File and Project Interchange : File Interchange - Formats
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Please keep this in mind when recording and/or exporting to any of these formats, the 2GB/4GB limit might in fact
be quite close, particularly when working with high sample rate multitrack files.
Pyramix's WAV/BWF Media handler now accommodates RIFF64 removing the 2/4GB limitation. It does this in the
following way: Up to 4GB Pyramix creates a regular (legacy) WAV/BWF, but when a recorded media exceeds 4GB,
for example during a recording/render or mixdown, Pyramix will automatically and transparently start creating a
RIFF64 instead of a regular WAV/BWF.
When performing file interchange please be aware that the destination workstation/software must be compatible
with RIFF64 WAV/BWF to be able to read RIFF64 WAV/BWF files.
Similarly, some "old" applications may only recognize WAV/BWF as proper files if their file size remains below the
2GB limit.
Hard Drive Limitations
A very similar 2GB/4GB* limit can also be encountered the hard way when attempting to write large files, even in
PMF format, onto storage units (hard drives, memory cards etc.) formatted using an old 32bit file system such as
FAT32 or HFS.
Yet another, higher, limitation also exists with IDE ATA/ATAPI drives. This will show up at around 137GB. This may
be caused by part of a system (drivers, controllers and/or old Windows version) only recognizing the 28bit
addressing of the original ATA specifications, and not the enhanced 48bits available on newer equipment. This is
usually solved by installing fresh and or updated BIOS/Drivers/OS.
*The official limit is 4GB, but serious trouble can start at around 2GB.
PMF
PMF or Pyramix Media File is Merging Technologies native format. It carries a number of advantages when com-
pared with others, especially where multi-channel recordings are concerned.
• PMF has a 64bit addressing structure, so there is no 2GB limit.
• PMF can contain comprehensive proprietary metadata
Note: Please see: Appendix IIX - Pyramix iXML Implementation on page 744 for further infor-
mation.
The advantages of using interleaved PMF for multi-channel files (One file per track not selected) are:
• Contiguous blocks on disk so, when reading the same block (same time position) for all the Tracks at once,
the disk head does not have to do long and time-consuming seeks.
• It is not necessary to read samples for all Tracks when only one Track is required for replay. E.g. when using
a guide mix to edit a multitrack recording.
• Simpler Media Management, one file instead of say, 48 for a 48 track recording.
• Waveforms are embedded in the file."
The only time to consider using a different file format is when material must be exported to an application that
does not support PMF.
WAV and BWF
Wave and Broadcast Wave (BWF) files are supported by Pyramix. In Pyramix WAV/BWF is now RIFF64 compatible,
so the 2/4 GB file size limitation no longer applies.
The disadvantage of using WAV and BWF for interleaved multi-track recordings is that the audio is interleaved
sample by sample for all channels, which may adversely impact the overall throughput of hard drives or any other
storage media, particularly when only a subset of all channels present in such a file is being used on subsequent
playback.
Example: if, in a given Pyramix project, only channels 1 and 2 out of a 48 track BWF file are being played, the hard
drive's head will still have to spend the time scanning the entire data corresponding to all 48 tracks to just retrieve
the useful samples corresponding to those two channels. Alternatively, PMF with its much larger channel inter-
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