True Gapless Conversion of Audio Files
audio file converter for music production and hi‑end audio

True Gapless Conversion of Audio Files


For audio conversion of some album kinds (operas, symphonies, live concerts, musicals, shows, etc.) need to provide seamless (gapless) transients between neighbor converted tracks.

True Gapless Conversion (TGC) - seamless album conversion - allow avoiding artifacts at borders of neighbor converted tracks.


General description

What is True Gapless Conversion

There are albums like operas, live concerts, etc., where no pauses between neighbor tracks. Also, non-zero levels at track borders of the albums may be there.

Some ISO (1-bit audio) has a level bias (DC-bias, direct current bias) throughout a full album: at beginning and end of tracks DC-bias (non-zero level) is present. It can be heard as a click.

Level bias (DC-bias) thru full album

ISO DC bias (1-bit HD audio)

In conversion may be applied audio processing:

  1. Resampling (sample rate altering)
  2. Altering 1-bit audio stuff (DSF, DFF, ISO).

In conversion without the processing, there are no artifacts at output-track borders.

But, if each album track (file) is processed separately, non-zero level at input-file border generates artifact at output-file border. Because the processing is re-initialized for each track.

For seamless audio processing of the album, all its audio files may be processed as a continuous audio stream without re-initializing of processing for each track (file).

Audiophile Inventory's trueG seamless conversion algorithm allows seamlessly process neighbor tracks of album.

True gapless mode switched in AuI ConverteR's main window > Parameters tab (upper left):

turn ON (checked state) / OFF (unchecked state).

Management of True Gapless Conversion mode

True gapless conversion management

Here merged converted neighbor album tracks are shown

True gapless conversion spectrum


If True Gapless Conversion is turned OFF, we see noise splash on border of merged resampled converted tracks. The splash at spectrum shows short level increasing, which is absent in source files.

The noise splash is an additional ringing artifact rising due to a rather significant non-zero level at beginning or end of file. It happens when resampling filter gets sharp level transient.

If True Gapless Conversion is turned ON, we see seamless transient between resampled converted tracks. Like input source files.

In this case, resampling filter gets a continuous input stream and have no additional ringing at the output.

AuI ConverteR 48x44 provides True Gapless Conversion for the following conditions:

  1. All input (source) tracks (files) must have the same sample rate and bit depth.
  2. Input tracks must be sorted in album order.



  1. True gapless mode can't use multi-CPU capability. Because files (album tracks) should be processed sequentially. To convert the next audio file, converter state at end of the previous track is needed.
  2. Audio player (software or hardware), that playback processed files, should support gapless (seamless, without re-initialization on each file) playback. All files should be played back as a continuous stream.


What AuI ConverteR's editions support the True Gapless Conversion

AuI ConverteR FREE allows testing True Gapless Conversion with 2-second silence at the middle of converted files, including ISO 1-bit-audio files.

True Gapless Conversion is supported in:



You can either buy unlimited-time license and pay for major updates (... 10.x > 11.x > 12.x > ... versions).

Full functionality

[FOR CONFIGURABLE Modula-R edition]
"True Gapless Mode (add-on)" module (requires "Base (core)" module)
for DSD file processing, additional modules are also needed

[WINDOWS]         [     MAC      ]



Read about sound quality

  1. How to Improve Sound Quality >
  2. What is optimization audio for DAC >



Read also

How Convert ISO to DSF, WAV, etc. without Clicks (Mac OS X and Windows) >

November 19, 2021 updated | since February 18, 2015

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