在Rockchip上使用libav(ffmpeg)并调用rkmpp硬件加速。#

// main.zig
const std = @import("std");

const c = @cImport({
    @cInclude("libavcodec/avcodec.h");
    @cInclude("libavutil/avutil.h");
});

const HW_TAGS = [_][]const u8{
    "nvenc",
    "qsv",
    "vaapi",
    "amf",
    "videotoolbox",
    "v4l2m2m",
    "omx",
    "rkmpp",
    "mediacodec",
    "mmal",
};

fn isHwEncoder(name: []const u8) bool {
    var buf: [256]u8 = undefined;

    // std.ascii.lowerString 会 assert(output.len >= input.len)，先防一下
    const lower: []const u8 = if (name.len <= buf.len)
        std.ascii.lowerString(&buf, name)
    else
        name; // 超长就退化为原串（一般 codec 名都很短）

    for (HW_TAGS) |tag| {
        if (std.mem.indexOf(u8, lower, tag) != null) return true;
    }
    return false;
}

const Item = struct {
    name: []u8,
    long_name: ?[]u8,
};

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const alloc = gpa.allocator();

    var iter: ?*anyopaque = null;

    // Zig 0.15+: ArrayList 用 .empty，所有操作显式传 allocator
    var found: std.ArrayList(Item) = .empty;
    defer {
        for (found.items) |it| {
            alloc.free(it.name);
            if (it.long_name) |ln| alloc.free(ln);
        }
        found.deinit(alloc);
    }

    while (true) {
        const codec: ?*const c.AVCodec = c.av_codec_iterate(&iter);
        if (codec == null) break;

        if (c.av_codec_is_encoder(codec) == 0) continue;
        if (codec.?.type != c.AVMEDIA_TYPE_VIDEO) continue;

        const cname = std.mem.span(codec.?.name);
        if (!isHwEncoder(cname)) continue;

        const name_copy = try alloc.dupe(u8, cname);

        var long_copy: ?[]u8 = null;
        if (codec.?.long_name != null) {
            const clong = std.mem.span(codec.?.long_name);
            long_copy = try alloc.dupe(u8, clong);
        }

        try found.append(alloc, .{ .name = name_copy, .long_name = long_copy });
    }

    // Zig 0.15.1+ 新 stdout 写法：提供 buffer + flush
    var stdout_buffer: [4096]u8 = undefined;
    var stdout_writer = std.fs.File.stdout().writer(&stdout_buffer);
    const out = &stdout_writer.interface;

    if (found.items.len == 0) {
        try out.print("没有检测到硬件视频编码器（来自已链接的 libavcodec）。\n", .{});
        try out.flush();
        return;
    }

    try out.print("当前可用的硬件视频编码器（来自 libavcodec）：\n", .{});
    for (found.items) |it| {
        if (it.long_name) |ln| {
            try out.print("- {s}: {s}\n", .{ it.name, ln });
        } else {
            try out.print("- {s}\n", .{it.name});
        }
    }

    try out.flush();
}

const std = @import("std");

pub fn build(b: *std.Build) void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

    const sysroot_opt = b.option([]const u8, "sysroot", "Sysroot path (e.g. /mnt/rk3588)");

    const mod = b.createModule(.{
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });

    const exe = b.addExecutable(.{
        .name = "hwenc_list",
        .root_module = mod,
    });

    // 你项目里有 @cImport + @cInclude，需要 libc
    exe.linkLibC(); // 官方文档/示例做法 :contentReference[oaicite:1]{index=1}

    // 如果提供了 sysroot，就把头文件/库路径加进去
    if (sysroot_opt) |sysroot| {
        // ---- headers: IMPORTANT (multiarch first) ----
        mod.addIncludePath(.{ .cwd_relative = b.fmt("{s}/usr/include/aarch64-linux-gnu", .{sysroot}) });
        mod.addIncludePath(.{ .cwd_relative = b.fmt("{s}/usr/include", .{sysroot}) });
        mod.addIncludePath(.{ .cwd_relative = b.fmt("{s}/include", .{sysroot}) });

        // ---- libraries: put multiarch first ----
        exe.addLibraryPath(.{ .cwd_relative = b.fmt("{s}/usr/lib/aarch64-linux-gnu", .{sysroot}) });
        exe.addLibraryPath(.{ .cwd_relative = b.fmt("{s}/lib/aarch64-linux-gnu", .{sysroot}) });
        exe.addLibraryPath(.{ .cwd_relative = b.fmt("{s}/usr/lib", .{sysroot}) });
        exe.addLibraryPath(.{ .cwd_relative = b.fmt("{s}/lib", .{sysroot}) });
    }

    // 链接 FFmpeg / libav（官方“Linking to System Libraries”示例就是 exe.linkSystemLibrary） :contentReference[oaicite:2]{index=2}
    exe.linkSystemLibrary("avcodec");
    exe.linkSystemLibrary("avutil");

    // 常见依赖（缺啥报错再补）
    exe.linkSystemLibrary("z");
    exe.linkSystemLibrary("m");
    exe.linkSystemLibrary("pthread");
    exe.linkSystemLibrary("dl");

    b.installArtifact(exe);

    // 可选：zig build run
    const run_cmd = b.addRunArtifact(exe);
    if (b.args) |args| run_cmd.addArgs(args);
    b.step("run", "Run the app").dependOn(&run_cmd.step);
}