cache_pause=no caused frame-wait-frame-wait on uncached videos
because mpv kept playing through buffer underruns instead of
pausing to refill. Flip to cache_pause=yes with a 2s resume
threshold so playback is smooth after the initial buffer fill.
Also: bump demuxer buffers (50→150MiB forward, add 75MiB back for
backward seek without refetch), increase stream_buffer_size from
default 128KiB to 4MiB to reduce syscall overhead, extend network
timeout (10→30s) for slow CDNs, and set a browser-like user agent
to avoid 403s from boorus that block mpv's default UA.
behavior change
The previous attempt set ``demuxer_lavf_o`` as an init kwarg with a
comma-laden ``protocol_whitelist=file,http,https,tls,tcp`` value.
mpv rejected it with -7 OPT_FORMAT because python-mpv's init path
goes through ``mpv_set_option_string``, which routes through mpv's
keyvalue list parser — that parser splits on ``,`` to find entries,
shredding the protocol list into orphan tokens. Backslash-escaping
``\,`` did not unescape on this code path either.
Splits the option set into two helpers:
- ``build_mpv_kwargs`` — init kwargs only (ytdl=no, load_scripts=no,
POSIX input_conf null, all the existing playback/audio/network
tuning). The lavf option is intentionally absent.
- ``lavf_options`` — a dict applied post-construction via the
python-mpv property API, which uses the node API and accepts
dict values for keyvalue-list options without splitting on
commas inside the value.
Tests cover both paths: that ``demuxer_lavf_o`` is NOT in the init
kwargs (regression guard), and that ``lavf_options`` returns the
expected protocol set.
Audit-Ref: SECURITY_AUDIT.md finding #2
Severity: High
Extracts the mpv.MPV() kwargs into a Qt-free pure function so the
security-relevant options can be unit-tested on CI (which lacks
PySide6 and libmpv). The builder embeds the audit #2 hardening —
ytdl="no", load_scripts="no", and a lavf protocol whitelist of
file,http,https,tls,tcp — alongside the existing playback tuning.
Not yet wired into _MpvGLWidget; that lands in the next commit.
Audit-Ref: SECURITY_AUDIT.md finding #2
Severity: High
