Slow/warbly audio when sending Opus packets parsed from file to voice channel

[kausikk]

Hi, I have a simple program that directly parses Opus packets from a file and transmits them with the "OpusSend" channel, but the audio through Discord sounds as if it's been slowed down and comes out extremely warbly. Any idea on what the issue could be? Issue happens even when using PR #1593 or #1677.

package main
import (
	"os"
	"io"
	"time"
	"github.com/bwmarrin/discordgo"
)
...
func main() {
	s, err := discordgo.New(BOT_TOKEN)
	...
	s.Identify.Intents = 1 << 7 | 1 << 20 | 1 << 21 // Guild voice states | Connect | Speak
	...
	err = s.Open()
	...
	vc, err := s.ChannelVoiceJoin(GUILD_ID, VOICE_CHNL_ID, false, true)
	...
	f, err := os.Open(OPUS_PATH)
	...
	time.Sleep(1000 * time.Millisecond)
	vc.Speaking(true)
	time.Sleep(1000 * time.Millisecond)
	...
	// Parse Opus pages
	for {
		// Parse page header
		n, err := io.ReadFull(f, headerBuf[:])
		...
		// Discard first two pages since these
		// contain metadata
		if discard < 2 {
			...
			discard += 1
			continue
		}
		// Parse packets
		for i := 0; i < tableLen; i++ {
			...
			_, err = io.ReadFull(f, packetBuf[pEnd:pEnd+segLen])
			...
			vc.OpusSend <- packetBuf[:pEnd]
			...
		}
	}
	vc.Disconnect()
}

Full code here: music.go
Sample song here: VcOSUOpACq0.opus

To verify that the Opus packets are correct, I made a small Go program which replicates my parsing implementation and pipes packets to a discord.py script which connects to a voice channel and transmits the audio packets. The discord.py implementation works fine.