Merging all tracks in one - Foobar file shorter duration than Audacity

[jfjfjf]

Single 3 tracks (320 mp3):
1 - 04.43.011
2. 02.23.125
3. 24.27.768

Merged track (320 mp3)
Foobar2000: 31.33.747
Audacity: 31.33.904

Why?

I didn't find anything similar on the forum.
I thank in advance anyone who can take care of my question

[El Heggunte]

Single 3 tracks (320 mp3):
1 - 04.43.011
2. 02.23.125
3. 24.27.768

Merged track (320 mp3)
Foobar2000: 31.33.747
Audacity: 31.33.904

Why?

Wild guess: Foobar2000 uses/considers «gapless playback» and Audacity does not

[hello_hello]

I think El Heggunte is correct, and the individual durations didn't come from fb2k.

All lossy codecs add silence to the beginning and end of the audio. Gapless playback means the silence is skipped (the gapless information is stored in the file). Any duration displayed by fb2k excludes the extra silence.

fb2k has a UI element called "Selection Properties". If you add it to the GUI somewhere (assuming it's not already) it displays various information about audio files. under "General" it displays the duration. If you select multiple files, the total duration is shown.

I merged three tracks after first checking their total durations, and then compared that to the duration of the output MP3. I also merged them as a wave file because there's no padding for wave files, and as you can see by the screenshots.....

Try starting with wave files. Check their individual durations and merge them while outputting a wave file. Do the same for both fb2k and Audacity. Hopefully they'll agree, which would mean for some reason Audacity doesn't ignore the MP3 padding, and/or there's no gapless information saved to the output file.

Edit: I just remembered fb2k also displays the encoder padding, although it seems only for MP3, and it may depend on the encoder used. I'm guessing, but I assume the first number is padding at the beginning, the second is the end padding, and guessing once again, the numbers probably refer to the number of samples. Milliseconds wouldn't make sense, but they might mean something else in computer-speak.

[hello_hello]

By the way, you can combine MP3s without re-encoding them using MP3DirectCut. I think you need to open an instance of MP3Directcut for each MP3, then you can highlight the entire contents of the second MP3DirectCut, copy it, and paste onto the end of the first MP3 etc.

I can't remember how MP3DirectCut handles any gapless information when opening an MP3 as it's not the sort of thing I generally have to care about when using it, but you can edit MP3s, the process is lossless, and you can save the combined MP3s as a single file.

It can also be used for AAC.

[jfjfjf]

Guys!
In fact, when it comes to the music collection - and this is the case - I give absolute preference to "lossless. It happens that sometimes I only have "lossy" material, and when merging mp3 tracks casually I noticed the difference between Audacity and Foobar2000 - a difference that I had already observed NOT occurring when dealing with flac files.
Obviously this is a minor issue in a forum as categorized as VideoHelp, but it left me quite intrigued...
I did not expect such attention. I learned a lot. I thank all of you who took care of my question.
Apologizing for my bad practice of the English language, I send you my regards from Brazil!