Same mp3 files with slightly different tags do not produce the same sum

[Uģis Ģērmanis]

The 2 offending files in a zip file: https://dl.ugjka.net/sumtest.zip

Code:

package main

import (
	"fmt"
	"os"

	"github.com/dhowden/tag"
)

func main() {
	f, _ := os.Open("test.mp3")
	f2, _ := os.Open("test2.mp3")
	fmt.Println(tag.Identify(f))
	fmt.Println(tag.Sum(f))
	fmt.Println(tag.Identify(f2))
	fmt.Println(tag.Sum(f2))
}

Output:

ID3v2.3 MP3 <nil>
533abd81b8664e1371f7013f6453d2cce5ed28f5 <nil>
ID3v2.3 MP3 <nil>
741efd6ba8e88a3d1278160b952ac4b634edc684 <nil>

[Mattias Wadman]

There is something fishy going on in sizeToEndOffset https://github.com/dhowden/tag/blob/master/sum.go#L102 used by SumID3v2 . The seeking seems to be wrong somehow, not sure i understand how that function i suppose to be used

[Uģis Ģērmanis]

I'm pretty sure this is abandoned project.
I forked the project and there are so many things wrong

I also found out that Google Music mp3 files also have APEv2 tags at the end of file which messes up even my own fixed check-summing.

I think I will try to figure out how to extract just the codec data and checksum that

[Mattias Wadman]

Mm not much activity so a fork fixing and collecting fixes from various other forks would be great

[David Howden]

Yeah, apologies. I haven't had spare time to test/merge changes lately.

The "Sum" functionality was only implemented to de-dupe my own collection of mp3/m4a etc files so was designed/tested on those. It's likely there are bunch of problems.

I'm hope to have some time in the next few weeks to go through the issues and tidy up some of the problems.

[Mattias Wadman]

@dhowden No worries. For my use case the package is working great so many thanks!