media-playback: Unbuffered Media Source

When using an IP camera on a local network, we wanted to minimize
delay. In order to achieve minimum delay, we allowed Media Source to
set BufferingMB to 0, and when it is 0, also enable AVFMT_FLAG_NOBUFFER
in the AVFormatContext flags.

deps/media-playback/media-playback/media.c

@@ -585,6 +585,9 @@ static bool init_avformat(mp_media_t *m)
 		av_dict_set_int(&opts, "buffer_size", m->buffering, 0);
 
 	m->fmt = avformat_alloc_context();
+	if (m->buffering == 0) {
+		m->fmt->flags |= AVFMT_FLAG_NOBUFFER;
+	}
 	if (!m->is_local_file) {
 		m->fmt->interrupt_callback.callback = interrupt_callback;
 		m->fmt->interrupt_callback.opaque = m;

plugins/obs-ffmpeg/obs-ffmpeg-source.c

@@ -163,7 +163,7 @@ static obs_properties_t *ffmpeg_source_getproperties(void *data)
 				obs_module_text("RestartWhenActivated"));
 
 	prop = obs_properties_add_int_slider(props, "buffering_mb",
-					     obs_module_text("BufferingMB"), 1,
+					     obs_module_text("BufferingMB"), 0,
 					     16, 1);
 	obs_property_int_set_suffix(prop, " MB");