The predecessor to this package (ProTrackR) was entirely programmed in R. Although technically possible, it was challenging and slow with recursive algorithms. The new version is a complete overhaul in C/C++, based on Olav Sørensen’s ProTracker clone. With it, came some design changes which are worth mentioning here.
The table below summarises the differences between ProTrackR2 and its predecessor.
| Feature | ProTrackR | ProTrackR2 |
|---|---|---|
| Effect commands | Limited set implemented | All PT2.3d effects implemented |
| Infrastructure | R script | Compiled C/C++ |
| File readers | Optimized for format preservation | Optimized for PT2.3d compatibility |
| Audio output | tuneR S4 Wave class | audio S3 audioSample class |
| OpenMPT test cases | Passes 6 out of 12 selected tests | Not tested yet |
ProTracker uses specific codes to apply certain effects or position
jumps. ProTrackR implements only a subset of these effects,
whereas ProTrackR2 has implemented all ProTracker
compatible effects.
The predecessor only partly implemented arpeggio and setting finetune. It did not implement glissando, sample filtering (E8) and loop reversal (EF). All these effects are implemented in the current package.
For a full overview of effect commands see
vignette("effect_commands").
By switching to C and C++ compiled code,
the new package gained a significant performance boost (see benchmark results). Where the in the predecessor
the module was represented by a vector of raw data, an
externalptr to a C struct is used in the
current package. This required a slightly different approach to handle
these objects. In order to avoid confusion about the syntax, it was
completely redesigned in the successor.
A benchmark test where the same module (the one provided with this
package) is rendered with both ProTrackR and
ProTrackR2. The settings for both tests were similar and
performed on the same system and repeated 10 times. On average
ProTrackR2 renders 8.8 times faster than
ProTrackR.
While reading ProTracker modules, the predecessor preserved the data in the file. It only modified / fixed data when requested by the user. The current package will always sanitise data while reading it, making it compatible with ProTracker 2.3d. The current reader is also a bit more flexible and allows to read more exotic formats. It even allows you to read files compressed with PowerPacker.
If you want even more flexibility, check out the openmpt package. It uses libopenmpt to read and play modules. This library has a more extensive set of supported file formats. The downside is that it does not allow you to modify or save modules.
The predecessor used tuneR objects to
store rendered audio. In the current package we use audio objects. This
switch was made as the S3 class objects from ‘audio’ are
easier to handle than the stricter and formal S4 class
objects from ‘tuneR’. If you wish to use the advanced features from the
‘tuneR’ package, this is still possible as both formats can be converted
relatively easy.
## Load demo module
mod <- pt2_read_mod(pt2_demo())
## render 'audioSample' object
mod_audio <- pt2_render(mod)
## Convert from 'audio::audioSample' to 'tuneR::Wave' object:
if (requireNamespace("tuneR")) {
mod_tuneR <-
tuneR::Wave(
left = as.integer(2^15*unclass(mod_audio[1,])),
right = as.integer(2^15*unclass(mod_audio[2,])),
samp.rate = attributes(mod_audio)$rate,
bit = attributes(mod_audio)$bits
)
}