Movie players like the one in Star Wars: Lethal Alliance present every decoded
frame after a single vblank wait, with no clock or timestamp check, so the
frame rate depends on decode, CSC, ATRAC decode and the GE blit adding up to
more than a vblank. We charged nearly nothing for any of them, so such movies
ran at 60 fps until the ringbuffer's slack ran out.
Costs measured on a PSP with a copy of that player (pspautotests
video/mpeg/playertiming), for a 480x272 frame:
- sceVideocodecDecode: 3.4ms (sceMpegAvcDecode 5.8ms less sceMpegAvcCsc 2.4ms)
- sceMpegBaseCscAvc: 2.4ms, was a flat 4ms
- sceAudiocodecDecode, ATRAC3+ only: 2.5ms per frame
- GE: 9.7ms for a through-mode rectangle blit from a decoded video frame,
charged by area, only for textures in the buffer a decoder last wrote.
GE time also now carries across stall address updates. Before, a list sent
in stalled chunks only had its last chunk's time counted, so sceGeDrawSync
returned 39us after a blit that takes 9.7ms. This affects every game that
builds its lists incrementally, so GE-timing-sensitive games need checking.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
