Input/Output Modules

FFMedia

I/O: file(.*)/video, video/file(.*)

This is the main input/output module used in SAVE 1.3.x to decode video streams from FFmpeg compatible files as well as output video stream data to H.265 encoded MP4 files. H.265 is the default codec used by SAVE to encode output from */video modules and store it on disk, and it can be changed by using the -codec flag to use H.264, or the novel H.266. Additionally, the quality of the compression can be controlled with the -crf / -qp flag at the command line. For more information about this flag, see FFmpeg's documentation on it.

FLAC

I/O: file(.flac)/signal, signal/file(.flac)

This is an experimental input/output module provided by SAVE v1.3.x for added compression of PCM signals. Using this module requires an installation of Xiph.org's FLAC toolkit that is accessible from the user or system PATH. FLAC output files are encoded with moderate compression and are tagged with a sample rate equivalent to one-thousandth of the original output sample rate of the originating SAVE command-line. For example, if SAVE outputs a 13.5 MHz signal to FLAC, the output container will report a sample rate of 13.5 kHz. Due to this encoding quirk, SAVE ignores the sample rate of FLAC containers used as input and instead interprets the file using the sample rate specified with the -srin flag.

Volta

I/O: file(.volta)/signal, signal/file(.volta)

This is a supplemental input/output module provided by SAVE for transparency and future use-cases. In SAVE 1.3.x, the Volta I/O module allows for storing/retrieving emulated analog voltage signals as system-endian, 16-bit signed sample data files. .volta files do not contain any metadata or headers, and can be imported/exported from audio programs like Audacity as raw data to interoperate with SAVE. Note that this also means that .volta files don't "remember" their sample rate, so it must be recorded/specified elsewhere (for example, at the command-line with -srin and -srout flags). This input/output option is currently only useful in cases where the user wants to see an oscilloscope-like view of modulated CBVS signals generated by SAVE.