          install_dir : spa_plugindir / 'ffmpeg')

spa/plugins/meson.build

@@ -14,7 +14,7 @@ if not get_option('audiotestsrc').disabled()
   subdir('audiotestsrc')
 endif
 subdir('bluez5')
-if avcodec_dep.found() and avformat_dep.found()
+if avcodec_dep.found()
   subdir('ffmpeg')
 endif
 if jack_dep.found()