1Gst-LV2 Quickstart 2 3Dependencies: 4 5Lilv 0.6.6 <http://drobilla.net/software/lilv/> 6 7 8Features: 9 10The plugin wrapper support the following plugin features: 11http://lv2plug.in/ns/lv2core 12http://lv2plug.in/ns/ext/event 13http://lv2plug.in/ns/ext/port-groups 14 15and these host features: 16http://lv2plug.in/ns/ext/log 17http://lv2plug.in/ns/ext/urid 18 19Example Pipeline: 20 21Requires swh-lv2 <http://plugin.org.uk/releases/> 22 23gst-launch-1.0 -v filesrc location=/usr/share/sounds/login.wav ! wavparse ! audioconvert ! plugin-org-uk-swh-plugins-djFlanger ! audioconvert ! autoaudiosink 24(A longer wav will be a better example) 25 26gst-launch-1.0 plugin-org-uk-swh-plugins-analogueOsc num-buffers=100 wave=1 ! wavenc ! filesink location="/tmp/lv2.wav" 27 28Requires calf <http://calf.sourceforge.net/> 29 30GST_DEBUG="*:2,lv2:5" 31gst-launch-1.0 calf-sourceforge-net-plugins-Monosynth event-in="C-3" ! autoaudiosink 32gst-launch-1.0 calf-sourceforge-net-plugins-Monosynth event-in="C-3" name=ms ! autoaudiosink ms. ! fakesink 33gst-launch-1.0 calf-sourceforge-net-plugins-Organ event-in="C-3" name=s ! interleave name=i ! autoaudiosink s. ! i. 34 35 36TODO 37* make filters gap-aware 38* report latency 39 lilv_plugin_has_latency(), lilv_plugin_get_latency_port_index() 40* support more host features 41 GST_DEBUG="lv2:4" GST_DEBUG_FILE=/tmp/gst.log gst-inspect lv2 42 grep -o "needs host feature: .*$" /tmp/gst.log | sort | uniq -c | sort -n 43* make source elements useful 44 Most source elements use Atom port where they accept midi events. Since it is 45 full fledged midi, we should only ever use channel-0 and instead use multiple 46 instances 47 1) We could expose those as "audio/x-midi-event" sink pads, but then those are 48 not sources anymore. 49 2) We could expose those as properties using a new type like GST_FOURCC. If we 50 ignore "System Exclusive" messages, all other midi messages are 1-3 bytes. 51 We stuff the bytes right to left. E.g: the lowest byte is the status byte 52 3) We could use the GstBtNote enum + the toneconversion classes 53 https://www.midi.org/specifications/item/table-1-summary-of-midi-message 54 Open questions: 55 - with one property, we can't handle polyphony 56 - we can't query lv2 plugins for their polyphony :/ 57 58 If lv2 gets a polyphony extension it would be a single non-negative integer: 59 0: unbound, 1 monophonic, > 1 N-polyphonic 60 I've checked a few synths and they all have an upper limit. Still the way 61 voices work in trackers is not the same as they work in synths - e.g. in a 62 tracker one can play a note twice 63 64 Or we just play them monophonic and try to implement a polychildbin. The bin 65 takes a GstElement to be used as a voice. For each new voice it would create a 66 new instance and it uses a built-in mixer. Downside is that all properties 67 would be per voice. 68 69* example sources: 70 http://svn.drobilla.net/lad/trunk/lilv/utils/lv2info.c 71 http://svn.drobilla.net/lad/trunk/jalv/src/jalv.c 72