diff options
Diffstat (limited to 'src/sound_asset_writer.cc')
| -rw-r--r-- | src/sound_asset_writer.cc | 124 |
1 files changed, 115 insertions, 9 deletions
diff --git a/src/sound_asset_writer.cc b/src/sound_asset_writer.cc index 8df4d911..ff1d02c2 100644 --- a/src/sound_asset_writer.cc +++ b/src/sound_asset_writer.cc @@ -1,5 +1,5 @@ /* - Copyright (C) 2012-2014 Carl Hetherington <cth@carlh.net> + Copyright (C) 2012-2020 Carl Hetherington <cth@carlh.net> This file is part of libdcp. @@ -31,6 +31,7 @@ files in the program, then also delete it here. */ +#include "bitstream.h" #include "sound_asset_writer.h" #include "sound_asset.h" #include "exceptions.h" @@ -43,6 +44,8 @@ using std::min; using std::max; using std::cout; +using std::string; +using std::vector; using namespace dcp; struct SoundAssetWriter::ASDCPState @@ -53,12 +56,17 @@ struct SoundAssetWriter::ASDCPState ASDCP::PCM::AudioDescriptor desc; }; -SoundAssetWriter::SoundAssetWriter (SoundAsset* asset, boost::filesystem::path file) +SoundAssetWriter::SoundAssetWriter (SoundAsset* asset, boost::filesystem::path file, bool sync) : AssetWriter (asset, file) , _state (new SoundAssetWriter::ASDCPState) , _asset (asset) , _frame_buffer_offset (0) + , _sync (sync) + , _sync_packet (0) { + DCP_ASSERT (!_sync || _asset->channels() >= 14); + DCP_ASSERT (!_sync || _asset->standard() == SMPTE); + /* Derived from ASDCP::Wav::SimpleWaveHeader::FillADesc */ _state->desc.EditRate = ASDCP::Rational (_asset->edit_rate().numerator, _asset->edit_rate().denominator); _state->desc.AudioSamplingRate = ASDCP::Rational (_asset->sampling_rate(), 1); @@ -87,6 +95,10 @@ SoundAssetWriter::SoundAssetWriter (SoundAsset* asset, boost::filesystem::path f memset (_state->frame_buffer.Data(), 0, _state->frame_buffer.Capacity()); _asset->fill_writer_info (&_state->writer_info, _asset->id()); + + if (_sync) { + _fsk.set_data (create_sync_packets()); + } } void @@ -115,14 +127,19 @@ SoundAssetWriter::write (float const * const * data, int frames) /* Write one sample per channel */ for (int j = 0; j < ch; ++j) { - /* Convert sample to 24-bit int, clipping if necessary. */ - float x = data[j][i]; - if (x > clip) { - x = clip; - } else if (x < -clip) { - x = -clip; + int32_t s = 0; + if (j == 13 && _sync) { + s = _fsk.get(); + } else { + /* Convert sample to 24-bit int, clipping if necessary. */ + float x = data[j][i]; + if (x > clip) { + x = clip; + } else if (x < -clip) { + x = -clip; + } + s = x * (1 << 23); } - int32_t const s = x * (1 << 23); *out++ = (s & 0xff); *out++ = (s & 0xff00) >> 8; *out++ = (s & 0xff0000) >> 16; @@ -149,6 +166,11 @@ SoundAssetWriter::write_current_frame () } ++_frames_written; + + if (_sync) { + /* We need a new set of sync packets for this frame */ + _fsk.set_data (create_sync_packets()); + } } bool @@ -168,3 +190,87 @@ SoundAssetWriter::finalize () _asset->_intrinsic_duration = _frames_written; return AssetWriter::finalize (); } + + +/** Calculate and return the sync packets required for this edit unit (aka "frame") */ +vector<bool> +SoundAssetWriter::create_sync_packets () +{ + /* Parts of this code assumes 48kHz */ + DCP_ASSERT (_asset->sampling_rate() == 48000); + + /* Encoding of edit rate */ + int edit_rate_code = 0; + /* How many 0 bits are used to pad the end of the packet */ + int remaining_bits = 0; + /* How many packets in this edit unit (i.e. "frame") */ + int packets = 0; + Fraction const edit_rate = _asset->edit_rate (); + if (edit_rate == Fraction(24, 1)) { + edit_rate_code = 0; + remaining_bits = 25; + packets = 4; + } else if (edit_rate == Fraction(25, 1)) { + edit_rate_code = 1; + remaining_bits = 20; + packets = 4; + } else if (edit_rate == Fraction(30, 1)) { + edit_rate_code = 2; + remaining_bits = 0; + packets = 4; + } else if (edit_rate == Fraction(48, 1)) { + edit_rate_code = 3; + remaining_bits = 25; + packets = 2; + } else if (edit_rate == Fraction(50, 1)) { + edit_rate_code = 4; + remaining_bits = 20; + packets = 2; + } else if (edit_rate == Fraction(60, 1)) { + edit_rate_code = 5; + remaining_bits = 0; + packets = 2; + } else if (edit_rate == Fraction(96, 1)) { + edit_rate_code = 6; + remaining_bits = 25; + packets = 1; + } else if (edit_rate == Fraction(100, 1)) { + edit_rate_code = 7; + remaining_bits = 20; + packets = 1; + } else if (edit_rate == Fraction(120, 1)) { + edit_rate_code = 8; + remaining_bits = 0; + packets = 1; + } + + Bitstream bs; + + Kumu::UUID id; + DCP_ASSERT (id.DecodeHex(_asset->id().c_str())); + + for (int i = 0; i < packets; ++i) { + bs.write_from_byte (0x4d); + bs.write_from_byte (0x56); + bs.start_crc (0x1021); + bs.write_from_byte (edit_rate_code, 4); + bs.write_from_byte (0, 2); + bs.write_from_byte (_sync_packet, 2); + bs.write_from_byte (id.Value()[i * 4 + 0]); + bs.write_from_byte (id.Value()[i * 4 + 1]); + bs.write_from_byte (id.Value()[i * 4 + 2]); + bs.write_from_byte (id.Value()[i * 4 + 3]); + bs.write_from_word (_frames_written, 24); + bs.write_crc (); + bs.write_from_byte (0, 4); + bs.write_from_word (0, remaining_bits); + + ++_sync_packet; + if (_sync_packet == 4) { + _sync_packet = 0; + } + } + + return bs.get(); +} + |