Spectral Band Replication Filter in Adobe Audition, Audacity or other

[fbreve]

I have a VHS capture and I'm now trying to restore the audio.

Using Adobe Audition, I used the equalizer to cut anything below 40Hz and above 8KHz, since apparently there is only noise in these frequencies (source is non Hi-Fi EP recording).

Then I used the automatic clicker remover.

I may or may not use noise reduction. I’m not getting alien artifacts, but I can see by hearing just the noise that I’m losing information, so maybe I’ll avoid it.

But in the end, I’d like to enhance the audio so it’s more bright. Just increasing higher frequencies will only bring back the noise. Reading old threads here I found pandy suggestion to use a "spectral band replication filter" as "crystality" or "crystalizer". My question is: is there such a plugin for Adobe Audition, Audacity or any other free software?

[redwudz]

Some listing of filters available for Audacity: http://manual.audacityteam.org/man/index_of_effects_generators_and_analyzers.html
There is also a: http://manual.audacityteam.org/man/spectral_edit_multi_tool.html
And some info about other plug-ins: http://www.audacityteam.org/download/plug-ins/

[fbreve]

Thank you. But I didn't find anything related to spectral band replicator on these filters.

I found the Mastering effect in Adobe Audition, though. I'm still messing with its settings, but apparently the "Subtle Clarity" preset does increase the brightness without adding too many noise. I even increased the "exciter" slider a little and it sounds much better than the dull sound I had after eq filters and denoising.

[pippas]

Take a look at the 'Multi band compressor' VST plug in in Audition. There are a number of presets you can try - or you can of course create your own - and you can adjust each band as you preview the audio,if you wish.
Splitting the spectrum into 4 bands makes for a much more versatile compressor than the normal single band versions. You should be able to increase the brightness - of the mid range especially - without introducing too many nasty artifacts...

[fbreve]

Thanks. I'm trying Multi Band Compressor with Enchance Highs preset. The difference is small, but then it should require less agressive 'exciter' on the next step.

[fbreve]

Here is a sample of the original audio and the restored version. I don't have experience on this, so I don't know how I can improve it. Maybe I applied too much noise reduction.

[pippas]

I'm not sure I would bother with noise reduction on track like this?.. There is a lot of background noise from the cars anyway, and introducing noise reduction will probably give some odd artifacts .
Just applying some mid range boost and compression should help to extract a bit more 'presence' from what is - as you say - a pretty muffled source.
The attached sample has no noise reduction (obviously!) and just applies some mid range boost and compression from the Audition Multi-compressor. Try the 'raise vocals' preset as a starting point....

[pandy]

I know only one filter that work like SBR - crystality - part of the ffdshow - it works only in 44.1kHz correctly and sometimes can be unstable - this is DirectX filter - should be accessible from Avisynth (due direct ffdshow plugin) or any software where DirectX audio filters can be used, this is sad that this is only filter to perform SBR.

[fbreve]

I'm not sure I would bother with noise reduction on track like this?.. There is a lot of background noise from the cars anyway, and introducing noise reduction will probably give some odd artifacts .

This is just the first of more than a dozen tapes. What I learn from this one I may apply on the others. This is the only car race, the noise may be much more noticeable on the other tapes.

But regarding this one. Engine sounds are desirable, tape hiss and clicks are not.

Just applying some mid range boost and compression should help to extract a bit more 'presence' from what is - as you say - a pretty muffled source.
The attached sample has no noise reduction (obviously!) and just applies some mid range boost and compression from the Audition Multi-compressor. Try the 'raise vocals' preset as a starting point....

I'm giving up on Noise reduction. It doesn't worth due to the artifacts and losts. I'll keep the automatic click remover and the low pass and high pass filters, though. Clicks are annoying and there is only noise above ~8 KHz.

I tried multi-compressor, but either I can't find the right setup or it's not really what I was looking for. I'm trying to rebuild high frequencies which were lost as the are out of the tape response. Equalizers and compressors will raise something that is not there, they are basically only bringing back the noise that the high pass filter faded.

The Exciter effect, on the other hand, seems to try to reconstruct high frequencies from the low frequencies. The result is a lot brighter than anything that could be stored on tapes without HiFi. Unfortunatelly, the hiss is also enhanced.

Attached are two other samples.

The first one is exciter on 80%, reverb 10%, loudness maximizer 20%.
The second is just the Bright Hype preset. This is pretty much what I am looking for, except for the noise.

[fbreve]

I know only one filter that work like SBR - crystality - part of the ffdshow - it works only in 44.1kHz correctly and sometimes can be unstable - this is DirectX filter - should be accessible from Avisynth (due direct ffdshow plugin) or any software where DirectX audio filters can be used, this is sad that this is only filter to perform SBR.

Thank you. Indeed, it's sad.

[pandy]

I know only one filter that work like SBR - crystality - part of the ffdshow - it works only in 44.1kHz correctly and sometimes can be unstable - this is DirectX filter - should be accessible from Avisynth (due direct ffdshow plugin) or any software where DirectX audio filters can be used, this is sad that this is only filter to perform SBR.

Thank you. Indeed, it's sad.

You may give a chance to Graphstudio to create such data flow wav->crystality->wav - and yes it is strange that crystality is the only known open source SBR implementation as it looks like very best candidate to deal with Cinavia protection (lowpass 7.5kHz and rebuild missing spectrum with SBR ).

[pippas]

The 'Mp3pro' options in Audition employ SBR of course, but I'm not sure that has any application here?....

[fbreve]

I know only one filter that work like SBR - crystality - part of the ffdshow - it works only in 44.1kHz correctly and sometimes can be unstable - this is DirectX filter - should be accessible from Avisynth (due direct ffdshow plugin) or any software where DirectX audio filters can be used, this is sad that this is only filter to perform SBR.

Thank you. Indeed, it's sad.

You may give a chance to Graphstudio to create such data flow wav->crystality->wav - and yes it is strange that crystality is the only known open source SBR implementation as it looks like very best candidate to deal with Cinavia protection (lowpass 7.5kHz and rebuild missing spectrum with SBR ).

Thanks. I tried that. Indeed, it works. I didn't figure out how to save the results, I only heard them. The effect is similar to Audition exciter, but much milder, even when Crystality settings are at the maximum.

[fbreve]

The 'Mp3pro' options in Audition employ SBR of course, but I'm not sure that has any application here?....

Maybe saving as MP3pro and loading back could trigger the effect, but that would lead to another bunch of problems due to the compression artifacts that might be inserted.

[pandy]

Thanks. I tried that. Indeed, it works. I didn't figure out how to save the results, I only heard them. The effect is similar to Audition exciter, but much milder, even when Crystality settings are at the maximum.

I've tried with f1 example - first it ends with 4kHz, i stacked in graphstudio 3 times crystality filter, at the end of graph i use AVI muxer filter then write file filter - i see useable bandwidth extended to 7kHz. It is better to normalize level in a range -20 ... -16dBFS to avoid distortions. Perhaps you need to repeat such operation multiple times but i believe there is no sense to push this so much...

Maybe saving as MP3pro and loading back could trigger the effect, but that would lead to another bunch of problems due to the compression artifacts that might be inserted.

It will not work, you need something called blind bandwidth extension - it use similar principle as spectral band replication - difference is that codec know all information and loose some of those information but store data how to recover its imitation - blind bandwidth extension have no information about lost information and it extrapolate spectrum from envelope of the existing data.
https://en.wikipedia.org/wiki/Bandwidth_extension
Crystality performs blind bandwidth extension but in case highly limited signals it may be not so efficient - i assume it was made for signal with moderate spectrum loss - perhaps somewhere 8 - 10kHz at least present.

[fbreve]

I didn't realize I could stack the crystality filter. I tried it for a while but my best results so far still come from Adobe Audtion alone.

Attached is the best I could get so far.

I used:
1. Normalize to -3dB.
2. FFT Filter, cutting everything below 40 Hz and above 8KHz.
3. Automatic Click Remover (limit: 30 / complexity: 16 - default settings)
4. Noise reduction with sample (20%, other options at default)
5. Multi Band Compressor (preset: Enhance Hights)
6. Mastering (preset: Bright Hype)
7. Normalize to 100%
8. Mix channels (Stereo -> Mono, no point in keeping two channels if the source is mono)

[pandy]

8. Mix channels (Stereo -> Mono, no point in keeping two channels if the source is mono)

You can capture mono with two channels then add them (stereo --> mono) - this will reduce noise by 3dB.

[fbreve]

You mean joining them as the first step?

I did that now. Results are attached.

Now it is:
1. Join two channels
2. Normalize to -3dB.
3. FFT Filter, cutting everything below 40 Hz and above 8KHz.
4. Automatic Click Remover (limit: 30 / complexity: 16 - default settings)
5. Noise reduction with sample (20%, other options at default)
6. Multi Band Compressor (preset: Enhance Hights)
7. Mastering (preset: Bright Hype)
8. Normalize to 100%

[-Habanero-]

In my experience I've found simply resampling without anti-aliasing brightens up the audio a lot better than the more sophisticated tricks I've tried. It's really only practical to replicate very high frequencies where your brain can't really tell the difference, say 22 to 44 kHz. Any replicated audio that you can sensibly hear will sound really off-key.
Here's the resampling with no anti-alias filter:

[fbreve]

I'd like to thank you all for the hints.

Attached a sample of the final result.

The recipe I used was:
1. Join two channels
2. Normalize to -3dB.
3. FFT Filter, cutting everything below 40 Hz and above 8KHz.
4. Automatic Click Remover (limit: 30 / complexity: 16 - default settings)
5. Noise reduction with sample (20%, other options at default)
6. Multi Band Compressor (preset: Enhance Hights)
7. Mastering (preset: Bright Hype)
8. Normalize to 100%

Handbrake is acting strangely with the mono audio track, though. Media info:

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 1 h 57 min
Bit rate mode : Variable
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel(s)_Original : 1 channel
Channel positions : Front: C
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 spf)
Compression mode : Lossy
Stream size : 161 MiB (4%)
Title : Mono / Mono
Default : Yes
Alternate group : 1
Encoded date : UTC 2016-07-13 11:52:49
Tagged date : UTC 2016-07-13 11:52:49

VLC Player does not like that and puts the audio on only one speaker.