mpv/sub/draw_bmp.h

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#ifndef MPLAYER_DRAW_BMP_H
#define MPLAYER_DRAW_BMP_H
#include "osd.h"
struct mp_image;
struct mp_draw_sub_cache;
draw_bmp: rewrite draw_bmp.c is the software blender for subtitles and OSD. It's used by encoding mode (burning subtitles), and some VOs, like vo_drm, vo_x11, vo_xv, and possibly more. This changes the algorithm from upsampling the video to 4:4:4 and then blending to downsampling the OSD and then blending directly to video. This has far-reaching consequences for its internals, and results in an effective rewrite. Since I wanted to avoid un-premultiplying, all blending is done with premultiplied alpha. That's actually the sane thing to do. The old code just didn't do it, because it's very weird in YUV fixed point. Essentially, you'd have to compensate for the chroma centering constant by subtracting src_alpha/255*128. This seemed so hairy (especially with correct rounding and high bit depths involved) that I went for using float. I think it turned out mostly OK, although it's more complex and less maintainable than before. reinit() is certainly a bit too long. While it should be possible to optimize the RGB path more (for example by blending directly instead of doing the stupid float conversion), this is probably slower. vo_xv users probably lose in this, because it takes the slowest path (due to subsampling requirements and using YUV). Why this rewrite? Nobody knows. I simply forgot the reason. But you'll have it anyway. Whether or not this would have required a full rewrite, at least it supports target alpha now (you can for example hard sub transparent PNGs, if you ever wanted to use mpv for this). Remove the check in vf_sub. The new draw_bmp.c is not as reliant on libswscale anymore (mostly uses repack.c now), and osd.c shows an error message on missing support instead now. Formats with chroma subsampling of 4 are not supported, because FFmpeg doesn't provide pixfmt definitions for alpha variants. We could provide those ourselves (relatively trivial), but why bother.
2020-05-09 16:01:07 +00:00
bool mp_draw_sub_bitmaps(struct mp_draw_sub_cache **cache, struct mp_image *dst,
video: make OSD/subtitle bitmaps refcounted (sort of) Making OSD/subtitle bitmaps refcounted was planend a longer time ago, e.g. the sub_bitmaps.packed field (which refcounts the subtitle bitmap data) was added in 2016. But nothing benefited much from it, because struct sub_bitmaps was usually stack allocated, and there was this weird callback stuff through osd_draw(). Make it possible to get actually refcounted subtitle bitmaps on the OSD API level. For this, we just copy all subtitle data other than the bitmaps with sub_bitmaps_copy(). At first, I had planned some fancy refcount shit, but when that was a big mess and hard to debug and just boiled to emulating malloc(), I made it a full allocation+copy. This affects mostly the parts array. With crazy ASS subtitles, this parts array can get pretty big (thousands of elements or more), in which case the extra alloc/copy could become performance relevant. But then again this is just pure bullshit, and I see no need to care. In practice, this extra work most likely gets drowned out by libass murdering a single core (while mpv is waiting for it) anyway. So fuck it. I just wanted this so draw_bmp.c requires only a single call to render everything. VOs also can benefit from this, because the weird callback shit isn't necessary anymore (simpler code), but I haven't done anything about it yet. In general I'd hope this will work towards simplifying the OSD layer, which is prerequisite for making actual further improvements. I haven't tested some cases such as the "overlay-add" command. Maybe it crashes now? Who knows, who cares. In addition, it might be worthwhile to reduce the code duplication between all the things that output subtitle bitmaps (with repacking, image allocation, etc.), but that's orthogonal.
2020-04-26 21:34:32 +00:00
struct sub_bitmap_list *sbs_list);
draw_bmp: rewrite draw_bmp.c is the software blender for subtitles and OSD. It's used by encoding mode (burning subtitles), and some VOs, like vo_drm, vo_x11, vo_xv, and possibly more. This changes the algorithm from upsampling the video to 4:4:4 and then blending to downsampling the OSD and then blending directly to video. This has far-reaching consequences for its internals, and results in an effective rewrite. Since I wanted to avoid un-premultiplying, all blending is done with premultiplied alpha. That's actually the sane thing to do. The old code just didn't do it, because it's very weird in YUV fixed point. Essentially, you'd have to compensate for the chroma centering constant by subtracting src_alpha/255*128. This seemed so hairy (especially with correct rounding and high bit depths involved) that I went for using float. I think it turned out mostly OK, although it's more complex and less maintainable than before. reinit() is certainly a bit too long. While it should be possible to optimize the RGB path more (for example by blending directly instead of doing the stupid float conversion), this is probably slower. vo_xv users probably lose in this, because it takes the slowest path (due to subsampling requirements and using YUV). Why this rewrite? Nobody knows. I simply forgot the reason. But you'll have it anyway. Whether or not this would have required a full rewrite, at least it supports target alpha now (you can for example hard sub transparent PNGs, if you ever wanted to use mpv for this). Remove the check in vf_sub. The new draw_bmp.c is not as reliant on libswscale anymore (mostly uses repack.c now), and osd.c shows an error message on missing support instead now. Formats with chroma subsampling of 4 are not supported, because FFmpeg doesn't provide pixfmt definitions for alpha variants. We could provide those ourselves (relatively trivial), but why bother.
2020-05-09 16:01:07 +00:00
char *mp_draw_sub_get_dbg_info(struct mp_draw_sub_cache *c);
extern const bool mp_draw_sub_formats[SUBBITMAP_COUNT];
#endif /* MPLAYER_DRAW_BMP_H */
// vim: ts=4 sw=4 et tw=80