Fix erractic timecode detection when extracting LTC from video
Some music using square waves can inadvertently be interpreted as valid LTC frame. However the encoded data is not a valid timecode, which can lead huge A/V offsets, or other issues.
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@ -38,7 +38,7 @@ public:
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void write (float const*, samplecnt_t n_samples, samplepos_t pos = -1);
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void write (float const*, samplecnt_t n_samples, samplepos_t pos = -1);
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void raw_write (ltcsnd_sample_t*, size_t, ltc_off_t);
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void raw_write (ltcsnd_sample_t*, size_t, ltc_off_t);
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samplepos_t read (uint32_t& hh, uint32_t& mm, uint32_t& ss, uint32_t& ff);
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samplepos_t read (uint32_t& hh, uint32_t& mm, uint32_t& ss, uint32_t& ff, samplecnt_t& len);
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private:
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private:
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LTCDecoder* _decoder;
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LTCDecoder* _decoder;
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@ -79,6 +79,7 @@ private:
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LTCReader* _reader;
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LTCReader* _reader;
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float* _interleaved_audio_buffer;
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float* _interleaved_audio_buffer;
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samplecnt_t _samples_read;
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samplecnt_t _samples_read;
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float _apv;
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};
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};
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@ -83,7 +83,7 @@ LTCReader::raw_write (ltcsnd_sample_t* buf, size_t size, ltc_off_t off)
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}
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}
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samplepos_t
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samplepos_t
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LTCReader::read (uint32_t& hh, uint32_t& mm, uint32_t& ss, uint32_t& ff)
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LTCReader::read (uint32_t& hh, uint32_t& mm, uint32_t& ss, uint32_t& ff, samplecnt_t& ll)
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{
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{
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LTCFrameExt ltc_frame;
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LTCFrameExt ltc_frame;
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if (0 == ltc_decoder_read (_decoder, <c_frame)) {
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if (0 == ltc_decoder_read (_decoder, <c_frame)) {
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@ -96,6 +96,8 @@ LTCReader::read (uint32_t& hh, uint32_t& mm, uint32_t& ss, uint32_t& ff)
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mm = stime.mins;
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mm = stime.mins;
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ss = stime.secs;
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ss = stime.secs;
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ff = stime.frame;
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ff = stime.frame;
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ll = ltc_frame.off_end - ltc_frame.off_start;
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return ltc_frame.off_start;
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return ltc_frame.off_start;
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}
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}
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@ -108,6 +110,7 @@ LTCFileReader::LTCFileReader (std::string path, double expected_fps, LTC_TV_STAN
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, _reader (0)
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, _reader (0)
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, _interleaved_audio_buffer (0)
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, _interleaved_audio_buffer (0)
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, _samples_read (0)
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, _samples_read (0)
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, _apv (1920)
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{
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{
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memset (&_info, 0, sizeof (_info));
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memset (&_info, 0, sizeof (_info));
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assert (Glib::file_test (_path, Glib::FILE_TEST_EXISTS));
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assert (Glib::file_test (_path, Glib::FILE_TEST_EXISTS));
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@ -116,7 +119,7 @@ LTCFileReader::LTCFileReader (std::string path, double expected_fps, LTC_TV_STAN
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throw failed_constructor ();
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throw failed_constructor ();
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}
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}
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const int apv = rintf (_info.samplerate / _expected_fps);
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_apv = _info.samplerate / _expected_fps;
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#if 0 // TODO allow to auto-detect
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#if 0 // TODO allow to auto-detect
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if (expected_fps == 25.0) {
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if (expected_fps == 25.0) {
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@ -129,7 +132,7 @@ LTCFileReader::LTCFileReader (std::string path, double expected_fps, LTC_TV_STAN
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_ltc_tv_standard = LTC_TV_FILM_24;
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_ltc_tv_standard = LTC_TV_FILM_24;
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}
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}
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#endif
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#endif
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_reader = new LTCReader (apv, _ltc_tv_standard);
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_reader = new LTCReader (rintf (_apv), _ltc_tv_standard);
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}
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}
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LTCFileReader::~LTCFileReader ()
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LTCFileReader::~LTCFileReader ()
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@ -208,8 +211,19 @@ LTCFileReader::read_ltc (uint32_t channel, uint32_t max_frames)
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Timecode::Time timecode (_expected_fps);
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Timecode::Time timecode (_expected_fps);
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samplepos_t off_start;
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samplepos_t off_start;
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samplecnt_t ltc_length;
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while ((off_start = _reader->read (timecode.hours, timecode.minutes, timecode.seconds, timecode.frames, ltc_length)) >= 0) {
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/* sanity check */
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if (timecode.hours > 23 || timecode.minutes > 60 || timecode.seconds > 60) {
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continue;
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}
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float speed = ltc_length / _apv;
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if (speed > 5 || speed < 0.2) {
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continue;
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}
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while ((off_start = _reader->read (timecode.hours, timecode.minutes, timecode.seconds, timecode.frames)) >= 0) {
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int64_t sample = 0;
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int64_t sample = 0;
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Timecode::timecode_to_sample (
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Timecode::timecode_to_sample (
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timecode, sample, false, false,
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timecode, sample, false, false,
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@ -28,7 +28,7 @@ function dsp_run (ins, outs, n_samples)
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local rv
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local rv
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repeat
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repeat
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local tc
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local tc
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rv, tc = ltc_reader:read (0, 0, 0, 0)
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rv, tc = ltc_reader:read (0, 0, 0, 0, 0)
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if rv >= 0 then
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if rv >= 0 then
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timeout = 0
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timeout = 0
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self:shmem():atomic_set_int (0, 1)
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self:shmem():atomic_set_int (0, 1)
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