Option To Play Song Tracks Backwards

[redblade8]

Hiya, a feature that I thought would be good to share would be the ability to play songs backwards. You could toggle it with on, or off.
This is a feature that I miss from windows 95/98 in the sound recorder that was called 'reverse'.

Thanks for reading! ~Red.

[saratoga]

This isn't really possible with anything but WAV and maybe a few other formats, so its not going to happen.

[redblade8]

This isn't really possible with anything but WAV and maybe a few other formats, so its not going to happen.

Well, I wasn't asking if it would happen or not, so I'm guessing what you're actually saying is that it's just not possible with all formats currently.

What formats would be supported? Wav you said was one of them. Is it too CPU intensive to work on all target devices? For a 80mhz CPU? Edit: The minimum requirements for Windows 95/98 are less than the technical specifications of the sansa e200 series. Which is for an entire OS, and not just one function only, so I'm sure that this could run without problems. Apparently Windows 3.1 had this as well.

I'm not sure if the 'reverse' function on Windows 95/98 only worked for .wav files, or if it worked on .mp3 as well.

How come it's not possible to do this with all music formats? Mp3 is not possible because of which?

Thanks for your reply! It's much appreciated =)

[natanelho]

anything can be done. the question is how much work would it take, and will it lag.
doing reverse with WAV is really simple, however MP3 needs more work to be done by the proccessor before you get the reverse track, and its not as easy as with WAV.

if you want it, just make a plugin/script for it.

[saratoga]

It's possible on wav since it's an uncompressed format. With compression proceeding samples typically are needed to decode the previous one.

Regardless this isn't something we would support in rockbox, so you should just reverse the tracks on your PC.

[redblade8]

Oh. I don't have the luxury of reversing the tracks on my PC, so using rockbox would be key, regardless of there being people who support it, and people who don't support it, as it's just not possible for me. But then again , as you said , there would need to be a general agreement and support if it were to be implemented, though I wasn't asking for it to be implemented. It was just an idea I thought Id throw out there to discuss.

There's also the issue of having multiple tracks, one reversed, one not reversed, taking up space on your mp3 player, which I wouldn't have the room for. It's just meant to be a feature you can turn on or off, and not an actual permanent song track.

So the idea would work much better on rockbox, but would be more practical on the PC since it can handle these things better. But also, more practical use can be had on rockbox as a feature , as you wouldn't have multiple tracks eating up space on your mp3 player.

I'm guessing that this is decoding a song track to make it backwards, thus taking up many more cpu and ram resources than say just encoding an mp3 track, which is already implemented in rockbox.

Perhaps there could be another solution as well. A program on the PC, that would decode your mp3 tracks , and create some sort of .rvs file to be read by rockbox. This file would then tell rockbox how to reverse the file, but wouldn't actually be the entire track. I'm not sure if this would be pointless though, as the resulting file could be larger than the original file? Though I'd say it might be alot less.

I'm guessing this wouldn't be done for the same reason that decoding and converting video files to .MPEG on rockbox isn't done yet. Even if this would make more sense to do on rockbox than converting videos , as this is just a song option, like how pitch is just a song feature on rockbox too.

Though this isn't just like pitch, it's also decoding a compressed track to allow it to play backwards. Even if it's the same idea of modifying the sound of a track, it's decoding, plus modifying the sound of a song at the same time, whilst pitch doesn't do any decoding, it just modifies the sound of the song track.

[saratoga]

I think probably the best you could do would be a plugin that decoded the file to disk, reversed it, and then let you play the reversed .wav file.  If you want to work on that, I think it would be doable. 

[redblade8]

I think probably the best you could do would be a plugin that decoded the file to disk, reversed it, and then let you play the reversed .wav file.  If you want to work on that, I think it would be doable.

Yes, that's true thanks. I was just reading your answer somewhere else : "For effects on things like decoded audio or live recorded audio, a plugin might be the best place to start:"

I just have one question now though, can a plugin be integrated into a menu so that it's not just a separate plugin only? Like if you held the middle button on the sansa e200's while playing a song, you could then go to sound , then pitch ( I don't have a player on me currently to verify the procedure of doing this. )

Like let's say the option pitch called for the plugin, pitch.rock, ( I forget if .rock is only for games, this is just an example..)

Then pitch could be on the same menu as the rest of the sound options like eq, and everything,  just that it is actually a plugin that does the work of changing the pitch and tempo of a song that is being called on, but in a main menu.

[saratoga]

I don't think you can do something like that with plugins.  Plus for reversing audio you probably wouldn't want to anyway.  You'd probably want the plugin to have its own user interface.   

[redblade8]

Oh, thanks. That's too bad that you couldn't do that though, Id much rather all my sound options like pitch and everything to be on the same menu. I wouldn't want just a separate plugin. I'm not sure what kind of interface I'd want though. I would just want an on and off option which is a less complicated & simple interface  than pitch currently has. 

Thanks for telling me that it is not possible. It was just an idea anyhows.