Make non-gapless MP3 files gapless without re-encoding?

[afruff23]

I have certain MP3 files which are not LAME encoded (or are encoded with an older LAME) so they are not gapless. As I understand it, LAME mp3 files are gapless because they write a certain header which provides an accurate measurement of a song's length. Gapless can only be achieved on platforms which read this header. Is there a way to add this header to certain mp3 files without re-encoding?

[arrow224]

Use a cross-fade setting?

[ryran]

The direct answer to your question is no. There's currently no way to add lame header info to existing mp3s.
You might find love with some kind of gap-killer DSP, though there's nothing like that for Rockbox at the moment. I'd say what arrow suggested is your best bet, though it's not gonna be pretty.

[jaybeee]

Try processing the files through MP3packer (or here)

Report back what you find when using this please.

[pabouk]

MP3packer does not add the LAME gapless tags but it can help some gapless players by adding correct VBR headers.

[lowlight]

In foobar2000, I think you can use the Utils > "Edit MP3 Gapless Playback Information" option to add encoder padding/delay info for non-lame files. I've never tried it.

[afruff23]

lowlight, I've seen that, but I have no idea what values to use.

[lowlight]

There are some guides in the foobar forums. Encoder delay is a fixed value that depends on the encoder used and then you experiment with the number of samples, counting down from the actual number, until the result is gapless. It's clearly it's not an efficient way to process a large number of mp3s.

[jaybeee]

MP3packer does not add the LAME gapless tags but it can help some gapless players by adding correct VBR headers.

Yes you're right. My bad.

And about the foobar util: yep, that could work, but as already said it isn't elegant. And what surprises me is that no-one has created a little tool to do such a thing. Tools like MrQuestionMan can tell what encoder was used, and so if they can do that, then they can add the gapless data surely. Maybe something for someone to think about.

[saratoga]

Tools like MrQuestionMan can tell what encoder was used, and so if they can do that, then they can add the gapless data surely. Maybe something for someone to think about.

Its not possible.  The encoder delay isn't enough, otherwise gapless information wouldn't even be needed.  You have to know how many samples were in the original file before it was encoded.  

[jaybeee]

Its not possible.  The encoder delay isn't enough, otherwise gapless information wouldn't even be needed.  You have to know how many samples were in the original file before it was encoded.  

That'll do it then  

Hadn't look into enough to figure out all the gapless stuff as I've always used LAME & foobar so get no probs. And with Rockbox it's grand too