[REPO Man]

If Sonic CD's music is stored as redbook audio, could one, in theory, swap out the tracks with new ones? If so, what would the rules be? Does it have to be the same length as the original song? What bitrate does it need to be?

[nineko]

If you're using an emulator, and you're using an iso/mp3 rip, you just need to replace the mp3s with other ones.

[GerbilSoft]

If Sonic CD's music is stored as redbook audio, could one, in theory, swap out the tracks with new ones? If so, what would the rules be?

Yes. No specific rules, but the replacement tracks have to match the ordering of the originals. (e.g. Palmtree Panic 1 'P' Mix is Track 3, 'G' mix is Track 4, etc.)

Does it have to be the same length as the original song?

No, except for the title screen. (The title screen is hard-coded to fade to demo after a certain duration.)

What bitrate does it need to be?

Standard CD-DA: 44.1 kHz, signed 16-bit BE stereo PCM. (1411 Kbps)

This post has been edited by GerbilSoft: 02 February 2011 - 12:03 AM

[Andlabs]

The only songs you cannot replace without hacking are the past songs (which are stored as programs that send samples to a special PCM chip much like how a tracker plays back modules). I should have the past song format documented by next week or something (sooner if I didn't want to release sample rips simultaneously).

I have no idea how the sound in the PC port(s?) works.

In general the rule for Sega CD games is: does the game store its audio has regular music tracks? If so, you should be able to replace them by just using different tracks. Conversely, stick your disc in a CD player and skip track 1 to hear the soundtrack.

This post has been edited by Andlabs: 02 February 2011 - 02:20 AM

[MainMemory]

I have no idea how the sound in the PC port(s?) works.

PC version uses only CD audio. Gems Collection uses ADX.

[REPO Man]

The only songs you cannot replace without hacking are the past songs (which are stored as programs that send samples to a special PCM chip much like how a tracker plays back modules). I should have the past song format documented by next week or something (sooner if I didn't want to release sample rips simultaneously).

I have no idea how the sound in the PC port(s?) works.

In general the rule for Sega CD games is: does the game store its audio has regular music tracks? If so, you should be able to replace them by just using different tracks. Conversely, stick your disc in a CD player and skip track 1 to hear the soundtrack.

Sucks I can't change the past songs.

But... can this work with Redbook audio games for other consoles?

[dsrb]

Usually. It's fairly safe to ignore the words "Sega CD" in the final paragraph of the post you quoted.

[Mr Lange]

Wow so that's why only the past level music plays for me. >.>
I'm interested in the idea that all the music could be replaced with tracker formats. That sounds like fun.

[REPO Man]

One idea is to replace all of the Bad Future tracks with Marilyn Manson ones, Good Future with something more upbeat, and the Present with their Japanese counterparts.

Another dumbshit question (from a dumbshit of the hacking world)... can the boss music be changed, cuz I'm thinking "Behold the Machine" by steampunk/darkwave band Vernian Process.

[Andlabs]

The boss music is a normal CD track, yes.

Also I think the US version (not sure about the others) plays Stardust Speedway Bad Future for the Metal Sonic race no matter what (you get the appropriate music beforehand), so choose wisely =P

This post has been edited by Andlabs: 03 February 2011 - 01:31 AM

[dsrb]

Wow so that's why only the past level music plays for me. >.>

What system are you running the game on? I'm now wondering if I'm remembering correctly that there was a PC edition whose manufacturers somehow omitted to include the Redbook audio tracks, as with Rayman Gold. If I'm not totally wrong, I had a copy of it from a friend.

[GeneHF]

It's also recommended you use a CUE sheet for best results, since sometimes, some MP3s may not behave properly in an emulator.

Example of some sound editing I did:




It's really not that hard, but it pays off really well if you use music that fits the stages thematically.

[ValleyBell]

It's also recommended you use a CUE sheet for best results, since sometimes, some MP3s may not behave properly in an emulator.

As long as your mp3s have a constant bitrate, it's all fine. Windows fails to calculate the correct length of VBR mp3s and emulators like Gens behave strange because of that.

[GerbilSoft]

It's also recommended you use a CUE sheet for best results, since sometimes, some MP3s may not behave properly in an emulator.

As long as your mp3s have a constant bitrate, it's all fine. Windows fails to calculate the correct length of VBR mp3s and emulators like Gens behave strange because of that.

Gens doesn't use Windows' MP3 decoder; it uses an ancient copy of mpg123, which has caused a multitude of problems before with Gens/GS. (The first time I tried building Gens/GS on Win32, it crashed because of some weird issue with mpg123.)

I'd recommend using either ISO/WAV or BIN/CUE if you're experimenting with audio placement, since then you don't have to deal with MP3 bitrate oddities. (Kega supports BIN/CUE and I think it also supports ISO/WAV. Gens unfortunately only supports ISO/MP3 at the moment.)