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ISO to DSF Conversion Audio Files [Frequently Asked Question]

Audio Basis - educational articles

Read answers to frequently asked questions about 1-bit audio ISO (a.k.a. SACD ISO) to DSF conversion of audio files.

ISO to DSF Conversion - Frequently Asked Questions



How to improve SACD ISO to DSF conversion speed?

Read details here >



How to improve SACD ISO to DSF conversion speed?

When you convert SACD ISO to DSF you can get:

  • clicks;
  • long file name issue;
  • non-English symbols issue.

Last two matters is issues of extraction under Windows rather.
Though on MacOS file name is limited [1]. And too long track name can cause file creating error. Because file name may be assigned as track name.

Some kinds of clicks can be eliminated via processing in automatical mode during conversion or manually via DSD editing >

Read more about clicks below.


What issues can I stumbled when convert SACD ISO to DSF?

If conversion is provided without processing, sound quality is the same for any ISO to DSF converter software.
There may be difference in functional abilities.

When processing is applied, various converters can cause different noise / distortion levels into output stuff.

Also sigma delta modulators, that used as final stage of DSD processing, may have diverse overload tolerance.
The overload can cause break of the modulator stability. To return modulator back to normal operational mode, force reset is necessary.

Overload tolerance does not impact to audio quality. But it allow to increase confidence in correct conversion result with less scrupulous control of level.

Different processing implementations might have different distortion / noise level.

Read more infomation about DSD modulator and demodulator >



What is quality difference between converters?

DSF and DFF provide same audio quality. It is different DSD containers with almost the same file size.

DSF provide metadata support standard way.

DFF provide lossless DST compression.

Read more about DSD vs. DSF vs. DFF >



There is difference between target DSF and DFF?

There are many click reasons. There is no universal approach to fix all click reasons.

If ISO is correctly created, extracted, played back, there should not be clicks during file playback.

If click can't be fixed automated way, need analize file's spectrogram and oscillogram at the click location.

Most likely clicks are located in begin and end of album tracks.

As rule, clicks have level about -60 ... -70 dB.

Read more about ISO click issues and how to fix it >



What is ISO extraction click issue?

No. Sound quality depend on ISO to DSF converter software implementation and its mode.

When software extract SACD ISO in bit-perfect mode, sound quality is same for any software and operation system.

Of course, software should works without bugs and ISO file be valid.



There is sound quality difference, when software extract SACD ISO on Mac, Windows, Linux?

No. Sound quality defined by a ISO to DSF converter software.



Does computer hardware impact to sound quality of ISO to DSF converter?

Higher processing quality define sound quality. Higher processing quality demands more calculation resources.

Sometimes small improvement may require significantly longer processing time.

But processing can be optimized and consume lesser resources in certain implementation. So processing time is not primary criterion of quality.

Conversion quality is defined by noise / distortion level, generated by converter software.



Does longer conversion time guarantee higher quality?

SACD contains music in DSD audio format. DVD-audio contains PCM audio format.

Final listening quality defined by record/mixing/post-production quality and implementation of recording/mixing/playback equipment (including software).

Theoretically, DSD DAC may have easier implementation for same quality comparing PCM one.

Read more about DSD vs PCM >



What is better SACD or DVD-audio?

Yes. ISO contains digital audio data identical to the original optical disk.



Does ISO and original optical disk contains the same digital content?

ISO contains:

  • audio data (either stereo or multichannel or both);
  • metadata (album name, album year, performer, track names, and other).



What contains ISO?

Author don't know about ISO extractor implementations that unpack individual track.



Can I extract individual track from ISO?

Yes. This processing called as "downmix".

It is lossy processing.



Could multichannel track be converted to stereo one?

Yes. This processing called as "upmix".

It is lossy processing.



Could stereo track be converted to multichannel one?

No. Downmix to 2.0 have many implementations.



Downmixed 5.1 to stereo track is the same stereo tracks into ISO?

No. Upmix to multichannel track have many implementations.



Upmixed stereo to 5.1 track is the same multichannel tracks into SACD ISO?

DSD editing distortions is comparable with resampling's ones: noise/aliases and ringing.

Pro-audio resamplers provide noise/distortion level significantly below electical noise of DAC.

Ringing look so scary at test square signals. But real music signals is sloper than square. And author don't know about researches that tested ringing impact to music perception.



How destructive DSD editing?

Portable digital audio player (DAP) have free disk space limitation.

ISO can contains two versions of one album: stereo and multichannel. As rule, portable DAP is stereo device.

Therefore, disk space may be saved through loading of album's stereo version only to the DAP's hard disk drive.

Stereo version of the album in DSF can be obtained via:

  1. extraction stereo track from ISO;
  2. multichannel track downmixing (processing during audio conversion).

Case #1 is more preferable, theoretically. Because stereo mix is made by musical producer specially for 2.0 systems.

Case #2 may be recommended, when ISO contains multichannel tracks only.

Read more about downmixing 5.1 to 2.0 quality issues >




  1. About maximal file length on Mac OS
  2. Ripping SACD (link 1)
  3. SACD ripping (link 2)



Read articles about DSD format

Read the articles

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