Entry 245

The later openings, libmpeg's frame base, and a line of size 0

2026-09-27format

Filesdocs/formats/pss.mddocs/formats/voice.mdcrates/piney-mpeg/tests/ffmpeg.rscrates/piney-audio/src/seword.rs

Asked for: more of the docs' open questions. This entry covers the movie and voice pages. The questions left there need a console: the IPU's IDCT, the SPU2's timing, the disc's latency.

The movies

• The other volumes. The logos are the same bytes on all four discs.

  • OPENING2-4 are made as Infection's OPENING is. Only Mutation's has a higher bit rate (8.19 against 5.12 Mbit/s).

  • Every audio stream has the same SShd.

  • The players:

    • Mutation's is Infection's code;
    • Outbreak's and Quarantine's are that code built by another compiler.

    Compared function by function, they make the same calls with the same constants and field offsets.

  The new test later_openings_match_ffmpeg_exactly finds all 2,733, 2,630 and 2,715 pictures equal to ffmpeg's, byte for byte.

• frameCount's base. It is libmpeg's private +0xac. sceMpegCreate and Reset zero it. _markOutput sets it to the picture counter when the first reference picture is shown, which is during the second decode. So it is 1, and frameCount is the display index of the last picture out, as the page and the port (Movie::skippable) already had it.

• SShd.type is 1 in all four openings and read by nothing: moved to Notes.

The voice

• CCSTRM_PCM's type, bitNum, trackType. Decode_Pcm reads the structure onto its stack and uses only dataNum and dataSize.

• A read of a negative size. A line under 16 KiB asks for one at its first interrupt. The IOP's reply, read from IOPRP243.IMG's 2.4.3 modules:

  • SEWORDS's files are opened for stream reads, so the size reaches CDVDMAN's blocking stream read as size >> 11 sectors.
  • Its copy compares sizes unsigned, so it copies every buffered sector past the 8 KiB raw half and waits for more; the count never matches.
  • A normal read would have returned -22.

• Who asks. Every skill-word table, in both languages and on all four discs, ends with a {0, 0} row. skillVoicePlay only skips ofs == -1.

  • Kite reaches his with skill 295, Para Repth (base 123).
  • Para Repth is the Recovery Drink's skill (itemTblR 23).
  • Quarantine gives Kite five at a new game, and trades them.

  Quarantine's code along the way is the same. The port's seword::Word returns nothing for a read of 0 or fewer bytes, so there the line plays its 16 KiB preload and ends; its comment now says so.