prepare LTC File Reader

1 files changed, 199 insertions, 0 deletions

diff --git a/libs/ardour/ltc_file_reader.cc b/libs/ardour/ltc_file_reader.cc
new file mode 100644
index 0000000000..5f68a2d5ce
--- /dev/null
+++ b/libs/ardour/ltc_file_reader.cc
@@ -0,0 +1,199 @@
+/*
+    Copyright (C) 2015 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 <fcntl.h>
+#include <sys/stat.h>
+
+#include <glibmm.h>
+#include <assert.h>
+
+#include "pbd/error.h"
+#include "pbd/failed_constructor.h"
+
+#include "timecode/time.h"
+#include "ardour/ltc_file_reader.h"
+
+#include "i18n.h"
+
+using namespace std;
+using namespace ARDOUR;
+using namespace PBD;
+using std::string;
+
+#define BUFFER_SIZE 1024 // audio chunk size
+
+LTCFileReader::LTCFileReader (std::string path, double expected_fps, LTC_TV_STANDARD tv_standard)
+	: _path (path)
+	, _expected_fps (expected_fps)
+	, _ltc_tv_standard (tv_standard)
+	, _sndfile (0)
+	, _interleaved_audio_buffer (0)
+	, _frames_decoded (0)
+	, _samples_read (0)
+{
+	memset (&_info, 0, sizeof (_info));
+        assert (Glib::file_test (_path, Glib::FILE_TEST_EXISTS));
+
+	if (open ()) {
+		throw failed_constructor ();
+	}
+
+	const int apv = rintf (_info.samplerate / _expected_fps);
+	decoder = ltc_decoder_create (apv, 8); // must be able to hold frmes for BUFFER_SIZE
+
+#if 0 // TODO allow to auto-detect
+	if (expected_fps == 25.0) {
+		_ltc_tv_standard = LTC_TV_625_50;
+	}
+	else if (expected_fps == 30.0) {
+		_ltc_tv_standard = LTC_TV_525_60;
+	}
+	else {
+		_ltc_tv_standard = LTC_TV_FILM_24;
+	}
+#endif
+}
+
+LTCFileReader::~LTCFileReader ()
+{
+	close ();
+	ltc_decoder_free (decoder);
+	free (_interleaved_audio_buffer);
+}
+
+int
+LTCFileReader::open ()
+{
+	if (_sndfile) {
+		return 0;
+	}
+
+#ifdef PLATFORM_WINDOWS
+	int fd = g_open (_path.c_str (), O_RDONLY, 0444);
+#else
+	int fd = ::open (_path.c_str (), O_RDONLY, 0444);
+#endif
+	if (fd == -1) {
+		error << string_compose (_("LTCFileReader: cannot open file \"%1\""), _path) << endmsg;
+		return -1;
+	}
+
+	_sndfile = sf_open_fd (fd, SFM_READ, &_info, true);
+
+	if (_sndfile == 0) {
+		char errbuf[1024];
+		sf_error_str (0, errbuf, sizeof (errbuf) - 1);
+		error << string_compose (_("LTCFileReader: cannot open file \"%1\" (%3)"), _path, errbuf) << endmsg;
+		return -1;
+	}
+	if (_info.frames == 0 || _info.channels < 1) {
+		error << string_compose (_("LTCFileReader: \"%1\" is an empty audio file"), _path) << endmsg;
+		return -1;
+	}
+	_interleaved_audio_buffer = (float*) calloc (_info.channels * BUFFER_SIZE, sizeof (float));
+	return 0;
+}
+
+void
+LTCFileReader::close ()
+{
+	if (_sndfile) {
+		sf_close (_sndfile);
+		_sndfile = 0;
+	}
+}
+
+std::vector<LTCFileReader::LTCMap>
+LTCFileReader::read_ltc (uint32_t channel, uint32_t max_frames)
+{
+	std::vector<LTCFileReader::LTCMap> rv;
+	ltcsnd_sample_t sound[BUFFER_SIZE];
+	LTCFrameExt frame;
+
+	const uint32_t channels = _info.channels;
+	if (channel >= channels) {
+		warning << _("LTCFileReader:: invalid audio channel selected") << endmsg;
+		return rv;
+	}
+
+	while (1) {
+		int64_t n = sf_readf_float (_sndfile, _interleaved_audio_buffer, BUFFER_SIZE);
+		if (n <= 0) {
+			break;
+		}
+
+		// convert audio to 8bit unsigned
+		for (int64_t i = 0; i < n; ++i) {
+			sound [i]= 128 + _interleaved_audio_buffer[channels * i + channel] * 127;
+		}
+
+		ltc_decoder_write (decoder, sound, n, _samples_read);
+
+		while (ltc_decoder_read (decoder, &frame)) {
+			SMPTETimecode stime;
+			++_frames_decoded;
+
+			ltc_frame_to_time (&stime, &frame.ltc, /*use_date*/ 0);
+
+			// convert Timecode to samples @ audio-file rate
+			Timecode::Time timecode (_expected_fps);
+			timecode.hours   = stime.hours;
+			timecode.minutes = stime.mins;
+			timecode.seconds = stime.secs;
+			timecode.frames  = stime.frame;
+
+			int64_t sample = 0;
+			Timecode::timecode_to_sample (
+					timecode, sample, false, false,
+					_info.samplerate,
+					0, 0, 0);
+
+			// align LTC frame relative to video-frame
+			sample -= ltc_frame_alignment (
+					_info.samplerate / _expected_fps,
+					_ltc_tv_standard);
+
+			// convert to seconds (session can use session-rate)
+			double fp_sec = frame.off_start / (double) _info.samplerate;
+			double tc_sec = sample / (double) _info.samplerate;
+			rv.push_back (LTCMap (fp_sec, tc_sec));
+
+#if 0 // DEBUG
+			printf("LTC %02d:%02d:%02d:%02d @%9lld -> %9lld -> %fsec\n",
+					stime.hours,
+					stime.mins,
+					stime.secs,
+					stime.frame,
+					frame.off_start,
+					sample,
+					tc_sec);
+#endif
+		}
+
+		if (n > 0) {
+			_samples_read += n;
+		}
+
+		if (max_frames > 0 && rv.size () >= max_frames) {
+			break;
+		}
+
+	}
+
+	return rv;
+}