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: APE vs FLAC (Read 14597 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

APE vs FLAC

I download songs in APE format and transcode into FLACs to be used on my rockboxed iPod. So today I was curious to see the difference between these two formats so I did an ABX test on foobar. And to my surprise I could hear a difference between the two!! 4/4 times is not just by guessing I guess. However from my understanding, transcoding from a lossless format to another should not cause quality degradation. To my ears the APEs sound cleaner, smoother than the FLACs, a much bigger difference between APE and LAME VBR because I always have a hard time distinguishing between the two.

FYI, I use foobar with FLAC 1.1.2 codec to transcode the songs.

Any idea why this is happening?? 

APE vs FLAC

Reply #1 –
Option #1: you didn't hear anything different, you only think you did.

Option #2: you don't know how to do a proper ABX.

Option #3: you screwed up the transcoding.

There isn't really much else to say, the decoded soundfiles are bit-for-bit identical.  There are no differences.

APE vs FLAC

Reply #2 –
Quote from: Curtor on
Option #1: you didn't hear anything different, you only think you did.

Option #2: you don't know how to do a proper ABX.

Option #3: you screwed up the transcoding.

There isn't really much else to say, the decoded soundfiles are bit-for-bit identical.  There are no differences.


Answer to Option #1: I got 4/4 on the ABX test, I don't think I didn't hear no difference...
Answer to Option #2: I believe doing the ABX test on foobar is simple enough for anyone with even a little intelligence.
Answer to Option #3: How could I possibly screwed up the transcoding? Please explain.

Thanks though, I believe there is no difference theoratically, but I do hear a difference in reality, and this has been confirmed in the ABX test on foobar.

APE vs FLAC

Reply #3 –
Quote from: derek8555 on
Answer to Option #1: I got 4/4 on the ABX test, I don't think I didn't hear no difference...
Answer to Option #2: I believe doing the ABX test on foobar is simple enough for anyone with even a little intelligence.
Answer to Option #3: How could I possibly screwed up the transcoding? Please explain.

Thanks though, I believe there is no difference theoratically, but I do hear a difference in reality, and this has been confirmed in the ABX test on foobar.

I guess you need to consider that statement.  You know there's no difference but you hear a difference?  4 samples isn't much of a field for one thing; and it certainly doesn't confirm a difference.

APE vs FLAC

Reply #4 –
Quote from: derek8555 on
I download songs in APE format and transcode into FLACs to be used on my rockboxed iPod. So today I was curious to see the difference between these two formats so I did an ABX test on foobar. And to my surprise I could hear a difference between the two!! 4/4 times is not just by guessing I guess. However from my understanding, transcoding from a lossless format to another should not cause quality degradation. To my ears the APEs sound cleaner, smoother than the FLACs, a much bigger difference between APE and LAME VBR because I always have a hard time distinguishing between the two.

FYI, I use foobar with FLAC 1.1.2 codec to transcode the songs.

Any idea why this is happening?? 


I think you should do a more extensive test than just 4/4 to find out. If you really can hear a difference and can do 20/20 in an ABX test there are only two possibilities

1. There is a bug in the software you are using.
2. You are very very very lucky.

Saying you can hear a difference between two lossless encoders is similar to saying you can see a difference between two pictures, which have been compressed/uncompressed with zip and rar. It's lossless, there should not be any differences, unless there's a bug somewhere.

/Kef

APE vs FLAC

Reply #5 –
make sure the files are bit-identical, foobar2000 has a bit comparer to do so.
If they are, then you're hearing things (and you need more than four tries for an ABX, try 10 or more), or either the APE decoder or FLAC decoder is screwed up.

If they aren't, there's either a bug, or something being applied to the audio.

APE vs FLAC

Reply #6 –
Like others have said, it is nonsensical to say you can hear a difference between 2 lossless encodings.

And, 4/4 on foobar is nothing.  Just playing around, I've gotten more than that to match just on pure luck.  You must realize each time you have a 50% chance of getting it right.  So, even for 2 indistinguishable samples, as your number to test cases goes to infinity, your success rate should go to 50%, not 0%.  Therefore, it is my opinion that if you really can hear a difference, you should be getting at least 98 of 100 correct.

APE vs FLAC

Reply #7 –
Any chance that replaygain or something similar is being applied to one format, but not the other, on playback?

-brendan

APE vs FLAC

Reply #8 –
Quote from: bhoar on
Any chance that replaygain or something similar is being applied to one format, but not the other, on playback?

-brendan


Hey, no replaygain or anything. I just did a binary comparison and result turned to be negative so could just be my ears (I doubt it.. o.O) or the decoder.

APE vs FLAC

Reply #9 –
I've never understood how something can sound "cleaner" or "smoother".

Anyway, as has been said, you must be doing something far wrong when transcoding if MP3 is transparent to you while a lossless format is not! How are you performing the conversions?

Quote
I just did a binary comparison and result turned to be negative so could just be my ears (I doubt it.. o.O) or the decoder.

Do you mean that foobar2000 indicated differences between the two "lossless" files?

APE vs FLAC

Reply #10 –
Quote from: derek8555 on
Quote from: bhoar on

Any chance that replaygain or something similar is being applied to one format, but not the other, on playback?

-brendan


Hey, no replaygain or anything. I just did a binary comparison and result turned to be negative so could just be my ears (I doubt it.. o.O) or the decoder.


Just do an extensive ABX test then.   

/Kef

APE vs FLAC

Reply #11 –
Quote from: bhoar on
Any chance that replaygain or something similar is being applied to one format, but not the other, on playback?

-brendan


Yes, one could have the RG tag while the other doesn't, though I don't know if the ABX component actually uses RG tags when decoding.

APE vs FLAC

Reply #12 –
Quote from: derek8555 on
Hey, no replaygain or anything. I just did a binary comparison and result turned to be negative so could just be my ears (I doubt it.. o.O) or the decoder.

For the binary comparison foobar has to use the ape and flac decoder. So these things are alright.
Just go into another abx session and use 10 trials or more.
lame3995o -Q1.7 --lowpass 17

APE vs FLAC

Reply #13 –
derek8555 where are you able to download ape files from?

APE vs FLAC

Reply #14 –
Quote from: halb27 on
Quote from: derek8555 on

Hey, no replaygain or anything. I just did a binary comparison and result turned to be negative so could just be my ears (I doubt it.. o.O) or the decoder.

For the binary comparison foobar has to use the ape and flac decoder. So these things are alright.
Just go into another abx session and use 10 trials or more.

4/4 (4 correct out of 4 trials) has a p-value of 0.064. There's a 6.4% possibility that your results were due to chance. That doesn't look very high, but let's assume you did one more trial and got 4/5; the p-value jumps to 0.186, making it 18.6% likely that you were just lucky.

http://ff123.net/abx/abx.php

So I agree, some more trials would be better.

APE vs FLAC

Reply #15 –
Quote from: derek8555 on
I download songs in APE format and transcode into FLACs to be used on my rockboxed iPod. So today I was curious to see the difference between these two formats so I did an ABX test on foobar. And to my surprise I could hear a difference between the two!! 4/4 times is not just by guessing I guess. However from my understanding, transcoding from a lossless format to another should not cause quality degradation. To my ears the APEs sound cleaner, smoother than the FLACs, a much bigger difference between APE and LAME VBR because I always have a hard time distinguishing between the two.

FYI, I use foobar with FLAC 1.1.2 codec to transcode the songs.

Any idea why this is happening?? 


You could try decoding both files to wav and then trying the test with the wav files. If you can't hear a difference, then any differences you have 'heard' before are due to either chance or some difference in the playback decoding (e.g. volume).

-Audio Spyder

APE vs FLAC

Reply #17 –
Hardware error?

I have seen a computer, that worked normally for six months with normal applications and Ogg Vorbis files. Then the user decided to use lossless audio. APE files played perfect. FLAC files sometimes got a glitch. Turns out the mainboards chipset was overheating.

APE vs FLAC

Reply #18 –
I am still not sure whether:

Quote
I just did a binary comparison and result turned to be negative

. . . infers that foobar2000 indicated differences or not.

APE vs FLAC

Reply #19 –
Quote from: dv1989 on
I am still not sure whether:

Quote
I just did a binary comparison and result turned to be negative

. . . infers that foobar2000 indicated differences or not.

Yes I've been wondering exactly the same thing since the original poster said that. Negative simply implies that it was the opposite of either what he expected or what he was trying to demonstrate. So if he was tring to demonstrate that they were identical then "negative" would mean they were different, but if he was trying to demonstrate that they were different then "negative" would indicate that they were identical. So it seems that we need to be able to read dereks mind in oder to make any sense of what he says. Acually that's a little similar to trying to get directions to somewhere from my wife.