Sample Rate Problems

[ChrisM]

Hi Guys,

I have a strange issue. I am able to change the sample rate of MP3s to an equivilent of -10%, but it will not let me go to +10% - I use the formula...

(pitch percentage * (44100 / 100)) + 44100

...the "44100" is determined by the "ChannelGetAttributes" procedure, which I call just before altering the playback rate.

I can change to about +9% but not +10% - I get error code 25 which is "Illegal Sample Rate". This means that if I try a sample rate of 48000 on a 44100 file it is ok, but any more than 48000 number and the error occurs.

Any suggestions? I thought the maximum was 100000?

Thanks in advance,
Chris M

[Chris]

HI

I thought the maximum was 100000

not allways
Example a Soundcard with a Chrystle Chip make only
10000 - 50000 HZ
---------------------------------------------------
but I`m afraid that your soundcard only will make a
Maximum of 48000 hz
9  % Pitching = 48059 HZ
10 % Pitching = 48510 HZ


(but the most other soundcards will make 100 - 100000 hz)


Greets Chris

PS which Soundcard do you have ??
    

[(: JOBnik! :)]

Hi

To get the Frequency to Percents you have to:

current_freq / original_freq * 100.0

e.g: 57330Hz / 44100Hz * 100% = +130%

To convert Percents to Frequency you have to:

current_percent / 100.0 * original_freq

e.g: 130% / 100% * 44100Hz = 57330Hz

Have fun!

JOBnik!

[ChrisM]

I have a Videologic SonicFury Sound Card.

Thanks for your suggestions guys. Do you know of a way to determine the sound card's maximum pitch frequency?

Thanks again,
Chris M

[Chris]

mmm  i think there must be a other Problem...
I have look
VideoLogic Systems' SonicFury

Analog (A-A):
Frequency Response: 10Hz - 120kHz (-3dB)...
maybe an error in your code ?
Greets Chris

[ChrisM]

I can't paste the code here but basically I go through this prodecure...

1) Free the stream
2) Open the MP3 File
3) Play the File
4) If successful, get the original frequency
5) Set the Cut In Point by moving the start point
6) Set the Volume, according to defaults in program
7) Set the frequency (pitch)

...and that's it. I can change the pitch to -10%, but not +10%, only about +8%, or close to that. Even if I enter the frequency manually (i.e. 48069) it doesn't work, it will only allow up to 48000.

Seems very odd

Regards,
Chris M

[Chris]

MM I think give me a email adress  and i will send to you a litte pitch demo..so we can test it
Greets
Chris

[engineeer]

Analog (A-A):
Frequency Response: 10Hz - 120kHz (-3dB)...

What you find in your card's specs is frequency responce, not sampling rate.

You card supports 8/16-bit playback and recording at up to 48 kHz (mono/stereo). So, you can't set frequency (pitch) above this value.

Some cards supports higher SR, e.g. SB Audigy - up to 192 kHz.

Also, bass help says:
"Although the standard valid sample rate range is 100 to 100000, some devices/drivers may have a different valid range. See the minrate and maxrate members of the BASS_INFO structure."

[ChrisM]

"Audio converters: Dual AC-97 2.1 audio codecs with hardware full-duplex for simultaneous record and playback and up to 48 kHz sample rates. 18-bit A/D converters for high-resolution recording. 20-bit D/A converters for high resolution playback of up to 6 independent streams."

Yeah tis true, the card only plays up to a 48kHz sample rate - which explains the problem completely.

Thanks anyway guys for all your help.

Regards,
Chris M