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roskilde96
06-12-2007, 04:07 AM
Hi

I've converted some Flac files to EBU Wav files, using 48 KHz, 256 bits stereo and adding two DSP effects: trim silence at beginning and ending and add Replay Gain (using Normalizing). I've also ripped some music directly from CD to the same EBU format with the same DSP settings.

What I've noticed is that most of the converted files sound as if they are 8 bit or so, because in quieter parts they sound "distorted".

What could cause this problem?

Thanks ...

Spoon
06-12-2007, 06:57 AM
It is a known issue with R12.1, see the 2nd to last message:

http://forum.dbpoweramp.com/showthread.php?t=12018

roskilde96
06-12-2007, 07:28 AM
Thanks!
I'll wait for the new release to reconvert the files.
Do you have any idea if that release is for the next days or will it take a longer time?

Kind regards!

Spoon
06-12-2007, 08:33 AM
About 2 weeks.

roskilde96
06-13-2007, 07:39 AM
Can I "bypass" this problem by first encoding to standard wav files, using the DSP settings "trim silence" and "replay gain" and when that's done, convert these wav files to BWF EBU files?

Thanks!

Spoon
06-13-2007, 08:34 AM
No the problem exists doing the actual dsp effects. I think if you do one effect at once then you would not have the problem (each time converting to wave).

roskilde96
06-13-2007, 09:13 AM
Well, I did some more tests ... The problem seems to be in the BWF file format.
When I take the original file (FLAC) and I convert to BWF (without DSP effects) or I take a normal wav file and I convert to BWF, the result sound distorted. I use 48 KHz, 256 kbps stereo for the BWF file output.
It sounds a bit like a bad reception of a radio channel ...

Spoon
06-13-2007, 09:33 AM
What is the settings of the flac file? bit depth, sample rate, channels?

roskilde96
06-13-2007, 10:24 AM
The Flac is 44,1 KHz, 16 bit, 2 channels (stereo) 1,411 kbps.

But even when I rip directly from an audio cd to BWF, 48 KHz, 256 kbps, stereo, I get the same distorted result.

Using a headphone, I can hear the difference in audio quality even better than through my desktop speakers.

Regards!

roskilde96
06-13-2007, 11:28 AM
In addition to my previous message, I get the same distorted sound when converting to the Dalet format (48 KHz, 256 kbps, stereo).

Maybe a problem with the conversion from 44,1 to 48 KHz?

LtData
06-13-2007, 02:44 PM
If you convert to a 44.1KHz Dalet or BWF file, do they sound correct?

Spoon
06-13-2007, 04:44 PM
Try a DSP effect Resample, and set to 48 KHz

Spoon
06-13-2007, 04:52 PM
Both BWF and Dalet codecs were updated a week or so ago (different from the beta versions), are you sure you are on the latest versions?

BWF is now R5 and Dalet is R3

I have tried a 44khz file 16 bit 2 chan to bwf 48Khz 256khz and stereo and it sounds perfect.

roskilde96
06-14-2007, 03:34 AM
Hi Spoon

I'm using BWF R5 and Dalet R3.
I've zipped some audio samples audio.zip (http://www.box.net/shared/qfbyv82j2n) to let you hear what I mean.
There are 3 folders containg files, one with the original wav files 16 bit 44,1 KHz stereo. One with an MP3 example converted with Lame CBR 256 kbps and then a folder containg the BWF files. One of the audio samples is a 1KHz tone.

Maybe you could try to use my original 1KHz wav file and convert it to the BWF file format. (BWF 48 KHz, 256 kbps, stereo).
Could you please let me know if your converted file sound different then mine?

Thanks in advance!

Spoon
06-14-2007, 06:44 AM
The files seem to have no distortion to us, and played ok on our BWF checking programs.

Try this:

Convert the BWF r5 1KHz file to flac (important it is flac as it will not preserve the bwf chunk), then convert to a Wave (pcm uncompressed, everything as source). Play the wave file (say in media player) and see if it is distorted to you. If not then we have to find why your device / program is not liking the file.

roskilde96
06-14-2007, 07:49 AM
I've encoded the "distorted" BWF file to Flac and then to an uncompressed wav, both as wav 48 KHz and wav 44,1 KHz, but the distortion is still there.

Especially using the 1 KHz tone, I hear the difference in quakity (Listening with a Beyerdynamic DT 770 Pro headphone).

I'm gonna try a clean windows install (won't take long, I have a system image file). I'll let you know if that helps...

roskilde96
06-14-2007, 08:38 AM
I'm back ;-) Just did a clean OS install (ghost image) and reinstalled dBpoweramp. Unfortunately with the same results ... After conversion to BWF (R5) the 1 KHz tone sounds different (distorted).

Could this be a system issue? My sound card is able to handle upto 96 KHz and 24 bit audio ... So, it should be able to handle 48 KHz and 16 bit.

As an example, I've recorded the mix of my sound card and played back the 1 KHz tone as plain wav file first and then the BWF version. Here (http://www.box.net/shared/tbkach2j2v) you can download the recording, it's a normal wav file at 48 KHz and 16 bit stereo, containing the recorded playback of both tones.

Could you tell me if you hear the difference between those two recordings?

I'm really sorry for all this, but I need to find out what causes this problem before converting my entire music collection ...

Best regards and many thanks!

roskilde96
06-14-2007, 12:18 PM
Me again ;-)

I get better results when enabling "professional frequency conversion" (didn't know of this feature) especially with the 1 KHz tone, but still there's a difference in quality ... The quiet parts of songs seem to have a sort of digital noise. It's worse without the professional frequency conversion but with it, it's still there. I tried a lot of file converting combinations. Flac - WAV - BWF, rip from CD to BWF, all with the same result.

Loud parts sound OK because then the noise is not really hearable.

I can't imagine this is typical for the BWF file format, it's a pro (EBU) format.

Regards!

Spoon
06-14-2007, 12:40 PM
It is a fundamental when converting between frequencies. Using the pro-frequency conversion will give much better results, but when looking at the 1 Khz sine wave, you will see slight distortions of the wave.

Try this, convert your 1KHz wave (original) straight to linear PCM wave, 44Khz >> 48 Khz, with the pro frequency conversion on. Can you hear the distortions?

roskilde96
06-14-2007, 02:02 PM
No, it doesn't sound distorted when converting the wav file to 48 KHz.
Maybe something with the BWF compression ...

Spoon
06-15-2007, 05:05 AM
BWF is mp2, more to try:

convert your 48khz wave file to bwfmp2 256kbps, 48 khz - is distortion there?
convert the 44Khz original wave file to bwf 256kbps 44khz - is distortion there?

mange
06-15-2007, 09:42 PM
BWF is mp2

My harddisk recorder writes Broadcast wave files wich are .wav files with some more tags in them. Timecode and such.

Spoon
06-16-2007, 05:23 AM
You will be able to use R12.2 to write BWF linear wave files.