A monitor whose source signals full range (Dahua h264) decodes to
AV_PIX_FMT_YUVJ420P, and Monitor passes that format through to shared memory
unchanged. When zms scales such a frame for montage or console thumbnails,
SWScale::Convert mapped only the input format through fix_deprecated_pix_fmt()
and handed the still-deprecated YUVJ format to swscale as the destination, so
libswscale logged
deprecated pixel format used, make sure you did set range correctly
for every context it built. Watch view at 100% scale never hit it because
Image::Scale returns early when the dimensions already match.
Map deprecated formats on both sides in SWScale::Convert (both the buffer and
the AVFrame overload), in Image::Assign(AVFrame*), in
Monitor::setupConvertContext and in the LocalCamera conversion context.
Mapping the destination YUVJ format to its non-J equivalent makes swscale
default that side to limited range, which would compress full-range output.
Replace zm_sws_set_input_range() with zm_sws_set_ranges(), which takes the
original pre-fix formats for both sides and sets srcRange/dstRange accordingly.
Image::Assign(AVFrame*) now compares the mapped source and destination formats,
so a YUVJ420P frame into a YUVJ420P image takes the av_image_copy fast path
instead of running through swscale.
Image::Scale built a fresh SWScale, and therefore a fresh sws context, on every
call. That is a full sws_init_context per scaled frame per stream, and it is
what turned the warning into a per-frame flood rather than a one-off. Reuse a
thread_local SWScale; sws_getCachedContext re-inits itself when the geometry
changes.
Tests: zm_swscale_range.cpp installs an av_log callback and asserts that
SWScale::Convert with a YUVJ destination and Image::Scale on a YUVJ420P image
emit no deprecated-format message, plus a luma check that the range handling
still survives the mapping.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NDhTBPj9xEaT52pRmAufaP
swscale assumes limited (MPEG, 16-235) input range by default. Mapping a
full-range JPEG format (YUVJ*) to its non-J equivalent for the conversion
therefore washes the colours out, because full-range luma/chroma gets
treated as limited.
Add pix_fmt_is_jpeg_range() and zm_sws_set_input_range(), which sets
srcRange=1 on the context when the original source format was full range.
Apply it at every conversion site that takes decoded frames: Image::Assign
and both SWScale::Convert overloads. Monitor::setupConvertContext already
did this inline with a hand-rolled switch and colorspace block; replace
that with the shared helpers to remove the duplication.
Add tests/zm_swscale_range.cpp: converting a Y=16 YUVJ420P image to RGB24
keeps luma ~16 (full range) rather than being crushed to ~0 (limited).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
