Hi y'all !
I downloaded a song - "Under The Bombs" from Think Twice - from the goodies section of F-Communications. Unfortunately it sounded a bit dull and I noticed that the encoder which has been used to encode this 128kbps file limited the bandwidth to 14 kHz.
So, this is what I did:
- Opened MP3 in Cool Edit (window #1)
- copied the whole track (window #2)
- applied an FFT bandpass filter: 10-12 kHz
- created new window (window #3)
- generated a full-scale sine on both channels with a frequency of 4000 Hz and a duration of 360 seconds (window #3)
- copied this sine (window #3) to the clibboard
- switched to window #2 and set the pointer to 00:00
- Edit -> Mix Paste -> Modulate with Clibboard
- FFT highpass filter at 13 kHz (window #2)
- copied current wave to clibboard (window #2)
- switched to window #1 and set the pointer to 00:00
- Edit -> Mix Paste -> Overlap (Mix) with Clibboard
Et voila. I shifted the 10-12 kHz content to 14-16 khz and mixed it with the original. "Manual subband replication" so to speak. The result sounds much better.
A "before/after" example is attached to this message (600 KB).
have fun,
Sebastian
edit: fixed a typo
Full Version: Manual SBR
Interesting... For those of us who are less technical, is there a less complicated way to generate harmonics? It does seem to improve the sound. Subjectively anyway.
Would it be possible to create an impulse from the process you did?
QUOTE(woody_woodward @ Sep 29 2004, 07:59 AM)
Interesting... For those of us who are less technical, is there a less complicated way to generate harmonics? It does seem to improve the sound. Subjectively anyway.
Well, this is only a hack. The content is shifted exactly 4 kHz upwards which is likely to fail in restoring harmonics at the correct multiple of the fundamental frequency. But in case of the quite noisy percussions it works.
I don't know if there is a less complicated way to do this. (I think not)
Sebastian
QUOTE(dev0 @ Sep 29 2004, 08:12 AM)
Would it be possible to create an impulse from the process you did?
An impulse response ?
No, you cannot shift a frequency band up/downwards via a convolution.
Sebastian
Interesting!
Is the "high frequency reconstruction" method used by NCTU MP3 decoder a similar one?
Is the "high frequency reconstruction" method used by NCTU MP3 decoder a similar one?
QUOTE(Sunhillow @ Sep 29 2004, 12:17 PM)
Interesting!
Is the "high frequency reconstruction" method used by NCTU MP3 decoder a similar one?
Is the "high frequency reconstruction" method used by NCTU MP3 decoder a similar one?
From what I can tell is the NTCU HF reconstruction system extrapolating the log frequency envelope - which seems to be more sophisticated than this hack. But I'm actually not aware of how they compute the samples they put under this envelope.
The effect is similar, though (since it creates new content above the original cut-off frequency)
Sebastian
Hi,
How to open the msbr-before and msbr-after (.OCG) files
Regards
How to open the msbr-before and msbr-after (.OCG) files
Regards
QUOTE(SebastianG @ Sep 29 2004, 09:14 PM)
Hi y'all !
I downloaded a song - "Under The Bombs" from Think Twice - from the goodies section of F-Communications. Unfortunately it sounded a bit dull and I noticed that the encoder which has been used to encode this 128kbps file limited the bandwidth to 14 kHz.
So, this is what I did:
- Opened MP3 in Cool Edit (window #1)
- copied the whole track (window #2)
- applied an FFT bandpass filter: 10-12 kHz
- created new window (window #3)
- generated a full-scale sine on both channels with a frequency of 4000 Hz and a duration of 360 seconds (window #3)
- copied this sine (window #3) to the clibboard
- switched to window #2 and set the pointer to 00:00
- Edit -> Mix Paste -> Modulate with Clibboard
- FFT highpass filter at 13 kHz (window #2)
- copied current wave to clibboard (window #2)
- switched to window #1 and set the pointer to 00:00
- Edit -> Mix Paste -> Overlap (Mix) with Clibboard
Et voila. I shifted the 10-12 kHz content to 14-16 khz and mixed it with the original. "Manual subband replication" so to speak. The result sounds much better.
A "before/after" example is attached to this message (600 KB).
have fun,
Sebastian
edit: fixed a typo
I downloaded a song - "Under The Bombs" from Think Twice - from the goodies section of F-Communications. Unfortunately it sounded a bit dull and I noticed that the encoder which has been used to encode this 128kbps file limited the bandwidth to 14 kHz.
So, this is what I did:
- Opened MP3 in Cool Edit (window #1)
- copied the whole track (window #2)
- applied an FFT bandpass filter: 10-12 kHz
- created new window (window #3)
- generated a full-scale sine on both channels with a frequency of 4000 Hz and a duration of 360 seconds (window #3)
- copied this sine (window #3) to the clibboard
- switched to window #2 and set the pointer to 00:00
- Edit -> Mix Paste -> Modulate with Clibboard
- FFT highpass filter at 13 kHz (window #2)
- copied current wave to clibboard (window #2)
- switched to window #1 and set the pointer to 00:00
- Edit -> Mix Paste -> Overlap (Mix) with Clibboard
Et voila. I shifted the 10-12 kHz content to 14-16 khz and mixed it with the original. "Manual subband replication" so to speak. The result sounds much better.
A "before/after" example is attached to this message (600 KB).
have fun,
Sebastian
edit: fixed a typo
QUOTE(subbu123ic @ Dec 7 2004, 02:43 AM)
Hi,
How to open the msbr-before and msbr-after (.OCG) files
Regards
How to open the msbr-before and msbr-after (.OCG) files
Regards
Those files with the ".ogg" extension are Ogg Vorbis files.
It's among others an alternative to MP3.
I'm sure there's an Ogg Vorbis plugin for your audio player of choice. (For WinAMP there is for sure) You might also want to try out the Foobar2000 player. It has built-in support for a large amount of various formats (among other nice features)
SebastianG
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