Danmaku2ass (C++ Version)

Features

Danmaku2ASS converts comments from Niconico/Acfun/Bilibili to ASS format so that you can play it with any media player supporting ASS subtitle.

Written in C++, it can convert 10,000 comments in just 0.05 seconds. It doesn't depend on any third-party libraries, so it is easy to embed.

This library is based on the works of m13253/danmaku2ass and typcn/danmaku2ass_native. Much respect to the authors.

Supported Website

Currently only Bilibili is supported. Other websites will be added in the future.

Usage

As executable

Download the binaries from Releases page, then make it executable.

Usage: danmaku2ass [-h] [-o OUTPUT] [-s WIDTHxHEIGHT] [-fn FONT]
                   [-fs SIZE] [-a ALPHA] [-dm SECONDS] [-ds SECONDS]
                   FILE

positional arguments:
  FILE                  Comment file to be processed

optional arguments:
  -h, --help            show this help message and exit
  -o OUTPUT, --output OUTPUT
                        Output file
  -s WIDTHxHEIGHT, --size WIDTHxHEIGHT
                        Stage size in pixels [default: 1280x720]
  -fn FONT, --font FONT
                        Specify font face [default: sans-serif]
  -fs SIZE, --fontsize SIZE
                        Default font size [default: 25]
  -a ALPHA, --alpha ALPHA
                        Text opacity [default: 1]
  -dm SECONDS, --duration-marquee SECONDS
                        Duration of scrolling comment display [default: 5]
  -ds SECONDS, --duration-still SECONDS
                        Duration of still comment display [default: 5]

As library

Download the code and place it into your project, then import it in your CMakeLists.txt:

add_subdirectory(danmaku2ass)
include_directories(${PROJECT_SOURCE_DIR}/3rdparty/danmaku2ass/include)
......
target_link_libraries(${TARGET_NAME} Danmaku2AssCPP)

C-compatible API:

#include <Danmaku2ASS/danmaku2ass.h>

void danmaku2ass(const char *infile,    // Input file
                 const char *outfile,   // Output file
                 int width,             // Video width
                 int height,            // Video height
                 const char *font,      // Font name
                 int fontsize,          // Font size
                 double alpha,          // Transparency [0-1]
                 int duration_marquee,  // Display time of scrolling comments
                 int duration_still);   // Display time of still comments

Use in C++:

#include <Danmaku2ASS/CommentParser.h>
#include <Danmaku2ASS/AssBuilder.h>
#include <fstream>

void danmaku2ass_example()
{
    // Open source file
    std::ifstream input("danmaku.xml");
    Danmaku2ASS::CommentParser parser(input);

    // Set parameters
    parser.setResolution(1280, 720); // Video size
    parser.setFont("Heiti", 32);     // Font name & size
    parser.setDuration(5, 5);        // Display time of scrolling and still comments
    parser.setAlpha(alpha);          // Transparency [0-1]

    // Convert to ASS
    Danmaku2ASS::AssBuilder::Ptr ass = parser.convert();

    if (ass != nullptr)
    {
        // Block scolling and top comments
        ass->setDisallowMode(Danmaku2ASS::DISALLOW_SCROLL | Danmaku2ASS::DISALLOW_TOP);

        // Block words
        std::vector<std::string> blockWords = {"114514"};
        ass->setBlockWords(blockWords);

        // Reserve 20% of bottom area for subtitles
        ass->setReservedArea(0.2);

        // Save to file
        std::ofstream outfile("output.ass");
        ass->exportAss(outfile);
    }
}

Render danmaku into videos

Use ffmpeg:

ffmpeg -i foo.flv -vf ass=foo.ass -vcodec libx264 -acodec copy foo-with-danmaku.flv

Licence

Do What The F*ck You Want To