FLAC Lavf / Lib Encoding on server

[kenval]

Having had problems replaying 2 196/24 bit FLAC files on my Innuos ZEN+ ( VortexBox) downloaded from HD Tracks ( UK & USA ) I referred this to Innuos for resolution and they have advised the issue is with the encoding ( see attached). Apparantly the HD tracks encoding of Lavf has a issue with the server as opposed to the reference Lib format which does not. Innuos suggest conversion of the file to WAV and then back to FLAC to resolve, which works but i clearly hear a compression in the sound quality especially with cymbals ( less decay) and loss of ambience in voices.

No idea what these conversions are doing to the bit depth or compression and wonder if anyone has more specialist knowledge on this issue of file conversion and impact of audio quality etc??

Thanks in advance. 

[mansr]

2 hours ago, kenval said:

Having had problems replaying 2 196/24 bit FLAC files on my Innuos ZEN+ ( VortexBox) downloaded from HD Tracks ( UK & USA ) I referred this to Innuos for resolution and they have advised the issue is with the encoding ( see attached). Apparantly the HD tracks encoding of Lavf has a issue with the server as opposed to the reference Lib format which does not. Innuos suggest conversion of the file to WAV and then back to FLAC to resolve, which works but i clearly hear a compression in the sound quality especially with cymbals ( less decay) and loss of ambience in voices.

No idea what these conversions are doing to the bit depth or compression and wonder if anyone has more specialist knowledge on this issue of file conversion and impact of audio quality etc??

Thanks in advance. 

First let's be clear that the issue here is with the Innuos software, not the files. If other programs decode the files correctly, it means they are fine. They really ought to fix this even if a workaround is exists.

 

As for sound quality, there should be no change unless you made a mistake when re-encoding the files. I have worked with both code bases (lavf and libflac), and I can assure you that the processing is perfectly lossless. You can easily verify that the files contain identical audio data by converting both to WAV and comparing those files. The "compression" figure in your screenshot refers to the size reduction, not any change in actual audio content.

 

What software did you use for the conversion? I'd suggest you double-check the settings to make sure you didn't accidentally enable some processing or other. Also make sure the intermediate WAV file has 24-bit (or 32-bit) integer format and not 16-bit or floating-point.