I've got a couple of questions regarding ID3v2 support in pcutmp3:
Unfortunately, metamp3 doesn't tell me anything about the padding size. Anybody?
You might want to try mp3packer. It will let you do many operations to the file, all lossless. Here is an example of extracting information. is this padding information the information that you are looking for?
Info
By specifying the -i option, the program will print data about the input file then exit. No files will be written and the output (if given) will be ignored. Example printout:
*** "test/APS.mp3"
INFO:
MPEG1 layer 3
21687 frames
44100 Hz
38.281250 frames per second
566.517551 seconds
12514543 bytes in file (176.722405 kbps)
12514126 bytes in MP3 frames (176.716516 kbps) = current bitrate
93784923 bits of payload data (165.546368 kbps)
11732617 bytes of payload data (165.680544 kbps)
76013 bits wasted from partially-full bytes (0.134176 kbps)
12513349 bytes of MP3 data (176.705544 kbps) = minimum bitrate possible
777 bytes of padding (0.010972 kbps)
417 bytes outside MP3 frames (0.005889 kbps)
1 sync error
Bitrate distribution:
32: 9,0
128: 3641,0
160: 7691,0
192: 6700,0
224: 2736,0
256: 785,0
320: 125,0
Largest frame uses 8478 bits = 1060 bytes = 324.548437 kbps
Smallest bitrate for CBR is 256
It will let you remove all padding.