go - 如何二进制读取 Opus 文件

Question

在仍在学习 Go 的过程中，我正在尝试正确读取 Opus 文件并将其发送到 Discord 的语音 channel 。 (仅支持 Opus 编解码器)。最初使用 this我能够传递一个 WAV，该脚本会将其编码为 Opus，然后通过 channel 将其发送到 Discord。相反，我想发送一个现成的 Opus 文件。然而，相反，我听到了乱码，这意味着我在阅读它时做错了什么。

这是一个精简但完整的示例(减去电子邮件、密码和服务器 ID)，奇迹发生在 playSong .我觉得这与我的音频缓冲区有关，但仍然在学习技巧。

读取作品文件并将其传递给 channel 的正确方法是什么？如果需要一个opus文件来测试，找一个here .任何帮助表示赞赏。谢谢!

package main

import (
    "encoding/binary"
    "fmt"
    "io"
    "os"
    "os/exec"
    "runtime"
    "strings"

    "github.com/bwmarrin/discordgo"
    "github.com/oleiade/lane"
)

type voiceInstancesMap map[string]*VoiceInstance

var (
    run            *exec.Cmd
    voiceInstances = voiceInstancesMap{}
)

const (
    email     string = ""
    password  string = ""
    serverID  string = ""
    channels  int    = 2     // 1 for mono, 2 for stereo
    frameRate int    = 48000 // audio sampling rate
)

type VoiceInstance struct {
    discord  *discordgo.Session
    queue    *lane.Queue
    serverID string
}

func (vi *VoiceInstance) playSong() {
    f, err := os.Open("./test.opus")
    defer f.Close()

    audiobuf := make([]byte, 1024)

    vi.discord.Voice.Speaking(true)
    defer vi.discord.Voice.Speaking(false)

    for {
        err = binary.Read(f, binary.LittleEndian, &audiobuf)
        if err == io.EOF || err == io.ErrUnexpectedEOF {
            break
        }
        if err != nil {
            fmt.Println("error reading from ffmpeg stdout :", err)
            break
        }

        fmt.Println("Sending audio")
        vi.discord.Voice.OpusSend <- audiobuf
    }
}

func (vi *VoiceInstance) connectVoice() {
    vi.discord, _ = discordgo.New(email, password)

    // Open the websocket and begin listening.
    err := vi.discord.Open()
    if err != nil {
        fmt.Println(err)
    }

    channels, err := vi.discord.GuildChannels(vi.serverID)

    var voiceChannel string
    voiceChannels := []string{}
    for _, channel := range channels {
        if channel.Type == "voice" {
            voiceChannels = append(voiceChannels, channel.ID)
            if strings.Contains(strings.ToLower(channel.Name), "music") && voiceChannel == "" {
                voiceChannel = channel.ID
            }
        }
    }

    if voiceChannel == "" {
        fmt.Println("Selecting first channel")
        voiceChannel = voiceChannels[0]
    }

    err = vi.discord.ChannelVoiceJoin(vi.serverID, voiceChannel, false, true)
    if err != nil {
        fmt.Println(err)
        return
    }

    // Hacky loop to prevent sending on a nil channel.
    // TODO: Find a better way.
    for vi.discord.Voice.Ready == false {
        runtime.Gosched()
    }
}

func main() {
    vi := new(VoiceInstance)
    voiceInstances[serverID] = vi

    fmt.Println("Connecting Voice...")
    vi.serverID = serverID
    vi.queue = lane.NewQueue()
    vi.connectVoice()
    vi.playSong()
}

Answer 1

使用https://github.com/hraban/opus .从该链接的文档中:
要解码 .opus 文件(或带有 Opus 数据的 .ogg)，或解码“Opus 流”(带有 Opus 数据的 Ogg 流)，请使用 Stream 接口(interface)。它包装了一个 io.Reader 提供原始流字节并返回解码的 Opus 数据。
从 .opus 文件中读取的粗略示例:

f, err := os.Open(fname)
if err != nil {
    ...
}
s, err := opus.NewStream(f)
if err != nil {
    ...
}
defer s.Close()
buf := make([]byte, 16384)
for {
    n, err = s.Read(buf)
    if err == io.EOF {
        break
    } else if err != nil {
        ...
    }
    pcm := buf[:n*channels]

    // send pcm to audio device here, or write to a .wav file

}