static int encode_dvd_subtitles(uint8_t *outbuf, int outbuf_size, const AVSubtitle *h) { uint8_t *q, *qq; int object_id; int offset1[20], offset2[20]; int i, imax, color, alpha, rects = h->num_rects; unsigned long hmax; unsigned long hist[256]; int cmap[256]; if (rects == 0 || h->rects == NULL) return -1; if (rects > 20) rects = 20; // analyze bitmaps, compress to 4 colors for (i=0; i<256; ++i) { hist[i] = 0; cmap[i] = 0; } for (object_id = 0; object_id < rects; object_id++) for (i=0; i<h->rects[object_id]->w*h->rects[object_id]->h; ++i) { color = h->rects[object_id]->pict.data[0][i]; // only count non-transparent pixels alpha = ((uint32_t*)h->rects[object_id]->pict.data[1])[color] >> 24; hist[color] += alpha; } for (color=3;; --color) { hmax = 0; imax = 0; for (i=0; i<256; ++i) if (hist[i] > hmax) { imax = i; hmax = hist[i]; } if (hmax == 0) break; if (color == 0) color = 3; av_log(NULL, AV_LOG_DEBUG, "dvd_subtitle hist[%d]=%ld -> col %d\n", imax, hist[imax], color); cmap[imax] = color; hist[imax] = 0; } // encode data block q = outbuf + 4; for (object_id = 0; object_id < rects; object_id++) { offset1[object_id] = q - outbuf; // worst case memory requirement: 1 nibble per pixel.. if ((q - outbuf) + h->rects[object_id]->w*h->rects[object_id]->h/2 + 17*rects + 21 > outbuf_size) { av_log(NULL, AV_LOG_ERROR, "dvd_subtitle too big\n"); return -1; } dvd_encode_rle(&q, h->rects[object_id]->pict.data[0], h->rects[object_id]->w*2, h->rects[object_id]->w, h->rects[object_id]->h >> 1, cmap); offset2[object_id] = q - outbuf; dvd_encode_rle(&q, h->rects[object_id]->pict.data[0] + h->rects[object_id]->w, h->rects[object_id]->w*2, h->rects[object_id]->w, h->rects[object_id]->h >> 1, cmap); } // set data packet size qq = outbuf + 2; bytestream_put_be16(&qq, q - outbuf); // send start display command bytestream_put_be16(&q, (h->start_display_time*90) >> 10); bytestream_put_be16(&q, (q - outbuf) /*- 2 */ + 8 + 12*rects + 2); *q++ = 0x03; // palette - 4 nibbles *q++ = 0x03; *q++ = 0x7f; *q++ = 0x04; // alpha - 4 nibbles *q++ = 0xf0; *q++ = 0x00; //*q++ = 0x0f; *q++ = 0xff; // XXX not sure if more than one rect can really be encoded.. // 12 bytes per rect for (object_id = 0; object_id < rects; object_id++) { int x2 = h->rects[object_id]->x + h->rects[object_id]->w - 1; int y2 = h->rects[object_id]->y + h->rects[object_id]->h - 1; *q++ = 0x05; // x1 x2 -> 6 nibbles *q++ = h->rects[object_id]->x >> 4; *q++ = (h->rects[object_id]->x << 4) | ((x2 >> 8) & 0xf); *q++ = x2; // y1 y2 -> 6 nibbles *q++ = h->rects[object_id]->y >> 4; *q++ = (h->rects[object_id]->y << 4) | ((y2 >> 8) & 0xf); *q++ = y2; *q++ = 0x06; // offset1, offset2 bytestream_put_be16(&q, offset1[object_id]); bytestream_put_be16(&q, offset2[object_id]); } *q++ = 0x01; // start command *q++ = 0xff; // terminating command // send stop display command last bytestream_put_be16(&q, (h->end_display_time*90) >> 10); bytestream_put_be16(&q, (q - outbuf) - 2 /*+ 4*/); *q++ = 0x02; // set end *q++ = 0xff; // terminating command qq = outbuf; bytestream_put_be16(&qq, q - outbuf); av_log(NULL, AV_LOG_DEBUG, "subtitle_packet size=%td\n", q - outbuf); return q - outbuf; }