PM123 improvements

This is a development branch of the PM123 sources. The new features will most likely be part of PM123 1.40. Some components may be used with older PM123 versions too.

The PM123 components on this page may not be stable. If you are looking for stable versions go to ftp://ftp.ptv.ru/pub/glass/pm123/ or http://pm123.ptv.ru/ respectively.

However, if you want to contribute to the further development, detailed bug reports would be appreciated.

Task list

PM123 core engine

Task list (plug-ins)

PM123 version 1.41-alpha

Develpoment of this release is in progress. The main goals are performance improvements and stabalization. The latter requires a major change in the core engine because the newly introduced engine of PM123 1.40 had some serious draw-backs.

PM123 version 1.40-alpha4

Download

1.40 alpha4 Binary
1.40 alpha4 Binary (logging support)
1.40 alpha4 Source

Note that the 'logging' build is slower, but it provides support for detailed error tracking and bug reports. Furthermore the logging can cause drop outs in the audio at heavy system load because of the reduced priority of the logging output during DART events.

Installation

Unzip the binary zip file to a new folder. You may use configuration files from older PM123 releases. Most of your settings will survive. But do not copy an PM123.INI file from PM123 1.32 to another folder. There are restrictions when using older plug-ins.

Bug reports

If you encounter problems with this release you may send a bug report to the contact address below. A bug report should contain

• a short description of the problem,
• the release and the time stamp of PM123.exe and
• an exact description how to reproduce the problem with a newly started PM123.

If it is not straight forward to reproduce the problem please try enabling the logging to capture useful information. You get the log file by starting PM123 (binary with logging support only!) from the command line with:

 C:\app\pm123>pm123 2>log.txt

Please keep the playing time as short as possible, when creating a log for a bug report, because the log file grows rapidly. If you manage to reproduce the problem with a hopefully small log please compress it and attach it to the bug report. Mails with some megs of attachments may not reach their target.

Information

Playlists may now be nested - even recursive. More the one playlist window can be open at the same time. Now Playlist Manager, playlists and bookmarks are basically the same.

The playback controller now prefetches songs of playlists and keeps the output device open. This avoids gaps between items in playlists.
Furthermore you can navigate within the playlist with the slider using the Alt key.

The plug-in interface has been significantly improved. This interface allows more flexibility to buffer handling and filter plug-ins. This is required for future plug-ins like digital room correction. The new plug-in manager checks whether the PM123/plug-in pair is likely to work. It can load all old plug-ins except for visual plug-ins through a virtualization layer. The visual plug-in compatibility is broken since PM123 1.32 anyway.

Documentation

Online help
Plug-in development kit documentation

Previous versions

1.40 alpha3 Binary
1.40 alpha3 Binary (logging support)
1.40 alpha3 Source

1.40 alpha2 Binary
1.40 alpha2 Source

1.40 alpha1 Binary
1.40 alpha1 Source

RealEQ Version 1.22 beta

Download

Binary (REALEQ.DLL, requires PM123 version 1.40a2 or higher)
Source (requires PM123 1.40 source tree to build)

Download the PM123 1.40 files to get the plug-in. RealEQ 1.22 is included.

Installation

Copy the DLL to your PM123 folder and add the plug-in using the properties dialog.
This file is included in PM123 version 1.40 and should already be in-place.

Information

• RealEQ does no longer delay the playback and cut the last samples. It operates now as zero-phase filter using read-ahead. This gives a very fast response to user actions like seek.
• Enabling/disabling the EQ does no longer cause the playback to jump.
• Changing the FIR order does no longer cause large glitches. (Small glitches remain since you effectively changed the transform function.)
• The maximum FIR order is now 16384, giving very accurate results.
• The maximum FFT size is now 32768. This causes reasonable low CPU usage even with large FIR orders.
• The MMX and FFT convolution is finally removed. Both are outperformed by the new FFT convolution.
• The output of the equalizer is now stereo even if the input is mono. This is because the filtering in general gives different results for the two channels.
• The equalizer can equalize the group delay. This is a very powerful feature if you know how to use it. It can compensate for group delays of crossovers, vented enclosures or room resonances.

Internals

Comparison of the different RealEQ versions.
Frequency response of the equalizer at 44,1kHz sampling rate when all sliders are set alternating to +12dB and -12dB and the FIR order is at the maximum for the particular version.

X-axis: frequency [Hz]
Y-axis: amplitude [dB]

Black line: RealEQ version 1.20, FIR order 4096
Green line: RealEQ version 1.21, FIR order 12288
Red line: RealEQ version 1.22, FIR order 16384
Blue line: RealEQ version 1.22, FIR order 4096

Even at the same filter order of 4096 the new equalizer performs better by nearly a factor of two.

LogVolum Version 1.0

Download

Binary (LOGVOLUM.DLL, requires PM123 version 1.40 or later)
Source (requires PM123 1.40 source tree to build)

Download the PM123 1.40 files to get the plug-in. LogVolum is included.

Installation

Copy the DLL to your PM123 folder and add the plug-in using the properties dialog.
This file is included in PM123 version 1.40 and should already be in-place.

Information

This small plug-in turns the characteristic of the volume control in PM123 from linear to logarithmic.

You may use this plug-in to compensate for the linear characteristic of the volume controls of the many common sound devices.
Do not use this plug-in if your sound card already has a mixer with a logarithmic characteristic.

Internals

Response of the PM123 volume control.

X-axis: relative position of the volume slider [%]
Y-axis: gain [dB]

The red line is the response function with the correction.
The green line is the response function of usual sound devices without this plug-in.

Instead of an exponential function the plug-in uses the polynomial:

	y =	x
		1 + sqrt(10) · (1 - x)

with x and y in the range [0,1] for the transformation. This gives an approximately exponential function with a usable dynamic range of almost 30dB while keeping the zero point at -∞dB.

OS2rec Version 1.0 beta

Recording plug-in for PM123.

Download

Binary (OS2REC.DLL)
Source (requires PM123 1.40 source tree to build)

Download the PM123 1.40 files to get the plug-in. OS2rec is included.

Installation

Copy the DLL to your PM123 folder and add the plug-in using the properties dialog.
This file is included in PM123 version 1.40 and should already be there.

Note: Although OS2rec does not strictly depend on a recent PM123 version bugs in older PM123 builds makes it nearly impossible to use the plug-in. PM123 before 1.32 simply does not accept URL inputs which do not start with http://. The only way to get it working is to edit a playlist file and insert an URL with record:///...

Usage

To start the recording right click PM123, choose Load..., Record... and follow the dialog. Alternatively choose Load..., URL... and enter an URL of the following style:

record:///[sounddevice][?param1=value1[&param2=value2[&...]]]

sounddevice is either a device ID (integer number) or a name of a mixer device usually AMPMIXxx. The Device ID 0 is the default MMOS2 sound device.
The parameters below may be used to control the recording parameters.

Parameter	Value	Default	Remarks
samp[lerate]	Sampling rate in kHz	44100
ch[annels]	Number of channels (usually 1 or 2)	2
mono	- none -		Alias for channels=1
stereo	- none -		Alias for channels=2
bit[s]	Number of bits per sample and channel	16
share[d]	y[es]|n[o], default: yes	yes	Using the non-shared mode will also block other mixers from working.
in[put]	l[ine]|m[ic]|d[igital]	line

Examples:

record:///	Start recording from the default sound device with default parameters: 44,1kHz, stereo, use line in
record:///ampmix01	Start recording from the specified sound device
record:///0?samplerate=48000&mono	Start recording from the default sound device with 48kHz sample rate and only 1 channel
record:///0?input=mic	Start recording from the default microphone input.

Known issues

• The plug-in should introduce a defined latency before passing the buffers to the output.
  Since the playback is normally absolutely synchronous you may never get the buffers filled. So drops in the sound are very likely to happen.
• When the recording and the playback is not done on same physical sound device it may get out of sync with time because the two sound devices do not use exactly the same sampling rate. This will cause dropouts or jumps whichever is the faster device. Most likely this will never get fixed.

RealEQ Version 1.21

Download

Binary (REALEQ.DLL, should work with all versions of PM123)
Source (requires PM123 1.32 source tree to be build, see http://pm123.ptv.ru/)

Installation

Replace REALEQ.DLL in your PM123 directory by the one above. PM123 must not run meanwhile.

Information

The new plug-in give you an additional choice how to do the convolution: FFT convolution. I strongly recommend to use the new FFT convolution, since it is far superior. Furthermore it does not depend on CPU features like MMX. It scales with O(log n) with the FIR kernel length whereas the other methods scale O(n).

Now the maximum FIR kernel length is 12288. I recommend to use this maximum together with the maximum FFT plan size of 16384 unless your CPU sets you a more restrictive limit. Otherwise the first three sliders at 16, 20 and 25Hz will not perform very well. But do not try to use these values without FFT convolution.
You may reduce the FIR kernel length if (and only if) the low frequency sliders are set to the same value or at least very close together. For each consecutive slider which has the same value than the 16Hz one you may shorten the FIR kernel length by about 26%.

The FFT plan size in the settings dialog has now no more meaning unless you choose FFT convolution. The plan size for the FIR kernel design is now chosen automatically.

Internals

The new FIR kernel design derivate in three main aspects from the old one:

• The desired frequency response function is now interpolated between the supporting points with a sine² function. This avoids unreasonable sharp jumps in the frequency response and makes the filter kernel shorter.
• The filter designer does no longer create 32 base functions in the time domain which are mixed when an equalizer slider changes. Instead, the FIR kernel is always created from scratch. This reduces the memory footprint by 1,6MB. Instead of that a DCT transformation is required now on each parameter change. However, this is required anyway to support the FFT convolution.
• The windowing function is much more aggressive now. The results in a worse stop band attenuation. However, since the equalizer does not provide more than 24dB dynamics anyway this is reasonable. Additionally the sine² interpolation above acts like a window function too.

Frequency response of the equalizer with an FIR length of 12288 at 44,1kHz sampling rate when all sliders are set alternating to +12dB and -12dB.

X-axis: frequency [Hz]
Y-axis: amplitude [dB]

The black line is the intended frequency response.
The red line is the achieved frequency response.
The green dots are the (first) supporting points used for the filter design.

Comparison of the new implementation.
Frequency response of the equalizer at 44,1kHz sampling rate when all sliders are set alternating to +12dB and -12dB.

X-axis: frequency [Hz]
Y-axis: amplitude [dB]

Black line: real frequency response of the old implementation with the maximum FIR order of 4096. Nothing reasonable happens below 100Hz!
Red line: real frequency response of the new implementation with the maximum FIR order of 12288.
Green line: extrapolated frequency response of the old implementation with an FIR order of 12288. This is only to compare the filter design, since the old convolution core was too slow for this filter order.

Spectrum Analyzer

Discontinued. Newer version included in PM123 1.40.

Download

Binary (ANALYZER.DLL, requires PM123 1.32beta or above, ftp://ftp.ptv.ru/pub/glass/pm123/)
Source (requires PM123 1.40 source tree to build. PM123 1.32 or above works with minor source changes, see http://pm123.ptv.ru/)

Installation

Replace ANALYZER.DLL in the sub folder visplug of your PM123 directory by the one above. PM123 must not run meanwhile.

Information

The new plug-in version adds two more visualization types:

• a linear spectroscope, scrolling from bottom up and
• a logarithmic spectroscope, scrolling right to left.

The spectroscope shows the amplitude as the color, the frequency as screen location and the time as screen location in the other direction. The dynamic range of the spectroscope is 40dB. Due to the usual nature of the frequency distribution in common music an additional weight function which scales with the square root of the frequency is multiplied to the amplitude before visualization.

This version of the analyzer also offers a new option called "high precision mode". This will take twice as much samples for analysis. Of course, the CPU load will increase. However, I recommend this at least for the logarithmic spectroscope to get more reasonable results.

Compatibility of PM123 1.40 with other, older plug-ins.

Note: When loading older decoder plug-ins you might want to add some extended attributes file types to the plug-in in the properties dialog. This enables you to play files without the standard extensions.

Contact

Suggestions, help, complaints (but not too much:-):

Original homepage: http://www.maazl.de/project/pm123/index.html