Orinj Audio formats

Orinj version 9.0.0

Wave files used in recording and playback

A wave file (file with extension ".wav") contains sampled sound data – many of the values of the signal taken at different points in time. See Wave file format for more detail.

In the multitrack session, Orinj uses:

• Microsoft PCM (uncompressed) wave files with compression code 1 (see Format chunk (of a Wave file)), in which data is stored with 8-bit unsigned integers, 16-bit signed integers, or 24-bit signed integers.
• Microsoft IEEE float wave files (wave files with compression code 3) and data stored in 32-bit floating point values.

Both file types contain uncompressed digital sampled audio data. In both file types, the values of the analog sound signal are taken (sampled) at uniform intervals and the amplitude of the signal at each interval is recorded with numbers that use the same representation. Both types are therefore PCM files per the definition of PCM on this site.

• The rate at which the signal is sampled (the number of times the signal is sampled per unit of time) is the sampling rate.
• The representation of the numbers used to record the value at each sample is the sampling resolution. Usually, the sampling resolution is determined by the number of bits in used in the computer representation of the recorded numbers (for example, "16-bit").

Sound quality and dynamic range (the range of values used to record the signal) improve as sampling rates and sampling resolutions increase, but this happens at the expense of speed and disk space.

When storing and processing sound data, Orinj supports various sampling rates (up to 99.2 kHz) and various sampling resolutions (8, 16, 24, and 32-bit). Orinj also supports these sampling rates and sampling resolutions when playing and recording sound data. However, Orinj may not be able to play and record these if they are not supported by the audio device (i.e., the computer soundcard).

Wave samples in the loop building view

The wave files used in the Orinj loop building view are PCM waves (compression code 1), recorded with 16-bit signed data at 44.1 KHz.

The wave samples included in Downloadable Sounds (DLS) files and the PCM data in SoundFont files in the loop building view can use any sampling rate and resolution permitted by the two corresponding formats.

Other wave files

Orinj can open wave files with other compression codes, such as AIF, AU, A-law, and U-law wave files. Orinj will convert these files to wave PCM files and will use these newly created wave PCM files instead. The original files will not be changed.

Wave files have been in use for a while and there are many extensions of the wave file formats. Wave formats usually differ in two main aspects: how and where audio data is stored and what other data is allowed in the file. It is always possible to stumble upon a wave file (or a wave file chunk) that will not be recognized by Orinj.

MIDI files

MIDI files (files with extension ".mid") contain notes, instruments, and controllers, but not sampled audio data. While the MIDI standard defines how notes, instruments, and controllers should be described in the file, it does not define how these will sound on different devices. This choice is left to the manufacturer of the device or to the underlying (usually sampled PCM) data used to play the note. This means that one and the same MIDI file may sound differently on different devices.

A MIDI file created with Orinj has the following default properties.

• The file uses time division specified in pulses per quarter and resolution of 80 ticks per beat.
• The initial tempo is 750000 microseconds per quarter note or 80 quarter notes per minute.
• The initial time signature is 4/4, with one beat equal to one quarter note and with 24 MIDI clocks per metronome click.
• The initial volume in each of the 16 MIDI channels is -8 dB. Both coarse and fine volume controllers are included (see MIDI controller message).
• The initial pan in each of the 16 MIDI channels is center. Both coarse and fine pan controllers are included.
• The MIDI file contains proprietary meta message specifying the SoundFont file to be used for playback.
• The MIDI file format is 0 (a single MIDI track; see Musical Instrument Digital Interface (MIDI)).
• The file contains a single MIDI track with a single message (end of track).

When the user adds a note to the MIDI file, Orinj:

• Adds coarse and fine bank select controllers and program change messages to the file if those do not already exist for the specific channel. These are added to the beginning of the file.
• Chooses a channel for the new note. The channel is either a channel that already uses the instrument that plays the note or one of the empty channels if there is no channel with this instrument yet.
• Adds note on and note off messages.

Thus, in Orinj, each MIDI channel contains the notes for only one instrument and hence contains only one bank and one program change.

All events are added to a single track but may be sent to any of the MIDI channels as needed. Orinj can use MIDI files that have more than one track if those tracks are designed to be played simultaneously (type 1).

Orinj interprets a MIDI bank value of 128 as a bank of percussion instruments per General MIDI convention. Other banks may also include percussion instruments, but Orinj may not recognize those banks as percussion banks. This will not change Orinj playback but may impact MIDI files when played on other devices.

Orinj does not add controllers or messages other than the ones listed above. Thus, Orinj does not support the full General MIDI standard (see General MIDI 1 and General MIDI 2). When working with a MIDI file created outside of Orinj, Orinj will not remove or change controllers and messages other than those listed above.

When playing MIDI files, Orinj does not send MIDI data to MIDI devices. Orinj uses Downloadable Sounds (DLS) or SoundFont (SF2) files to translate MIDI messages into sound data and plays that sound data. Orinj only uses the MIDI standard to save MIDI files and read MIDI files for the MIDI roll view or for the multitrack session.

MIDI files inserted in an Orinj recording session are always converted to wave files. A temporary wave file is created for each MIDI file. The original MIDI file is preserved and can be modified in the MIDI roll view. This conversion of MIDI files to Wave files requires a DLS or an SF2 file and allows two things.

• The Orinj effects, which are designed to process wave data, can be applied to MIDI data.
• MIDI files will sound the same on different devices if the same DLS or SF2 file is used.

DLS and SF2 files

Downloadable Sounds (DLS) files (with extension ".dls") and SoundFont (SF2) files (with extension ".sf2") are used by MIDI synthesizers. These files contain sampled audio data in multiple samples and directions for MIDI synthesizers that state which wave sample should be played when the synthesizer must play a specific note on a specific instrument and how this wave sample should be played.

DLS and SF2 files in Orinj are used in two places:

• In the MIDI roll view, to play MIDI files. Each MIDI file in Orinj is associated with a single DLS or SF2 file.
• In the multitrack session view, to convert MIDI files to wave files. A single DLS or SF2 file can be used. If the MIDI file was created in the Orinj MIDI roll view, then Orinj will use the DLS or SF2 file that was opened when the MIDI file was created. If the MIDI file was not created in Orinj, Orinj will ask which DLS or SF2 file to use to convert the MIDI file to a Wave file.

Other files

The Orinj session files and loop files are specific to Orinj and are not files with a common audio format.