diff options
Diffstat (limited to 'src/internal/subtitle/renderers/kitsubass.c')
| -rw-r--r-- | src/internal/subtitle/renderers/kitsubass.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/src/internal/subtitle/renderers/kitsubass.c b/src/internal/subtitle/renderers/kitsubass.c new file mode 100644 index 0000000..d0c5a80 --- /dev/null +++ b/src/internal/subtitle/renderers/kitsubass.c @@ -0,0 +1,188 @@ +#include <assert.h>
+#include <stdlib.h>
+
+#include <ass/ass.h>
+#include <SDL2/SDL_Surface.h>
+
+#include "kitchensink/kiterror.h"
+#include "kitchensink/internal/kitlibstate.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) {
+ 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 an, ao, x, y, x_off;
+ dst += img->dst_y * surface->pitch;
+
+ for(y = 0; y < img->h; y++) {
+ for(x = 0; x < img->w; x++) {
+ x_off = (img->dst_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 int ren_render_ass_cb(Kit_SubtitleRenderer *ren, void *src, double start_pts, void *dst) {
+ assert(ren != NULL);
+ assert(src != NULL);
+ assert(dst != NULL);
+
+ Kit_ASSSubtitleRenderer *ass_ren = ren->userdata;
+ AVSubtitle *sub = src;
+ SDL_Surface *surface = dst;
+ unsigned int now = start_pts * 1000;
+ int change = 0;
+
+ // 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.
+ ASS_Image *image = ass_render_frame(ass_ren->renderer, ass_ren->track, now, &change);
+ if(change <= 0) {
+ return -1;
+ }
+
+ for(; image; image = image->next) {
+ if(image->w == 0 || image->h == 0)
+ continue;
+ _ProcessAssImage(surface, image);
+ }
+
+ // We tell subtitle handler to clear output before adding this frame.
+ return 0;
+}
+
+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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