Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: How to defer signal degradation further? (Read 4302 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

How to defer signal degradation further?

Morning gentlemen (and ladies)

I have an odd question (as a new member) that I can't seem to find the answer to. Oddly, am not sure how to define it properly either... So I'll apologize now if I'm using incorrect terms, and/or missing the obvious.

Here's the scenario:

Recording a streamed signal from the web (let us say 320kbps for the sake of this question) in real time.... I am currently using an M-Audio Delta 24/96 soundcard in a PC, and using the digital output of this card linked to a digital input on my amplifier to monitor/listen. Equipment is partly irrelevant I imagine.

I am using Soundforge 9 to record the signal in real time. By default, I believe Soundforge will record at *44.1/16.

Here comes the confusion; the original signal was a 320kbps streamed, which at this point is now recorded as a temporary file by Soundforge as a *WAV file. I say temporary as I can choose at this point to save it as another particular format....

And here lies my confusion (stupidity?); if I chose to save it as an MP3 of 320kbps (same as the original streaming), rather than as a WAV, will there be signal degradation? I would think there is, but am seeking clarification on the matter.

i.e. Would I in effect be making a lossy copy of an already lossy signal?

Have I even made sense here? Am hoping so..... 


How to defer signal degradation further?

Reply #1 –
Quote from: Speranza on
And here lies my confusion (stupidity?); if I chose to save it as an MP3 of 320kbps (same as the original streaming), rather than as a WAV, will there be signal degradation? I would think there is, but am seeking clarification on the matter.


Yes, mp3 is a lossy format.  Saving anything at all into it will loose information, although with a good encoder and high bitrate the loss is generally more theoretical then actual.  It doesn't matter if the source already was degraded by some other encoder in the past.  The errors compound. 

How to defer signal degradation further?

Reply #2 –
Thank you for the reply!

Point taken regarding the encoder and high bit rate. So the only way to keep the original streamed signal would be to record as a WAV file, or FLAC? Are there different types of FLAC quality ?

How to defer signal degradation further?

Reply #3 –
FLAC is always lossless, no matter what compression level you use (level 9 gives you smaller files, but it takes a little longer to encode and read)

Level 5 (default) works perfect for me.

How to defer signal degradation further?

Reply #4 –
To preserve the original quality, you can either keep the WAV file, compress it to a lossless format like FLAC, or instead of recording the decompressed audio, use packet capture software to log the original MP3 file as it is streamed to your computer.

How to defer signal degradation further?

Reply #5 –
Quote from: Speranza on
Have I even made sense here? Am hoping so..... 


You could capture the original encoded raw stream and save it directly to 320kbps mp3. No need to decode it. I guess there are programs which allow to do this.

How to defer signal degradation further?

Reply #6 –
The ideal solution is to use one of the stream ripping softwares out there and save the original stream as it comes in, no transcoding at all.
Creature of habit.

How to defer signal degradation further?

Reply #7 –
Xire and Soap, thanks for the replies.

You're both hinting at the same approach, which I've looked since looked into. However, how do these work? There is software called Replay Music which purportedly does this, but is that not the same as me recording the raw stream?

Taken from the Replay Music website - "Capture Music from any Web Site or PC Software by recording it."

This has possibly confused me more!      I guess I don't understand how their own software (assuming it can) captures the raw streams and saves them as MP3s at original resolution if I cannot do this with other software such as Soundforge....

Does anyone else have those days where they can't grasp something that probably seems so obvious? 

How to defer signal degradation further?

Reply #8 –
Quote from: Speranza on
but is that not the same as me recording the raw stream?

You mix terminology here. The "raw stream" is ENCODED MP3 data. So-called stream-rippers directly save this data without any processing, thus reconstructing the MP3 file from the server.

When you record the DECODED audio signal sample by sample, you cannot reconstruct the original MP3 any more, because even re-encoding the recording with the exact same settings won't recreate the MP3 file from the server, but just add more encoding artefacts.

How to defer signal degradation further?

Reply #9 –
Replay Music is for ripping a sequence of individual songs out of streams and saving them to your HDD, properly tagged. Very clever, but it doesn't always work very well, and you should go and buy the CDs instead.

Replay Media Catcher is for grabbing entire streams without re-encoding. Depending on the stream format, you might need to demux/remux what it grabs - either automatically (if RMC supports it), or with another utility. Works pretty well. Though version 4 seems over complicated IMO. You can still get previous versions.

Cheers,
David.
 

How to defer signal degradation further?

Reply #10 –
Quote from: ojdo on
Quote from: Speranza on
but is that not the same as me recording the raw stream?

You mix terminology here. The "raw stream" is ENCODED MP3 data. So-called stream-rippers directly save this data without any processing, thus reconstructing the MP3 file from the server.

When you record the DECODED audio signal sample by sample, you cannot reconstruct the original MP3 any more, because even re-encoding the recording with the exact same settings won't recreate the MP3 file from the server, but just add more encoding artefacts.



Quote from: 2Bdecided on
Replay Music is for ripping a sequence of individual songs out of streams and saving them to your HDD, properly tagged. Very clever, but it doesn't always work very well, and you should go and buy the CDs instead.

Replay Media Catcher is for grabbing entire streams without re-encoding. Depending on the stream format, you might need to demux/remux what it grabs - either automatically (if RMC supports it), or with another utility. Works pretty well. Though version 4 seems over complicated IMO. You can still get previous versions.

Cheers,
David.



Thank you both very much, it makes sense now! I was indeed getting confused with my terminology. Now that I understand the difference, I might look at Replay Media Catcher as a demo to see if there is a substantial difference between a) grabbing the entire stream and b) recording it sample by sample with the encoded artefacts  as a downside.

PS Replay Music wouldn't be of benefit then as it doesn't do anything different to Soundforge aside from TAGGING Mp3s, which isn't why I'm looking into this whole situation originally.


Thank you to all for your help. This is an extremely helpful forum, and I hope to stay and learn more.

Cheers to all, Speranza.