c_src/blend2d_video.cpp

#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <iostream>

#ifdef _WIN32
#include <windows.h>
#define BL_VIDEO_EXPORT __declspec(dllexport)
#else
#include <dlfcn.h>
#define BL_VIDEO_EXPORT __attribute__((visibility("default")))
#endif

// ============================================================================
// Exact FFmpeg C Types (Matching FFmpeg 6.x / 7.x ABI)
// ============================================================================

#define AV_PIX_FMT_YUV420P 0
#define AV_PIX_FMT_ARGB    25
#define AV_PIX_FMT_RGBA    26
#define AV_PIX_FMT_BGRA    28

#define SWS_FAST_BILINEAR 1
#define SWS_BILINEAR      2
#define SWS_BICUBIC       4

#define AVIO_FLAG_WRITE 2
#define AVFMT_NOFILE 0x0001
#define AVFMT_GLOBALHEADER 0x0040
#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
#define AVMEDIA_TYPE_VIDEO 0

#define AVERROR_EAGAIN -11
#define AVERROR_EOF    -541478725

struct AVRational {
    int num;
    int den;
};

struct AVStream {
    int index;
    int id;
    void* codecpar;
    AVRational time_base;
    int64_t start_time;
    int64_t duration;
    int64_t nb_frames;
    int64_t cur_dts;
    void* metadata;
    AVRational avg_frame_rate;
    AVRational r_frame_rate;
    AVRational sample_aspect_ratio;
    int nb_side_data;
    void* side_data;
};

struct AVOutputFormat {
    const char* name;
    const char* long_name;
    const char* mime_type;
    const char* extensions;
    int audio_codec;
    int video_codec;
    int subtitle_codec;
    int flags;
};

struct AVFormatContext {
    const void* av_class;
    void* iformat;
    AVOutputFormat* oformat;
    void* priv_data;
    void* pb;
    int ctx_flags;
    unsigned int nb_streams;
    AVStream** streams;
};

struct AVCodecContext {
    const void* av_class;
    int log_level_offset;
    int codec_type;
    const void* codec;
    int codec_id;
    unsigned int codec_tag;
    void* priv_data;
    void* internal;
    void* opaque;
    int64_t bit_rate;
    int bit_rate_tolerance;
    int global_quality;
    int compression_level;
    int flags;
    int flags2;
    uint8_t* extradata;
    int extradata_size;
    AVRational time_base;
    int ticks_per_frame;
    int delay;
    int width, height;
    int coded_width, coded_height;
    AVRational sample_aspect_ratio;
    int pix_fmt;
};

struct AVFrame {
    uint8_t* data[8];
    int linesize[8];
    uint8_t** extended_data;
    int width, height;
    int nb_samples;
    int format;
    int key_frame;
    int pict_type;
    AVRational sample_aspect_ratio;
    int64_t pts;
    int64_t pkt_dts;
    AVRational time_base;
};

struct AVPacket {
    void* buf;
    int64_t pts;
    int64_t dts;
    uint8_t* data;
    int size;
    int stream_index;
    int flags;
    void* side_data;
    int side_data_elems;
    int64_t duration;
    int64_t pos;
    void* opaque;
    void* opaque_ref;
    AVRational time_base;
};

// ============================================================================
// FFmpeg Function Pointer Declarations
// ============================================================================

typedef int (*fn_avformat_alloc_output_context2)(AVFormatContext** ctx, void* oformat, const char* format_name, const char* filename);
typedef AVStream* (*fn_avformat_new_stream)(AVFormatContext* s, const void* c);
typedef int (*fn_avformat_write_header)(AVFormatContext* s, void** options);
typedef int (*fn_av_write_trailer)(AVFormatContext* s);
typedef int (*fn_avio_open)(void** s, const char* url, int flags);
typedef int (*fn_avio_closep)(void** s);
typedef int (*fn_av_interleaved_write_frame)(AVFormatContext* s, AVPacket* pkt);
typedef void (*fn_avformat_free_context)(AVFormatContext* s);

typedef void* (*fn_avcodec_find_encoder_by_name)(const char* name);
typedef void* (*fn_avcodec_find_encoder)(int id);
typedef void* (*fn_avcodec_alloc_context3)(const void* codec);
typedef void (*fn_avcodec_free_context)(void** avctx);
typedef int (*fn_avcodec_open2)(void* avctx, const void* codec, void** options);
typedef int (*fn_avcodec_send_frame)(void* avctx, const AVFrame* frame);
typedef int (*fn_avcodec_receive_packet)(void* avctx, AVPacket* pkt);
typedef int (*fn_avcodec_parameters_from_context)(void* par, const void* codec);

typedef AVFrame* (*fn_av_frame_alloc)();
typedef void (*fn_av_frame_free)(AVFrame** frame);
typedef int (*fn_av_frame_get_buffer)(AVFrame* frame, int align);
typedef int (*fn_av_frame_make_writable)(AVFrame* frame);

typedef AVPacket* (*fn_av_packet_alloc)();
typedef void (*fn_av_packet_free)(AVPacket** pkt);
typedef void (*fn_av_packet_rescale_ts)(AVPacket* pkt, AVRational tb_src, AVRational tb_dst);
typedef void (*fn_av_packet_unref)(AVPacket* pkt);

typedef int (*fn_av_opt_set)(void* obj, const char* name, const char* val, int search_flags);
typedef int (*fn_av_opt_set_int)(void* obj, const char* name, int64_t val, int search_flags);
typedef int (*fn_av_opt_set_q)(void* obj, const char* name, AVRational val, int search_flags);
typedef int (*fn_av_opt_set_pixel_fmt)(void* obj, const char* name, int fmt, int search_flags);

typedef int (*fn_av_dict_set)(void** pm, const char* key, const char* value, int flags);
typedef void (*fn_av_dict_free)(void** pm);

typedef void* (*fn_sws_getContext)(int srcW, int srcH, int srcFormat, int dstW, int dstH, int dstFormat, int flags, void* srcFilter, void* dstFilter, const double* param);
typedef int (*fn_sws_scale)(void* c, const uint8_t* const srcSlice[], const int srcStride[], int srcSliceY, int srcSliceH, uint8_t* const dst[], const int dstStride[]);
typedef void (*fn_sws_freeContext)(void* swsContext);

struct FFmpegAPI {
    bool loaded = false;
    fn_avformat_alloc_output_context2 avformat_alloc_output_context2 = nullptr;
    fn_avformat_new_stream avformat_new_stream = nullptr;
    fn_avformat_write_header avformat_write_header = nullptr;
    fn_av_write_trailer av_write_trailer = nullptr;
    fn_avio_open avio_open = nullptr;
    fn_avio_closep avio_closep = nullptr;
    fn_av_interleaved_write_frame av_interleaved_write_frame = nullptr;
    fn_avformat_free_context avformat_free_context = nullptr;

    fn_avcodec_find_encoder_by_name avcodec_find_encoder_by_name = nullptr;
    fn_avcodec_find_encoder avcodec_find_encoder = nullptr;
    fn_avcodec_alloc_context3 avcodec_alloc_context3 = nullptr;
    fn_avcodec_free_context avcodec_free_context = nullptr;
    fn_avcodec_open2 avcodec_open2 = nullptr;
    fn_avcodec_send_frame avcodec_send_frame = nullptr;
    fn_avcodec_receive_packet avcodec_receive_packet = nullptr;
    fn_avcodec_parameters_from_context avcodec_parameters_from_context = nullptr;

    fn_av_frame_alloc av_frame_alloc = nullptr;
    fn_av_frame_free av_frame_free = nullptr;
    fn_av_frame_get_buffer av_frame_get_buffer = nullptr;
    fn_av_frame_make_writable av_frame_make_writable = nullptr;

    fn_av_packet_alloc av_packet_alloc = nullptr;
    fn_av_packet_free av_packet_free = nullptr;
    fn_av_packet_rescale_ts av_packet_rescale_ts = nullptr;
    fn_av_packet_unref av_packet_unref = nullptr;

    fn_av_opt_set av_opt_set = nullptr;
    fn_av_opt_set_int av_opt_set_int = nullptr;
    fn_av_opt_set_q av_opt_set_q = nullptr;
    fn_av_opt_set_pixel_fmt av_opt_set_pixel_fmt = nullptr;

    fn_av_dict_set av_dict_set = nullptr;
    fn_av_dict_free av_dict_free = nullptr;

    fn_sws_getContext sws_getContext = nullptr;
    fn_sws_scale sws_scale = nullptr;
    fn_sws_freeContext sws_freeContext = nullptr;
};

static FFmpegAPI g_ff;

#ifdef _WIN32
static void* load_sym(HMODULE mod, const char* name) {
    return (void*)GetProcAddress(mod, name);
}
#else
static void* load_sym(void* mod, const char* name) {
    return dlsym(mod, name);
}
#endif

extern "C" {

BL_VIDEO_EXPORT int bl_video_init_ffmpeg(
    const char* avcodec_path,
    const char* avformat_path,
    const char* avutil_path,
    const char* swscale_path
) {
    if (g_ff.loaded) return 0;

#ifdef _WIN32
    HMODULE h_util = LoadLibraryA(avutil_path ? avutil_path : "avutil-59.dll");
    HMODULE h_codec = LoadLibraryA(avcodec_path ? avcodec_path : "avcodec-61.dll");
    HMODULE h_format = LoadLibraryA(avformat_path ? avformat_path : "avformat-61.dll");
    HMODULE h_sws = LoadLibraryA(swscale_path ? swscale_path : "swscale-8.dll");
#else
    void* h_util = dlopen(avutil_path ? avutil_path : "libavutil.so", RTLD_NOW | RTLD_GLOBAL);
    void* h_codec = dlopen(avcodec_path ? avcodec_path : "libavcodec.so", RTLD_NOW | RTLD_GLOBAL);
    void* h_format = dlopen(avformat_path ? avformat_path : "libavformat.so", RTLD_NOW | RTLD_GLOBAL);
    void* h_sws = dlopen(swscale_path ? swscale_path : "libswscale.so", RTLD_NOW | RTLD_GLOBAL);
#endif

    if (!h_util || !h_codec || !h_format || !h_sws) {
        return -1;
    }

    g_ff.avformat_alloc_output_context2 = (fn_avformat_alloc_output_context2)load_sym(h_format, "avformat_alloc_output_context2");
    g_ff.avformat_new_stream = (fn_avformat_new_stream)load_sym(h_format, "avformat_new_stream");
    g_ff.avformat_write_header = (fn_avformat_write_header)load_sym(h_format, "avformat_write_header");
    g_ff.av_write_trailer = (fn_av_write_trailer)load_sym(h_format, "av_write_trailer");
    g_ff.avio_open = (fn_avio_open)load_sym(h_format, "avio_open");
    g_ff.avio_closep = (fn_avio_closep)load_sym(h_format, "avio_closep");
    g_ff.av_interleaved_write_frame = (fn_av_interleaved_write_frame)load_sym(h_format, "av_interleaved_write_frame");
    g_ff.avformat_free_context = (fn_avformat_free_context)load_sym(h_format, "avformat_free_context");

    g_ff.avcodec_find_encoder_by_name = (fn_avcodec_find_encoder_by_name)load_sym(h_codec, "avcodec_find_encoder_by_name");
    g_ff.avcodec_find_encoder = (fn_avcodec_find_encoder)load_sym(h_codec, "avcodec_find_encoder");
    g_ff.avcodec_alloc_context3 = (fn_avcodec_alloc_context3)load_sym(h_codec, "avcodec_alloc_context3");
    g_ff.avcodec_free_context = (fn_avcodec_free_context)load_sym(h_codec, "avcodec_free_context");
    g_ff.avcodec_open2 = (fn_avcodec_open2)load_sym(h_codec, "avcodec_open2");
    g_ff.avcodec_send_frame = (fn_avcodec_send_frame)load_sym(h_codec, "avcodec_send_frame");
    g_ff.avcodec_receive_packet = (fn_avcodec_receive_packet)load_sym(h_codec, "avcodec_receive_packet");
    g_ff.avcodec_parameters_from_context = (fn_avcodec_parameters_from_context)load_sym(h_codec, "avcodec_parameters_from_context");

    g_ff.av_frame_alloc = (fn_av_frame_alloc)load_sym(h_util, "av_frame_alloc");
    g_ff.av_frame_free = (fn_av_frame_free)load_sym(h_util, "av_frame_free");
    g_ff.av_frame_get_buffer = (fn_av_frame_get_buffer)load_sym(h_util, "av_frame_get_buffer");
    g_ff.av_frame_make_writable = (fn_av_frame_make_writable)load_sym(h_util, "av_frame_make_writable");

    g_ff.av_packet_alloc = (fn_av_packet_alloc)load_sym(h_codec, "av_packet_alloc");
    if (!g_ff.av_packet_alloc) g_ff.av_packet_alloc = (fn_av_packet_alloc)load_sym(h_util, "av_packet_alloc");

    g_ff.av_packet_free = (fn_av_packet_free)load_sym(h_codec, "av_packet_free");
    if (!g_ff.av_packet_free) g_ff.av_packet_free = (fn_av_packet_free)load_sym(h_util, "av_packet_free");

    g_ff.av_packet_rescale_ts = (fn_av_packet_rescale_ts)load_sym(h_codec, "av_packet_rescale_ts");
    if (!g_ff.av_packet_rescale_ts) g_ff.av_packet_rescale_ts = (fn_av_packet_rescale_ts)load_sym(h_util, "av_packet_rescale_ts");

    g_ff.av_packet_unref = (fn_av_packet_unref)load_sym(h_codec, "av_packet_unref");
    if (!g_ff.av_packet_unref) g_ff.av_packet_unref = (fn_av_packet_unref)load_sym(h_util, "av_packet_unref");

    g_ff.av_opt_set = (fn_av_opt_set)load_sym(h_util, "av_opt_set");
    g_ff.av_opt_set_int = (fn_av_opt_set_int)load_sym(h_util, "av_opt_set_int");
    g_ff.av_opt_set_q = (fn_av_opt_set_q)load_sym(h_util, "av_opt_set_q");
    g_ff.av_opt_set_pixel_fmt = (fn_av_opt_set_pixel_fmt)load_sym(h_util, "av_opt_set_pixel_fmt");

    g_ff.av_dict_set = (fn_av_dict_set)load_sym(h_util, "av_dict_set");
    g_ff.av_dict_free = (fn_av_dict_free)load_sym(h_util, "av_dict_free");

    g_ff.sws_getContext = (fn_sws_getContext)load_sym(h_sws, "sws_getContext");
    g_ff.sws_scale = (fn_sws_scale)load_sym(h_sws, "sws_scale");
    g_ff.sws_freeContext = (fn_sws_freeContext)load_sym(h_sws, "sws_freeContext");

    g_ff.loaded = (g_ff.avformat_alloc_output_context2 && g_ff.avcodec_send_frame && g_ff.sws_scale);
    return g_ff.loaded ? 0 : -2;
}

// ============================================================================
// Blend2D Native C++ Video Encoder
// ============================================================================

struct BLVideoEncoder {
    AVFormatContext* format_ctx = nullptr;
    void* codec_ctx = nullptr;
    AVStream* stream = nullptr;
    void* sws_ctx = nullptr;
    AVFrame* frame = nullptr;
    AVPacket* pkt = nullptr;
    int width = 0;
    int height = 0;
    double fps = 30.0;
    int64_t pts = 0;
    int64_t frame_count = 0;
    bool is_open = false;
    char last_error[256] = {0};
};

BL_VIDEO_EXPORT BLVideoEncoder* bl_video_encoder_create(
    const char* filename,
    int width,
    int height,
    double fps,
    const char* codec_name,
    int crf,
    const char* preset,
    int bitrate
) {
    if (!g_ff.loaded || !filename || width <= 0 || height <= 0 || fps <= 0.0) {
        return nullptr;
    }

    auto* enc = new BLVideoEncoder();
    enc->width = (width % 2 == 0) ? width : width - 1;
    enc->height = (height % 2 == 0) ? height : height - 1;
    enc->fps = fps;
    enc->pts = 0;
    enc->frame_count = 0;

    // 1. Allocate output format context
    int ret = g_ff.avformat_alloc_output_context2(&enc->format_ctx, nullptr, nullptr, filename);
    if (ret < 0 || !enc->format_ctx) {
        snprintf(enc->last_error, sizeof(enc->last_error), "Could not deduce format for: %s", filename);
        delete enc;
        return nullptr;
    }

    // 2. Find video encoder
    const void* codec = nullptr;
    if (codec_name && strlen(codec_name) > 0) {
        codec = g_ff.avcodec_find_encoder_by_name(codec_name);
    }
    if (!codec) {
        codec = g_ff.avcodec_find_encoder_by_name("libx264");
    }
    if (!codec) {
        codec = g_ff.avcodec_find_encoder(enc->format_ctx->oformat->video_codec);
    }
    if (!codec) {
        snprintf(enc->last_error, sizeof(enc->last_error), "No suitable video encoder found");
        g_ff.avformat_free_context(enc->format_ctx);
        delete enc;
        return nullptr;
    }

    // 3. Create video stream
    enc->stream = g_ff.avformat_new_stream(enc->format_ctx, nullptr);
    if (!enc->stream) {
        snprintf(enc->last_error, sizeof(enc->last_error), "Failed to allocate stream");
        g_ff.avformat_free_context(enc->format_ctx);
        delete enc;
        return nullptr;
    }
    enc->stream->id = enc->format_ctx->nb_streams - 1;

    // 4. Allocate codec context
    enc->codec_ctx = g_ff.avcodec_alloc_context3(codec);
    if (!enc->codec_ctx) {
        snprintf(enc->last_error, sizeof(enc->last_error), "Failed to allocate codec context");
        g_ff.avformat_free_context(enc->format_ctx);
        delete enc;
        return nullptr;
    }

    // Set properties via AVOptions
    g_ff.av_opt_set_int(enc->codec_ctx, "width", enc->width, 0);
    g_ff.av_opt_set_int(enc->codec_ctx, "height", enc->height, 0);
    
    AVRational tb = {1, (int)(fps * 1000)};
    g_ff.av_opt_set_q(enc->codec_ctx, "time_base", tb, 0);
    enc->stream->time_base = tb;

    AVRational fr = {(int)fps, 1};
    g_ff.av_opt_set_q(enc->codec_ctx, "framerate", fr, 0);
    
    // Set pixel format
    if (g_ff.av_opt_set_pixel_fmt) {
        g_ff.av_opt_set_pixel_fmt(enc->codec_ctx, "pix_fmt", AV_PIX_FMT_YUV420P, 0);
    } else {
        g_ff.av_opt_set(enc->codec_ctx, "pix_fmt", "yuv420p", 0);
    }

    if (bitrate > 0) {
        g_ff.av_opt_set_int(enc->codec_ctx, "b", bitrate, 0);
    }

    // CRF and Preset
    void* opts = nullptr;
    if (preset && strlen(preset) > 0) {
        g_ff.av_dict_set(&opts, "preset", preset, 0);
    } else {
        g_ff.av_dict_set(&opts, "preset", "fast", 0);
    }
    if (crf >= 0) {
        char crf_str[16];
        snprintf(crf_str, sizeof(crf_str), "%d", crf);
        g_ff.av_dict_set(&opts, "crf", crf_str, 0);
    }

    // 5. Open codec
    ret = g_ff.avcodec_open2(enc->codec_ctx, codec, &opts);
    g_ff.av_dict_free(&opts);
    if (ret < 0) {
        snprintf(enc->last_error, sizeof(enc->last_error), "Failed to open video codec");
        g_ff.avcodec_free_context(&enc->codec_ctx);
        g_ff.avformat_free_context(enc->format_ctx);
        delete enc;
        return nullptr;
    }

    if (enc->stream->codecpar) {
        g_ff.avcodec_parameters_from_context(enc->stream->codecpar, enc->codec_ctx);
    }

    // 6. Open file
    if (!(enc->format_ctx->oformat->flags & AVFMT_NOFILE)) {
        ret = g_ff.avio_open(&enc->format_ctx->pb, filename, AVIO_FLAG_WRITE);
        if (ret < 0) {
            snprintf(enc->last_error, sizeof(enc->last_error), "Could not open file: %s", filename);
            g_ff.avcodec_free_context(&enc->codec_ctx);
            g_ff.avformat_free_context(enc->format_ctx);
            delete enc;
            return nullptr;
        }
    }

    // 7. Write header
    ret = g_ff.avformat_write_header(enc->format_ctx, nullptr);
    if (ret < 0) {
        snprintf(enc->last_error, sizeof(enc->last_error), "Failed to write header");
        if (enc->format_ctx->pb) g_ff.avio_closep(&enc->format_ctx->pb);
        g_ff.avcodec_free_context(&enc->codec_ctx);
        g_ff.avformat_free_context(enc->format_ctx);
        delete enc;
        return nullptr;
    }

    // 8. Allocate frame
    enc->frame = g_ff.av_frame_alloc();
    enc->frame->format = AV_PIX_FMT_YUV420P;
    enc->frame->width = enc->width;
    enc->frame->height = enc->height;
    g_ff.av_frame_get_buffer(enc->frame, 0);

    // 9. Allocate SIMD SwsContext
    enc->sws_ctx = g_ff.sws_getContext(
        enc->width, enc->height, AV_PIX_FMT_BGRA,
        enc->width, enc->height, AV_PIX_FMT_YUV420P,
        SWS_FAST_BILINEAR, nullptr, nullptr, nullptr
    );

    enc->pkt = g_ff.av_packet_alloc();
    enc->is_open = true;
    return enc;
}

BL_VIDEO_EXPORT int bl_video_encoder_write_raw(
    BLVideoEncoder* enc,
    const uint8_t* bgra_data,
    int stride
) {
    if (!enc || !enc->is_open || !bgra_data) return -1;

    if (g_ff.av_frame_make_writable(enc->frame) < 0) {
        return -2;
    }

    const uint8_t* src_slices[4] = { bgra_data, nullptr, nullptr, nullptr };
    int src_strides[4] = { stride, 0, 0, 0 };

    g_ff.sws_scale(
        enc->sws_ctx,
        src_slices, src_strides, 0, enc->height,
        enc->frame->data, enc->frame->linesize
    );

    enc->frame->pts = enc->frame_count * 1000;
    enc->frame_count++;

    int ret = g_ff.avcodec_send_frame(enc->codec_ctx, enc->frame);
    if (ret < 0) return ret;

    while (ret >= 0) {
        ret = g_ff.avcodec_receive_packet(enc->codec_ctx, enc->pkt);
        if (ret == AVERROR_EAGAIN || ret == AVERROR_EOF) {
            break;
        } else if (ret < 0) {
            return ret;
        }

        g_ff.av_packet_rescale_ts(enc->pkt, enc->stream->time_base, enc->stream->time_base);
        enc->pkt->stream_index = enc->stream->id;

        ret = g_ff.av_interleaved_write_frame(enc->format_ctx, enc->pkt);
        g_ff.av_packet_unref(enc->pkt);
        if (ret < 0) return ret;
    }

    return 0;
}

BL_VIDEO_EXPORT int bl_video_encoder_close(BLVideoEncoder* enc) {
    if (!enc || !enc->is_open) return 0;

    g_ff.avcodec_send_frame(enc->codec_ctx, nullptr);
    while (g_ff.avcodec_receive_packet(enc->codec_ctx, enc->pkt) == 0) {
        g_ff.av_packet_rescale_ts(enc->pkt, enc->stream->time_base, enc->stream->time_base);
        enc->pkt->stream_index = enc->stream->id;
        g_ff.av_interleaved_write_frame(enc->format_ctx, enc->pkt);
        g_ff.av_packet_unref(enc->pkt);
    }

    if (enc->format_ctx) {
        g_ff.av_write_trailer(enc->format_ctx);
    }

    if (enc->codec_ctx) {
        g_ff.avcodec_free_context(&enc->codec_ctx);
    }
    if (enc->frame) {
        g_ff.av_frame_free(&enc->frame);
    }
    if (enc->pkt) {
        g_ff.av_packet_free(&enc->pkt);
    }
    if (enc->sws_ctx) {
        g_ff.sws_freeContext(enc->sws_ctx);
        enc->sws_ctx = nullptr;
    }
    if (enc->format_ctx) {
        if (!(enc->format_ctx->oformat->flags & AVFMT_NOFILE) && enc->format_ctx->pb) {
            g_ff.avio_closep(&enc->format_ctx->pb);
        }
        g_ff.avformat_free_context(enc->format_ctx);
        enc->format_ctx = nullptr;
    }

    enc->is_open = false;
    return 0;
}

BL_VIDEO_EXPORT void bl_video_encoder_destroy(BLVideoEncoder* enc) {
    if (enc) {
        if (enc->is_open) {
            bl_video_encoder_close(enc);
        }
        delete enc;
    }
}

BL_VIDEO_EXPORT int64_t bl_video_encoder_get_frame_count(const BLVideoEncoder* enc) {
    return enc ? enc->frame_count : 0;
}

BL_VIDEO_EXPORT const char* bl_video_encoder_get_last_error(const BLVideoEncoder* enc) {
    return enc ? enc->last_error : "Null encoder";
}

} // extern "C"