Add libplacebo GPU module with render and shader filters#1236
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ddennedy wants to merge 13 commits intorefactor-image-convertfrom
Open
Add libplacebo GPU module with render and shader filters#1236ddennedy wants to merge 13 commits intorefactor-image-convertfrom
ddennedy wants to merge 13 commits intorefactor-image-convertfrom
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New module 'placebo' providing GPU-accelerated video processing via libplacebo. Includes two filters: - placebo.render: GPU scaling, debanding, dithering, and tonemapping with quality presets (fast/default/high_quality) - placebo.shader: Custom mpv-compatible .hook shader support Backend priority: D3D11 (Windows) -> Vulkan -> OpenGL. Vulkan loader is dynamically loaded on Windows when libplacebo is built without vk-proc-addr support. Features: - Singleton GPU context with thread-safe access - Shader cache persistence - Multiple scaling algorithms (ewa_lanczos, lanczos, mitchell, etc.) - Tone mapping (auto, clip, mobius, reinhard, hable, bt.2390, spline) - Graceful fallback to passthrough when no GPU is available The module is enabled by default but skipped automatically when libplacebo is not installed.
Use PRIu64/PRId64 from <inttypes.h> instead of %zu/%ld for size logging in the placebo module. Add libplacebo-dev packages to Ubuntu, Debian, and Fedora 42 CI workflows, and mingw-w64-x86_64-libplacebo to the MSYS2 MinGW64 workflow.
Break long mlt_log_info() call into multi-line format to match the project's clang-format rules (same style as load_cache above).
When multiple placebo filters are stacked on one clip, each filter previously did a full RAM→GPU upload and GPU→RAM download. The intermediate uploads are redundant because the next placebo filter would re-upload the same pixels immediately. Each filter now attaches its output texture to the mlt_frame via placebo_frame_put_tex(). The next placebo filter calls placebo_frame_take_tex() to grab it directly as source, skipping the upload. The download to RAM still happens every time (MLT expects the image buffer to be current for non-GPU filters). Staleness detection: put_tex records the RAM buffer pointer, take_tex compares it against the current pointer. If a CPU filter ran in between and requested a writable buffer (triggering a copy and new allocation), the pointers differ and take_tex returns NULL, falling back to a fresh upload. Also cleans up internal ticket-style comments (C1/W2/etc.) with descriptions of actual logic and pitfalls.
Add apply_shader_params() to override pl_hook DYNAMIC parameters from
MLT animated properties (shader_param.* prefix) on every frame. Uses
mlt_properties_anim_get_double/int to correctly resolve keyframe strings
("0=200;50=100") at the current frame position.
Add base64 decoding for shader_text values prefixed with "base64:" to
support inline shaders with characters that are problematic in MLT
property strings.
Run clang-format-14 (matching CI) on filter_placebo_shader.c and gpu_context.c to fix designated initializer spacing, ternary line breaks, and long argument lists.
…into libplacebo
- Introduced new `mlt_image_private` format for module internal use. - Improved placebo texture reuse across filters.
ddennedy
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supersedes #1201