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#include <assert.h>
#include <stdlib.h>
#include <ass/ass.h>
#include <SDL2/SDL_Surface.h>
#include "kitchensink/kiterror.h"
#include "kitchensink/internal/utils/kitlog.h"
#include "kitchensink/internal/kitlibstate.h"
#include "kitchensink/internal/subtitle/kitsubtitlepacket.h"
#include "kitchensink/internal/utils/kithelpers.h"
#include "kitchensink/internal/subtitle/renderers/kitsubass.h"
// For compatibility
#ifndef ASS_FONTPROVIDER_AUTODETECT
#define ASS_FONTPROVIDER_AUTODETECT 1
#endif
typedef struct Kit_ASSSubtitleRenderer {
ASS_Renderer *renderer;
ASS_Track *track;
} Kit_ASSSubtitleRenderer;
static void _ProcessAssImage(SDL_Surface *surface, const ASS_Image *img, int min_x, int min_y) {
unsigned char r = ((img->color) >> 24) & 0xFF;
unsigned char g = ((img->color) >> 16) & 0xFF;
unsigned char b = ((img->color) >> 8) & 0xFF;
unsigned char a = (img->color) & 0xFF;
unsigned char *src = img->bitmap;
unsigned char *dst = surface->pixels;
unsigned int pos_x = img->dst_x - min_x;
unsigned int pos_y = img->dst_y - min_y;
unsigned int an, ao, x, y, x_off;
dst += pos_y * surface->pitch;
for(y = 0; y < img->h; y++) {
for(x = 0; x < img->w; x++) {
x_off = (pos_x + x) * 4;
an = ((255 - a) * src[x]) >> 8; // New alpha
ao = dst[x_off + 3]; // Original alpha
if(ao == 0) {
dst[x_off + 0] = r;
dst[x_off + 1] = g;
dst[x_off + 2] = b;
dst[x_off + 3] = an;
} else {
dst[x_off + 3] = 255 - (255 - dst[x_off + 3]) * (255 - an) / 255;
if(dst[x_off + 3] != 0) {
dst[x_off + 0] = (dst[x_off + 0] * ao * (255-an) / 255 + r * an ) / dst[x_off + 3];
dst[x_off + 1] = (dst[x_off + 1] * ao * (255-an) / 255 + g * an ) / dst[x_off + 3];
dst[x_off + 2] = (dst[x_off + 2] * ao * (255-an) / 255 + b * an ) / dst[x_off + 3];
}
}
}
src += img->stride;
dst += surface->pitch;
}
}
static Kit_SubtitlePacket* ren_render_ass_cb(Kit_SubtitleRenderer *ren, void *src, double start_pts, double end_pts) {
assert(ren != NULL);
assert(src != NULL);
Kit_ASSSubtitleRenderer *ass_ren = ren->userdata;
AVSubtitle *sub = src;
SDL_Surface *surface = NULL;
ASS_Image *image = NULL;
ASS_Image *wt_image = NULL;
unsigned int now = start_pts * 1000;
int change = 0;
int x0 = INT_MAX, y0 = INT_MAX;
int x1 = 0, y1 = 0;
int w, h;
// Read incoming subtitle packets to libASS
for(int r = 0; r < sub->num_rects; r++) {
if(sub->rects[r]->ass == NULL)
continue;
ass_process_data(ass_ren->track, sub->rects[r]->ass, strlen(sub->rects[r]->ass));
}
// Ask libass to render frames. If there are no changes since last render, stop here.
wt_image = image = ass_render_frame(ass_ren->renderer, ass_ren->track, now, &change);
if(change == 0) {
return NULL;
}
// Find dimensions
for(image = wt_image; image; image = image->next) {
if(image->dst_x < x0)
x0 = image->dst_x;
if(image->dst_y < y0)
y0 = image->dst_y;
if(image->dst_x + image->w > x1)
x1 = image->dst_x + image->w;
if(image->dst_y + image->h > y1)
y1 = image->dst_y + image->h;
}
w = x1 - x0;
h = y1 - y0;
// Surface to render on
surface = SDL_CreateRGBSurfaceWithFormat(0, w, h, 32, SDL_PIXELFORMAT_RGBA32);
SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);
SDL_FillRect(surface, NULL, 0);
// Render subimages to the target surface.
for(image = wt_image; image; image = image->next) {
if(image->w == 0 || image->h == 0)
continue;
_ProcessAssImage(surface, image, x0, y0);
}
// We tell subtitle handler to clear output before adding this frame.
return Kit_CreateSubtitlePacket(start_pts, end_pts, x0, y0, surface);
}
static void ren_close_ass_cb(Kit_SubtitleRenderer *ren) {
if(ren == NULL) return;
Kit_ASSSubtitleRenderer *ass_ren = ren->userdata;
ass_renderer_done(ass_ren->renderer);
free(ass_ren);
}
Kit_SubtitleRenderer* Kit_CreateASSSubtitleRenderer(const Kit_Decoder *dec, int w, int h) {
assert(dec != NULL);
assert(w >= 0);
assert(h >= 0);
// Make sure that libass library has been initialized + get handle
Kit_LibraryState *state = Kit_GetLibraryState();
if(state->libass_handle == NULL) {
Kit_SetError("Libass library has not been initialized");
return NULL;
}
// First allocate the generic decoder component
Kit_SubtitleRenderer *ren = Kit_CreateSubtitleRenderer();
if(ren == NULL) {
goto exit_0;
}
// Next, allocate ASS subtitle renderer context.
Kit_ASSSubtitleRenderer *ass_ren = calloc(1, sizeof(Kit_ASSSubtitleRenderer));
if(ass_ren == NULL) {
goto exit_1;
}
// Initialize libass renderer
ASS_Renderer *ass_renderer = ass_renderer_init(state->libass_handle);
if(ass_renderer == NULL) {
Kit_SetError("Unable to initialize libass renderer");
goto exit_2;
}
// Read fonts from attachment streams and give them to libass
for(int j = 0; j < dec->format_ctx->nb_streams; j++) {
AVStream *st = dec->format_ctx->streams[j];
if(st->codec->codec_type == AVMEDIA_TYPE_ATTACHMENT && attachment_is_font(st)) {
const AVDictionaryEntry *tag = av_dict_get(
st->metadata,
"filename",
NULL,
AV_DICT_MATCH_CASE);
if(tag) {
ass_add_font(
state->libass_handle,
tag->value,
(char*)st->codec->extradata,
st->codec->extradata_size);
}
}
}
// Init libass fonts and window frame size
ass_set_fonts(
ass_renderer,
NULL, "sans-serif",
ASS_FONTPROVIDER_AUTODETECT,
NULL, 1);
ass_set_frame_size(ass_renderer, w, h);
ass_set_hinting(ass_renderer, ASS_HINTING_NONE);
// Initialize libass track
ASS_Track *ass_track = ass_new_track(state->libass_handle);
if(ass_track == NULL) {
Kit_SetError("Unable to initialize libass track");
goto exit_3;
}
// Set up libass track headers (ffmpeg provides these)
if(dec->codec_ctx->subtitle_header) {
ass_process_codec_private(
ass_track,
(char*)dec->codec_ctx->subtitle_header,
dec->codec_ctx->subtitle_header_size);
}
// Set callbacks and userdata, and we're go
ass_ren->renderer = ass_renderer;
ass_ren->track = ass_track;
ren->ren_render = ren_render_ass_cb;
ren->ren_close = ren_close_ass_cb;
ren->userdata = ass_ren;
return ren;
exit_3:
ass_renderer_done(ass_renderer);
exit_2:
free(ass_ren);
exit_1:
Kit_CloseSubtitleRenderer(ren);
exit_0:
return NULL;
}
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