towards a SRC source + resampling during audition

1 files changed, 160 insertions, 0 deletions

diff --git a/libs/ardour/srcfilesource.cc b/libs/ardour/srcfilesource.cc
new file mode 100644
index 0000000000..6af4aaa9d8
--- /dev/null
+++ b/libs/ardour/srcfilesource.cc
@@ -0,0 +1,160 @@
+/*
+    Copyright (C) 2014 Paul Davis
+    Written by: Robin Gareus <robin@gareus.org>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include "pbd/error.h"
+#include "pbd/failed_constructor.h"
+
+#include "ardour/audiofilesource.h"
+#include "ardour/debug.h"
+#include "ardour/srcfilesource.h"
+
+#include "i18n.h"
+
+using namespace ARDOUR;
+using namespace PBD;
+
+/* see disk_io_chunk_frames */
+const uint32_t SrcFileSource::blocksize = 65536U;
+
+SrcFileSource::SrcFileSource (Session& s, boost::shared_ptr<AudioFileSource> src, SrcQuality srcq)
+	: Source(s, DataType::AUDIO, src->name(), Flag (src->flags() & ~(Writable|Removable|RemovableIfEmpty|RemoveAtDestroy)))
+	, AudioFileSource (s, src->path(), Flag (src->flags() & ~(Writable|Removable|RemovableIfEmpty|RemoveAtDestroy)))
+	, _source (src)
+	, _src_state (0)
+	, _source_position(0)
+	, _target_position(0)
+	, _fract_position(0)
+{
+	assert(_source->n_channels() == 1);
+
+	int src_type = SRC_SINC_BEST_QUALITY;
+
+	switch (srcq) {
+		case SrcBest:
+			src_type = SRC_SINC_BEST_QUALITY;
+			break;
+		case SrcGood:
+			src_type = SRC_SINC_MEDIUM_QUALITY;
+			break;
+		case SrcQuick:
+			src_type = SRC_SINC_FASTEST;
+			break;
+		case SrcFast:
+			src_type = SRC_ZERO_ORDER_HOLD;
+			break;
+		case SrcFastest:
+			src_type = SRC_LINEAR;
+			break;
+	}
+
+
+	_ratio = s.nominal_frame_rate() / _source->sample_rate();
+	_src_data.src_ratio = _ratio;
+
+	src_buffer_size = ceil((double)blocksize / _ratio) + 2;
+	_src_buffer = new float[src_buffer_size];
+
+	int err;
+	if ((_src_state = src_new (src_type, 1, &err)) == 0) {
+		error << string_compose(_("Import: src_new() failed : %1"), src_strerror (err)) << endmsg ;
+		throw failed_constructor ();
+	}
+}
+
+SrcFileSource::~SrcFileSource ()
+{
+	DEBUG_TRACE (DEBUG::AudioPlayback, "SrcFileSource::~SrcFileSource\n");
+	_src_state = src_delete (_src_state) ;
+	delete [] _src_buffer;
+}
+
+framecnt_t
+SrcFileSource::read_unlocked (Sample *dst, framepos_t start, framecnt_t cnt) const
+{
+	int err;
+	const double srccnt = cnt / _ratio;
+
+	if (_target_position != start) {
+		DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("SRC: reset %1 -> %2\n", _target_position, start));
+		src_reset(_src_state);
+		_fract_position = 0;
+		_source_position = start / _ratio;
+		_target_position = start;
+	}
+
+	const framecnt_t scnt = ceilf(srccnt - _fract_position);
+	_fract_position += (scnt - srccnt);
+
+#ifndef NDEBUG
+	if (scnt >= src_buffer_size) {
+		DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("SRC: CRASH AHEAD :)  %1 >= %2 (fract=%3, cnt=%4)\n",
+					scnt, src_buffer_size, _fract_position, cnt));
+	}
+#endif
+	assert(scnt < src_buffer_size);
+
+	_src_data.input_frames = _source->read (_src_buffer, _source_position, scnt);
+
+	if ((framecnt_t) _src_data.input_frames < scnt
+			|| _source_position + scnt >= _source->length(0)) {
+		_src_data.end_of_input = true;
+		_target_position += _src_data.input_frames * _ratio;
+		DEBUG_TRACE (DEBUG::AudioPlayback, "SRC: END OF INPUT\n");
+	} else {
+		_src_data.end_of_input = false;
+		_target_position += cnt;
+	}
+
+	_src_data.output_frames = cnt;
+	_src_data.data_in = _src_buffer;
+	_src_data.data_out = dst;
+
+	if (_src_data.end_of_input) {
+		_src_data.output_frames = std::min ((long)floor(_src_data.input_frames * _ratio), _src_data.output_frames);
+	}
+
+
+	if ((err = src_process (_src_state, &_src_data))) {
+		error << string_compose(_("SrcFileSource: %1"), src_strerror (err)) << endmsg ;
+		return 0;
+	}
+
+	if (_src_data.end_of_input && _src_data.output_frames_gen <= 0) {
+		return 0;
+	}
+
+	_source_position += _src_data.input_frames_used;
+
+	framepos_t saved_target = _target_position;
+	framecnt_t generated = _src_data.output_frames_gen;
+
+	while (generated < cnt) {
+		DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("SRC: recurse for %1 samples\n",  cnt - generated));
+		framecnt_t g = read_unlocked(dst + generated, _target_position, cnt - generated);
+		generated += g;
+		if (g == 0) break;
+	}
+	_target_position = saved_target;
+
+	DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("SRC: in: %1-> want: %2 || got: %3 total: %4\n",
+				_src_data.input_frames, _src_data.output_frames, _src_data.output_frames_gen, generated));
+
+	return generated;
+}