Crate psx_fmv 

FMV playback building blocks for PS1 guests.

A movie is a .STR file: 2048-byte sectors, each carrying a 32-byte chunk header and 2016 bytes of one frame’s compressed bitstream (the “BS” format). Playing one is a pipeline:

1. CD sectors stream in (the caller owns the drive; see the hello-fmv example) and stream::FrameAssembler stitches a frame’s chunks back together.
2. bitstream::decode_frame runs the variable-length decode on the CPU, turning the bitstream into the MDEC’s run-length halfwords.
3. mdec::Mdec, the driver that owns the MDEC’s DMA channels, feeds those to the MDEC over DMA0 and pulls decoded 16-pixel-wide columns back over DMA1 for upload to VRAM.

Everything but mdec is plain logic, built and tested on the host; the driver only touches a register when one of its methods runs.

A game that only wants to play a movie calls player::play (guest only), which runs all three stages overlapped and shows the result; the hello-fmv example is the simpler, sector-checking test player.

Bitstream versions 1 and 2 (the same coding) are decoded; v3 differs in the DC coding and is rejected with bitstream::DecodeError::Version.

The encoder is psxavenc (zlib license), run as a host build tool: psxavenc -t strv -v v2 -s 320x240 -r 15 -x 2 in.mp4 out.str.

Modules

bitstream

BS (“bitstream”) frame decode: variable-length codes to MDEC run-length halfwords.

idct

The MDEC’s IDCT matrix, generated from the DCT basis.

iso

Minimal ISO9660 lookup: find a file in the disc’s root directory.

mdec

MDEC driver: table upload, decode command, DMA0 in, DMA1 out.

player

A streaming STR player a game can call: play streams one movie from the disc at double speed, decodes it through the MDEC and shows it, with its interleaved XA audio going straight from the drive to the SPU.

rle

Run-length data: what crate::bitstream::decode_frame produces and the MDEC decodes, and the lengths the MDEC can be handed.

stream

STR video sectors: the 32-byte chunk header and frame reassembly.