Audio Codecs: What is Ssrc?

vhelp · #1 07-21-2003, 07:38 PM

Hi AudioFile lovers and all

I posted this here because I couldn't find a home for it

Anyways..

SSRC v1.29 ...
that is my question. I did a google search and did a "tad" bit of
reading on it, but I'm still a bit confused as to it's use and benefit.. and
maybe even worth adding it to my GUI app. Anyways..

My question is like this:

* who would use it, and why ??
* what benefits are there to using it ??
* when would you use it ??
* anything else ta add here ??

Below, is a snip from the website (vie google) I capped here for those that
are in the dark as well.

Thanks,
-vhelp

FROM: http://www.afterdawn.com/software/au...tools/ssrc.cfm

Quote:

This program converts sampling rate of PCM wav file. Also, this program has a function to apply dither to its output and extend perceived dynamic range. Sampling rates of 44.1kHz and 48kHz are populary used, but ratio of these two frequency is 147:160, and it's not a small numbers. Therefore, sampling rate conversion without degradation of sound quality requires filter with very large order, and it's difficult to achive both quality and speed. This program achived relatively fast and high quality with two different kinds of filters combined skillfully.

Dialhot · #2 07-22-2003, 04:22 AM

Quote:

Originally Posted by vhelp

* who would use it, and why ??

This tool is used to downsample a audio track from 48Khz to 44.1Khz.
It is internally called by Headache or Besweet when you ask them to do such work !

Quote:

* what benefits are there to using it ??

48 Khz is the rate used for DVD, 44.1 is the normal samplerate for a (S)VCD. Some players don't read (S)VCD with 48Khz audio track so you have to do the downsampling when you encode from a DVD.

Quote:

* when would you use it ??

See above.

Quote:

* anything else ta add here ??

Why do no-one used it directly ? Because everyone (I guess) use Headache or Besweet to do the job.

vhelp · #3 07-22-2003, 05:28 PM

Thanks Dialhot

Ok, so it's used for down-sampling your 48k to a 44.1k

.
.
and, it besweet and headac3 use "their own method" of down-sampling..
(not SSRC, right?) and as such, it's just another app (tool) to down-sample
audio. Ok. then. i think I understand.

I was asking these question, because I thought that I was deciding on
weather to include this feature in my GUI app for bbMPEG I'm currently
working on (or to build s small GUI for the heck of it, since it's a command
line version, and just for the challege of creating stuff

) and it seems that
bbMPEG does not include a down-sampling feature. I'm just trying to
figure out the logic behind it all, and determine if I should include it.

Well, I'll look into it further. Any other input you can share, I would love
hearing (reading, that is)

Thanks again for your detailed response - much appreciated

all the best,
-vhelp

Dialhot · #4 07-23-2003, 03:47 AM

Quote:

Originally Posted by vhelp

and, it besweet and headac3 use "their own method" of down-sampling..
(not SSRC, right?) and as such, it's just another app (tool) to down-sample
audio. Ok. then. i think I understand.

You just misread me

. I said "It is internally called by Headache or Besweet when you ask them to do such work". That means that these tools use ssrc, but via a dll, not the external ssrc.exe.

Quote:

and it seems that
bbMPEG does not include a down-sampling feature.

But... bbmpeg is just a muxing tool

It doesn't provide anything to encode audio nor video. And so, that's normal to don't have any DS tool.

vhelp · #5 07-23-2003, 07:14 PM

@ Dialhot..

Quote:

You just misread me . I said "It is internally called by Headache or Besweet when you ask them to do such work". That means that these tools use ssrc, but via a dll, not the external ssrc.exe.

ok, thanks for clearing that up.

-vhelp