Jump to content
  • Who's Online   0 Members, 0 Anonymous, 13 Guests (See full list)

    • There are no registered users currently online
  • 0

Converting WMA to WAV


T-Hawke

Question

Recommended Posts

Read #9, very interesting. I have a real STUPID question after reading all of this.

 

Why is called Decoding then and why is there even a process to decode back to wav if there is no difference/ why isn't it locked. Coding means to me, that there are rules and and those rules can be read in two directions. so if that is NOT true and it seems by that author, it is NOT true, then why offer the process? Why would it not stay an MP3 and not waste memory by adding 27 mb back to it with no difference in sound..... I say there is somethingbeing left out here and you all have struck up my curiosity and I may have to do some serious reading about stuff that willprobably fly well over my head. Now is a decoder like in Winamp the same as a File Converter?? does it do the same thing? also that article is 7 years old, has anything changed with the more recent codecs? and programs it mentions winamp and the inhouse decoder etc...... :D

The "music" still needs to be decoded into a byte stream that can be fed to the D/A converters. So, the compressed music must be uncompressed to do that. All of your players do that "on the fly" as they're feeding the data to the sound card, so they're not taking up much of any extra memory, except what little they may buffer internally before feeding it to the sound card.. When you create an Audio CD, that has to be the uncompressed .WAV format of data, that's the standard if it's going to play on a non-MP3 CD player. But of course, the discarded musical data is still discarded, lost, never to be recovered.

 

And indeed, there are Coding and Decoding "rules", it's just that MP3 has always been defined as a "lossy" compression scheme, meaning that what gets decoded after encoding is NOT the same as what went in originally. Without that amount of loss, compression of a .WAV file is usually doing good to get it down to 1/2 the original size, as the Monkeys Audio compressor does. That's a lossless compression scheme, and upon decoding back to .WAV, the original, and decompressed files are identical.

 

Hope that helps!

Link to comment
Share on other sites

gi7omy

 

 

As digitail Photos still come short of 35 mm, Digitial sound still comes short of Analog. Want a good cheap source for a real decent 90 db plus dynamic Range and freq responses in the 30k range? VHS - HiFi wth the flying Auudio heads. Surpasses any reel to reel at 30 ips. :)

 

Your analogy between film and analog music is not entirely justified. The resolution of photographic film depends on the size of the grains of the photoactive material. A grain of, say, silver halide is either all converted to silver or not at all converted by a given exposure to light and in that sense film is digital, 1 or 0 for each grain. The difference is that in film the grains (or 'pixels') are randomly distributed in three dimensions (film has thickness) and have a certain size distribution, whereas in a digital camera the pixels are regularly placed in two dimensions and are all the same size. Since the grains in a film are randomly distrbuted in three dimensions and densely packed they can and do overlap when viewed from above and so if one scans across one gets what looks like a noisy analog signal, but this is really the sum of digital signals with a width distribution related to the size distribution of the grains. Scanning across a digital image, one gets step wise changes at the pixel boundaries (plus some electronic noise generated by the camera). Whether one is 'better' than the other can be considered to depend on the pixel size versus mean grain size. The better digital cameras have pixel size of the same order of magnitude as the mean grain size in typical film. The best, such as Hasselblad (with39Mp, 5412x7212 pixels) give results that are indistinguishable (except under a microscope) from those obtained with fine grained (slow speed) film. Interestingly, software such as Photoshop has filters with which one can manipulate the digital photo to reproduce the graininess of large grained film, which is considered by some photographers to be an artistic effect.

 

PS: 5412x7212 corresponds to 300PPI for a print size 18" by 24".

 

An interesting article comparing digital with 35 mm is

 

http://www.normankoren.com/Tutorials/MTF7.html

Link to comment
Share on other sites

Followed with interest what all had to say. Having been a musician in the past and using tube type Fender amps I must say there is something great about their sound that I have never heard in solid state amps. I still use a 1968 Fender Bassman amp that I bought new and its sound cannot be imitated. However I disagree with some of the comments regarding analog recordings being superior to digital.

 

If you come across a digtal recording that was recorded in a high quality studio with a sound engineer that knows what he's doing it will blow the socks off an analog recording. I have lots of examples. Some of my favorite groups were recorded years ago in analog and I wish I had digital recordings of them. (I don't mean the original analog tape put on CD) I mean a digitally mastered recording.

 

But.............some like Chevys and some like Fords.

Link to comment
Share on other sites

OK Guys, give me some education here.

 

I only record from vinyl in PCM WAV and will not use any compression mode such as MP3 etc. Now I know we are talking about data and not sine wave recording such as vinyl, Tape or radio broadcast.

My daughter has recorded all of her music to the computer in MP3 format, I was under the impression that if you converted from MP3 back to WAV that it would restore the data. Something like in the old days where they had Basic and was it compiler basic that was a compressed version that could be re expanded back into Regular basic? I can't remember exactly what it was, but do remember having to save on C-10 or C-20 cassettes and there was a utility or something that would compress the program and later if you could UNCOMPRESS. I thought converting to WAV from MP3 was an uncompression with the convertor that would restore back to full data. I guess like having a program that would remove certain letters if they were preceded or followed by other letters, and the coding was a firm rule, so when you use a convertor to uncompress, it would use the rules to uncompress. With Data there could be certain loss but when data is music maybe a note would be ommitted here and there. Was I dreaming? If not then if I have a 3 mb MP3 and I convert to WAV what is filled in to create the extra 30 mb when it becomes a WAV file?

 

 

Another way of putting it is, listening to MP3 islike putting a screen door in front of your TV and listening to or converting back to WAV is like taking the screen away. Educate me, I was going to convert my daughter's MP3 into WAV to giver better sound.. ( I am an OLD ANALOG AUDIO ENGINEER AND NOT SUPER EDUCATED IN DIGITIAL)

Link to comment
Share on other sites

Jean

 

Yes! you are right, without getting detailed I was merely trying to state that digital has yet to catch up to 35mm for quality. Your explanation on how Silver halide molecules get excited or grain or whatever to create the image is a point that may say that Digital may someday Surpass 35mm or any other single frame photo technology. I doubt this will be true in my lifetime though. When I see photos of our molecular world, I have to wonder if digital will really be able to show such minute images with such detail. Then again who would have ever thought 60 gig byte could fit in a baseball card size stereo? I surrender my example of digital to 35 mm as being a poor example.

 

Sound on the other hand is not, film is usually a max of 30 frames per second and action is always choppy, the human eye is just not able to refocus in time to see the choppiness. The Human ears on the other hand react much faster than the eye focuses and our means of recording sound is a continuous capture of the sine wave with the ability to go far above the human hearing range of 20,000 htz or for you newbies cps. Sound when using analog was not being recorded in bits but in continuous form. Digital is translating into bytes and bits and creating data from a continuous source. Will digital ever be as accurate as analog, not in a million life times. Will it get to the point that humans will not be able to detect the difference? No doubt.

 

Analog for instance had CD-4 LPs back in the 70s where it was a Descrete 4 channel and not some Haffler's idea of a sythnisized 4 channel. On an LP the rear speaker signals were buried between 32k and 70k hz and would be picked up by the styli and sent to a CD-4 Demodulator to be brought back down to Human Hearing ranges and sent to the rear speakers. A Feat I doubt Digital will ever be able to accomplish. Wait! before I get a ton of digital defenders pouncing upon me, digital many very well be able to accomplish the task using a different set of rules but rules are what I hate. Rules means the Original Source is being translated into something else and then retranslated into something to resemble what the original was. It is actually fooling us to believe we have something as good as the original and in many cases this may be true. I personnally have a trained ear and I prefer to listen to every single instrument in the band, and not mask or filter out any portions that may overlap. That to me deadens the sound and causes it to be hollow. CD is successful because it is so easy to market and has many uses in many different types of formats, from creating your own Music CDs in seconds versus hours, special effects are quick and easy, used for data, small, easily edited versus editing blocks and Splicing tape. In our recording studio our Echo chamber was a cement and wood room that had a JBL Monitor suspended from the ceiling and a Microphone suspended from the ceiling. The walls or ceiling and floor were not parellel of each other but more of a trapazoid in design. You increased echo by increasing volume and thence increase the the time the sound would reflect off the flat surfaces. Primitive but it was an accurate measurement of an actual echo, digital does it with data information, is it as good? probably to the people who enjoy Rap or Hip Hop it is awesome, to me and many people grew up with Acoustics, it is dead and sounds like it is played thru a pillow.

 

LONG LIVE ANALOG Vive Le Analog

Link to comment
Share on other sites

 

 

I knew all this already CD, I read the entire link and didn't see where it spoke of CONVERTINg. I am interested in learning about CONVERSIONS and does it or does it not through programing restore the data back. I thought it did. I thought it was a program process that created the compression, like pulling every other bit or whatever and then when restoring back to WAV, restoring every other bit. Hence a Converter Program.

 

LIKE WINZIP, you can ZIP a file to a very small size and then UNZIP it to its FULL orginal size, isn't that what converting to MP3 and Converting back to WAV does? at least i thought so...

Link to comment
Share on other sites

<snip>

Analog for instance had CD-4 LPs back in the 70s where it was a Descrete 4 channel and not some Haffler's idea of a sythnisized 4 channel. On an LP the rear speaker signals were buried between 32k and 70k hz and would be picked up by the styli and sent to a CD-4 Demodulator to be brought back down to Human Hearing ranges and sent to the rear speakers. A Feat I doubt Digital will ever be able to accomplish. Wait! before I get a ton of digital defenders pouncing upon me, digital many very well be able to accomplish the task using a different set of rules but rules are what I hate. Rules means the Original Source is being translated into something else and then retranslated into something to resemble what the original was. It is actually fooling us to believe we have something as good as the original and in many cases this may be true. <snip>

 

LONG LIVE ANALOG Vive Le Analog

Okay... and I'm only replying because I see an inconsistency in your argument about "Rules" and translation, but immediately before your complaint about "Rules", you say that CD-4 LPs had the rear channels encoded at 32Khz to 70Khz. Obviously the sound for those channels was "translated" to a higher frequency, and then it has to be decoded down to the normal audible range. So, in this example, you're hoping that the encoding and decoding of the rear channels results in something resembling what the original was. In my point of view, not that much different than the digital domain.

 

And while I'll not argue that a D/A representation of a sign wave is indeed a "stepped" approximation, when played back on a set of physical speakers, they do not respond in a digital fashion to the "steps", at least not precisely. The physical movement of the speakers will tend to filter out the steps, at the very least rounding them off, if not nearly eliminating them.

 

But, I argue for arguments sake.

 

The definition of "bad music"? Music someone else likes.

Link to comment
Share on other sites

The problem is that as mp3 compresses the files, it does so by discarding some of the frequencies. It's not like zip where the data is just compressed but more like peeling off layers

 

Unfortunately, the layers having been peeled off, there's no way to put them back - when they're gone, they're gone

Link to comment
Share on other sites

The problem is that as mp3 compresses the files, it does so by discarding some of the frequencies. It's not like zip where the data is just compressed but more like peeling off layers

 

Unfortunately, the layers having been peeled off, there's no way to put them back - when they're gone, they're gone

 

are you sure? I thought that is what the job of the codecs was..... I really was under the impression that with the codecs and the convertor software, all was restored. If I convert back to WAV from MP3 what is the extra 30 meg a byte? The MP3 before conversion is 3 meg and after converting to wav, the wav file is 30 mb...... I am confused or misinformed.

 

Pony let's say during conversion I take a base note of 120 cps.. Now I have a peak and I have trough. If I delete the bulk of the climb and the descend of the sine wav and keep the low point and the high point as reference, then when I convert to MP3 that is what I am doing, yes No? and when I convert back to WAV, I bridge the climb and descend with data?? or something like that.... so I can peel it off and then I can put it back, all with a program that has the process rules. Kinda like taking shorthand and with the rules known, I can take the short hand and create long hand with no loss of info. When playing the MP3 it will not sound as good as WAv, due to misisng data but when convert back to WAV, it would be like reading the short hand converted back to longhand or is this all hopeful thinking, I have never converted from MP3 to WAv yet but guess I need to experiment.

Link to comment
Share on other sites

I got this quote from this website:

 

"Decoding to .wav does not improve sound quality. Most importantly, it does not give you the same .wav that the original mp3 was created from. Mp3 encoding is a lossy process - audio information is lost that can never be put back. Mp3 decoding does not put any data back - it takes a very compressed file format, and converts it into the audio data that the file represents. However, the audio data that was thrown away during the encoding process is not magically returned. The decoded wav file is much larger than the mp3, but it holds the same information. The original wav file contained much more audio information."

Link to comment
Share on other sites

OK - simple article here, but basically what it does is to discard notes that aren't heard as well as others - say two notes being played simultaneously by a violin and a trumpet - obviosly, the trumpet note drowns out the violin one, so the violin note is discarded during compression. Now, having been dumped in the garbage and not recorded, it can't be brought back (it literally is gone).

 

So if you try to convert the mp3 back to wav - you only get the tones that were saved - the ones lost in compression stay lost

Link to comment
Share on other sites

I got this quote from this website:

 

"Decoding to .wav does not improve sound quality. Most importantly, it does not give you the same .wav that the original mp3 was created from. Mp3 encoding is a lossy process - audio information is lost that can never be put back. Mp3 decoding does not put any data back - it takes a very compressed file format, and converts it into the audio data that the file represents. However, the audio data that was thrown away during the encoding process is not magically returned. The decoded wav file is much larger than the mp3, but it holds the same information. The original wav file contained much more audio information."

 

 

WoW! somewhere I picked up wrong input.... Interesting, where was this quoted from? is there more to go with it so I can read it and get educated?

 

OK - simple article here, but basically what it does is to discard notes that aren't heard as well as others - say two notes being played simultaneously by a violin and a trumpet - obviosly, the trumpet note drowns out the violin one, so the violin note is discarded during compression. Now, having been dumped in the garbage and not recorded, it can't be brought back (it literally is gone).

 

So if you try to convert the mp3 back to wav - you only get the tones that were saved - the ones lost in compression stay lost

 

 

So loss of Harmonics........ I know that WAV saves the silence as well as the noise and thought silence between notes was ommitted in WAv to MP3 conversion or whatever, not really sure. But also thought the Codecs had the rules embedded and the converter program used rules and codecs to ensure all wa sput back or bulk was put back.... I guess it is time to do more reading...... shame shame, I knew Analog like the back of my hand and digitial well, I guess Ifeel asleep during that class.

 

 

gi7omy

from the link you posted

"Compressing the rest of the song with well-known compression techniques shrinks the song considerably -- by a factor of 10 at least."

 

Well known compression techniques but no where in al of the pages does it say that these techniques are NOT reversed when convertingback to WAV. I can see where the first part about the loud band covering the other bands of less volumn would not be restored, possibly but it is the other part about the 10 times with known techniques. So converting back to WAv would not be as good as the original wav but better than the mp3 that was converted from the orginal wav. YES?????

Link to comment
Share on other sites

I grew up with analogue and found I liked digital better (just as well because the bottom fell out of the TV repair business but by that time I'd made the switch and was able to move away

 

Ahh the days of Class A amps with a pair of high power pentodes feeding into big speakers :lol:

 

But, still with mp3 > wav, as a song has it here "What's done is done and what's lost is gone and lost forever"

Link to comment
Share on other sites

I grew up with analogue and found I liked digital better (just as well because the bottom fell out of the TV repair business but by that time I'd made the switch and was able to move away

 

Ahh the days of Class A amps with a pair of high power pentodes feeding into big speakers :lol:

 

 

24LQ6s matched pair, McIntosh amps..... Soundcraftsman had Class H amps, weren't consuming FULL Power with soft passages as Class A did, much more efficient. Rare too. I prefer Analog for there is no loss and the harmonics are there. Take an Acoustic recording on LP like maybe Norman Blake and his Guitar and play it and you will hear notes lingering in the air after the note is played on the string....harmonics, or take a Banjo and play a light string on the 17th fret and listen to it on Analog and then on Digital Big Difference. CD is cut and dry, no harmonics, no lingering notes. Digital is much easier to edit and mix etc but doesn't have the sound quality through my Cerwin Vega U 15s that analog has.....

Link to comment
Share on other sites

I do remember drooling over a rig I had in for repair - twin PL81s (line output pentodes for TV sets) in Class A - those babies need 500V on the top caps to run efficiently - the whole thing nearly needed a fork lift to get it on my bench (well I was younger and fitter back then) Nowadays, I'm pushing 100W RF from a Yaesu rig that's no bigger than the average car radio. At least them old bottles kept the place warm when they started to draw the power :lol:

Link to comment
Share on other sites

Yep,click on the link and it will take you to the page.

 

 

Read #9, very interesting. I have a real STUPID question after reading all of this.

 

Why is called Decoding then and why is there even a process to decode back to wav if there is no difference/ why isn't it locked. Coding means to me, that there are rules and and those rules can be read in two directions. so if that is NOT true and it seems by that author, it is NOT true, then why offer the process? Why would it not stay an MP3 and not waste memory by adding 27 mb back to it with no difference in sound..... I say there is somethingbeing left out here and you all have struck up my curiosity and I may have to do some serious reading about stuff that willprobably fly well over my head. Now is a decoder like in Winamp the same as a File Converter?? does it do the same thing? also that article is 7 years old, has anything changed with the more recent codecs? and programs it mentions winamp and the inhouse decoder etc...... :D

 

I do remember drooling over a rig I had in for repair - twin PL81s (line output pentodes for TV sets) in Class A - those babies need 500V on the top caps to run efficiently - the whole thing nearly needed a fork lift to get it on my bench (well I was younger and fitter back then) Nowadays, I'm pushing 100W RF from a Yaesu rig that's no bigger than the average car radio. At least them old bottles kept the place warm when they started to draw the power :lol:

 

 

Tubes had so much heat loss (energy) versus solid state, but the sound quality from a tube is so much more better than solid state. But solid state has marketing in its favor because there is little or no maintenance such as runningdown to the local Tube Tester every year or so, having a well vented area for the heat dissipation versus solid state just build it into the walls. loved my tube sets though... Macs, Carver, Heathkit etc etc

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...