Issue when having a bunch of wave files

[TheBlueGamer-Github]

After I fixed my previous error, I found out I now have 2 new ones. 1. The final music that is included uses the 1st included DAC sample (I think it's the same reason as the 2nd error) 2. the 2nd-to-last song now corrupts after 6 seconds. Is there something I'm doing wrong?

SONIC.THE.HEDGEHOG.-.BlastEm.-.59.4.fps.2025-07-13.20-58-51.mp4

[vladikcomper]

What's the size of your ROM? Do you have SRAM enabled?

• If your ROM is larger than 4 MB, which is highly likely with a ton of long music on high sample rates, most of the emulators (Blastem included) will just cut off its data after 4 MB.
• If you have SRAM access constantly enabled, it's even worse, as SRAM replaces address space after 2nd MB of your ROM, so have to toggle SRAM access on/off, so ROM is accessible whenever you don't read/write SRAM.

[TheBlueGamer-Github]

I don’t have SRAM Enabled, and the ROM is 10 MB large.

[vladikcomper]

Well, there's your answer. Unfortunately, your ROM shouldn't exceed 4 MB for it to work under most emulators/hardware. There is some fork of Gens with 10 MB ROM support and IIRC someone made Kega Fusion fork as well, but I don't recommend going this way. On real hardware, you also can technically use up to 8 MB ROMs if cart board is designed this way, but this won't work with Mega CD addon attached.

The easier way is to probably reduce WAVE files sample rate, or compress some of them to DPCM, which makes data two times smaller. I described DPCM conversion here: https://github.com/vladikcomper/MegaPCM/blob/2.x/docs/Migration_from_MegaPCM_1.x.md#converting-dpcm-to-pcm

Mega PCM 2.1 will also introduce DPCM-HQ format (so wait for its release), which should improve sound quality on higher sample rates, while retaining the same compression ratio.

P.S.: Forgot to mention, Mega PCM's bankswitching can only support up to 8 MB ROMs (even larger than the "official" max ROM size of 4 MB"), but again, this won't work unless hardware and emulator support large ROMs specifically and there's nothing I can do about it.