With APS5_DUMP_FRAMES, FrameDumpWriter::Enqueue threw "frame dump queue exceeded 64 MiB" when the
writer thread fell more than 64 MiB behind, which failed the presentation and ended the title.
#4320 made that rare at the default APS5_DUMP_SCALE=4; at APS5_DUMP_SCALE=1 a 1920x1080 title
reaches it within nine frames and a 3840x2160 one on the third.
Enqueue now waits on the writer's condition variable until the frame fits, and the writer
notifies after each file; a single frame larger than the queue still throws. The VideoOut frame
dump queue test gets a wait mode at scale 1 whose third frame has to wait for the held first one.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
A frame presented from guest memory with APS5_DUMP_FRAMES is read back
at the size of the display buffer, and that whole copy went into the
dump writer's queue with the scale beside it (31.6 MiB for a 3840x2160
buffer). The queue holds 64 MiB, so the third frame the writer had not
finished ended the run with "frame dump queue exceeded 64 MiB". A frame
blitted from the resident image is already reduced on the GPU and queued
at the reduced size.
The readback is now reduced by the dump scale when the slot retires and
queued at that size, the same pixels the writer kept before. With
APS5_DUMP_SCALE=1 nothing is reduced and the limit is reached as before.
video_out_frame_dump_queue presents four 3840x2160 frames from guest
memory while the writer is held on the first file and compares every
dump with the decoded display buffer.
