From 8502e50377c4e19ebb0f2d070cb5b415dc695901 Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Fri, 13 Aug 2010 02:13:03 +0000 Subject: Hopefully fix dropped MIDI notes on loop. Fixes #3133. git-svn-id: svn://localhost/ardour2/branches/3.0@7613 d708f5d6-7413-0410-9779-e7cbd77b26cf --- libs/ardour/midi_ring_buffer.cc | 46 ++++++++++++++++++++++++++++++++++------- 1 file changed, 39 insertions(+), 7 deletions(-) (limited to 'libs/ardour/midi_ring_buffer.cc') diff --git a/libs/ardour/midi_ring_buffer.cc b/libs/ardour/midi_ring_buffer.cc index 2999621b70..4c89cbcf4c 100644 --- a/libs/ardour/midi_ring_buffer.cc +++ b/libs/ardour/midi_ring_buffer.cc @@ -44,16 +44,44 @@ MidiRingBuffer::read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes Evoral::EventType ev_type; uint32_t ev_size; + /* If we see the end of a loop during this read, we must write the events after it + to the MidiBuffer with adjusted times. The situation is as follows: + + session frames-----------------------------> + + | | | + start_of_loop start end_of_loop + + The MidiDiskstream::read method which will have happened before this checks for + loops ending, and helpfully inserts a magic LoopEvent into the ringbuffer. After this, + the MidiDiskstream continues to write events with their proper session frame times, + so after the LoopEvent event times will go backwards (ie non-monotonically). + + Once we hit end_of_loop, we need to fake it to make it look as though the loop has been + immediately repeated. Say that an event E after the end_of_loop in the ringbuffer + has time E_t, which is a time in session frames. Its offset from the start + of the loop will be E_t - start_of_loop. Its `faked' time will therefore be + end_of_loop + E_t - start_of_loop. And so its port-buffer-relative time (for + writing to the MidiBuffer) will be end_of_loop + E_t - start_of_loop - start. + + The subtraction of start is already taken care of, so if we see a LoopEvent, we'll + set up loop_offset to equal end_of_loop - start_of_loop, so that given an event + time E_t in the ringbuffer we can get the port-buffer-relative time as + E_t + offset - start. + */ + + frameoffset_t loop_offset = 0; + size_t count = 0; while (this->read_space() >= sizeof(T) + sizeof(Evoral::EventType) + sizeof(uint32_t)) { this->full_peek(sizeof(T), (uint8_t*)&ev_time); - if (ev_time >= end) { + if (ev_time + loop_offset >= end) { DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB event @ %1 past end @ %2\n", ev_time, end)); break; - } else if (ev_time < start) { + } else if (ev_time + loop_offset < start) { DEBUG_TRACE (DEBUG::MidiDiskstreamIO, string_compose ("MRB event @ %1 before start @ %2\n", ev_time, start)); break; } else { @@ -68,15 +96,18 @@ MidiRingBuffer::read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes // This event marks a loop end (i.e. the next event's timestamp will be non-monotonic) if (ev_type == LoopEventType) { - /*ev_time -= start; - ev_time += offset;*/ cerr << "MRB loop boundary @ " << ev_time << endl; + + assert (ev_size == sizeof (nframes_t)); + nframes_t loop_start; + read_contents (ev_size, (uint8_t *) &loop_start); - // Return without reading data or writing to buffer (loop events have no data) - // FIXME: This is not correct, loses events after the loop this cycle - return count + 1; + loop_offset = ev_time - loop_start; + continue; } + ev_time += loop_offset; + uint8_t status; success = this->full_peek(sizeof(uint8_t), &status); assert(success); // If this failed, buffer is corrupt, all hope is lost @@ -92,6 +123,7 @@ MidiRingBuffer::read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes } assert(ev_time >= start); + ev_time -= start; ev_time += offset; -- cgit v1.2.3