fix(discord): resample audio to 48kHz for voice messages by kevinWangSheng · Pull Request #32298 · openclaw/openclaw

kevinWangSheng · 2026-03-02T23:37:53Z

Fixes #32293: Discord voice message plays at ~0.5x speed with 24kHz TTS source

When TTS providers (like mlx-audio Qwen3-TTS) output audio at 24kHz, Discord voice messages play at half speed because Discord expects 48kHz.

This fix adds explicit sample rate conversion to 48kHz in the ensureOggOpus function, ensuring voice messages always play at correct speed regardless of the input audio's sample rate.

Fixes openclaw#32293: Discord voice message plays at ~0.5x speed with 24kHz TTS source When TTS providers (like mlx-audio Qwen3-TTS) output audioHz, Discord voice at 24k messages play at half speed because Discord expects 48kHz. This fix adds explicit sample rate conversion to 48kHz in the ensureOggOpus function, ensuring voice messages always play at correct speed regardless of the input audio's sample rate.

aisle-research-bot · 2026-03-02T23:38:00Z

🔒 Aisle Security Analysis

We found 1 potential security issue(s) in this PR:

#	Severity	Title
1	🔵 Low	Unbounded ffmpeg processing in voice message conversion can cause resource-exhaustion (DoS)

1. 🔵 Unbounded ffmpeg processing in voice message conversion can cause resource-exhaustion (DoS)

Property	Value
Severity	Low
CWE	CWE-400
Location	`src/discord/voice-message.ts:190-201`

Description

ensureOggOpus() invokes ffmpeg on attacker-controlled audio content without any execution timeout or duration/size limits.

Impact:

A crafted/very long audio file (even if relatively small on disk due to low bitrate) can trigger very long transcoding time and high CPU usage.
Because execFile is used without a timeout, ffmpeg can run indefinitely (or for an attacker-chosen duration), tying up worker capacity.

Vulnerable code:

await execFileAsync("ffmpeg", [
  "-y",
  "-i",
  filePath,
  "-ar",
  "48000",
  "-c:a",
  "libopus",
  "-b:a",
  "64k",
  outputPath,
]);

Recommendation

Add hard limits around transcoding:

Enforce a maximum input duration (and/or reject unusually long audio early):

const duration = await getAudioDuration(filePath);
if (duration > 120) throw new Error("Voice messages must be <= 120s");

Apply a timeout to the ffmpeg invocation (either by passing timeout to execFile, or by switching to the existing runCommandWithTimeout() helper):

import { runCommandWithTimeout } from "../process/exec.js";

await runCommandWithTimeout([
  "ffmpeg",
  "-y",
  "-i", filePath,
  "-t", "120",           // cap work
  "-ar", "48000",
  "-c:a", "libopus",
  "-b:a", "64k",
  outputPath,
], { timeoutMs: 30_000 });

Optionally also reduce worst-case probing costs:

Use -analyzeduration / -probesize caps
Disable non-audio streams with -vn -sn -dn

Analyzed PR: #32298 at commit 09ec684

_{Last updated on: 2026-03-02T23:47:23Z}

greptile-apps · 2026-03-02T23:40:39Z

Greptile Summary

This PR fixes half-speed Discord voice message playback (issue #32293) by adding -ar 48000 to the ffmpeg command in ensureOggOpus, ensuring audio is resampled to 48kHz before Opus encoding. The fix is correct and sufficient for the most common case (non-OGG or OGG-Vorbis inputs).

Key concern:

The early-return path for files already in OGG/Opus format (lines 162–181) returns the file as-is without checking its declared sample rate. A 24kHz OGG/Opus file — which some TTS providers can produce natively — would bypass the new resampling step entirely and still play at half speed in Discord. The ffprobe call at that path should be extended to also verify the sample rate is 48kHz, falling through to full conversion if it is not.

Confidence Score: 3/5

Safe to merge with the caveat that the fix is incomplete for 24kHz OGG/Opus inputs.
The added -ar 48000 flag correctly fixes the reported issue for the majority of TTS inputs (e.g., WAV/MP3/OGG-Vorbis at 24kHz). However, the OGG/Opus early-return path still skips resampling regardless of the file's actual sample rate, meaning the same playback bug can still occur when the input is already OGG/Opus-encoded at a non-48kHz rate. The fix is not fully complete.
src/discord/voice-message.ts — the OGG/Opus early-return block (lines 162–181) needs a sample-rate check.

_{Last reviewed commit: 09ec684}

greptile-apps

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

greptile-apps · 2026-03-02T23:40:47Z

Additional Comments (1)

src/discord/voice-message.ts
Early-return bypasses 48kHz resampling for existing OGG/Opus files

The fix correctly adds -ar 48000 to the conversion path, but the early-return for files that are already OGG/Opus at line 176-178 still returns the file unchanged — without verifying its sample rate. If a TTS provider outputs OGG/Opus natively at 24kHz, this path will skip resampling and Discord will still play the audio at half speed, because the OGG header declares 24kHz and Discord honours that declared rate.

To be fully consistent with the fix's intent, the OGG/Opus fast-path should also verify the stream's sample rate with ffprobe and fall through to conversion when it isn't 48kHz:

if (ext === ".ogg") {
  try {
    const { stdout: codecOut } = await execFileAsync("ffprobe", [
      "-v", "error",
      "-select_streams", "a:0",
      "-show_entries", "stream=codec_name,sample_rate",
      "-of", "csv=p=0",
      filePath,
    ]);
    const [codec, sampleRate] = codecOut.trim().toLowerCase().split(",");
    if (codec === "opus" && sampleRate === "48000") {
      return { path: filePath, cleanup: false };
    }
    // else: fall through to conversion (wrong codec or wrong sample rate)
  } catch {
    // If probe fails, convert anyway
  }
}

Without this change the bug described in the linked issue can still surface whenever the input is already in OGG/Opus container but encoded at a sample rate other than 48kHz.

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/discord/voice-message.ts
Line: 162-181

Comment:
**Early-return bypasses 48kHz resampling for existing OGG/Opus files**

The fix correctly adds `-ar 48000` to the conversion path, but the early-return for files that are already OGG/Opus at line 176-178 still returns the file unchanged — without verifying its sample rate. If a TTS provider outputs OGG/Opus natively at 24kHz, this path will skip resampling and Discord will still play the audio at half speed, because the OGG header declares 24kHz and Discord honours that declared rate.

To be fully consistent with the fix's intent, the OGG/Opus fast-path should also verify the stream's sample rate with `ffprobe` and fall through to conversion when it isn't 48kHz:

```typescript
if (ext === ".ogg") {
  try {
    const { stdout: codecOut } = await execFileAsync("ffprobe", [
      "-v", "error",
      "-select_streams", "a:0",
      "-show_entries", "stream=codec_name,sample_rate",
      "-of", "csv=p=0",
      filePath,
    ]);
    const [codec, sampleRate] = codecOut.trim().toLowerCase().split(",");
    if (codec === "opus" && sampleRate === "48000") {
      return { path: filePath, cleanup: false };
    }
    // else: fall through to conversion (wrong codec or wrong sample rate)
  } catch {
    // If probe fails, convert anyway
  }
}
```

Without this change the bug described in the linked issue can still surface whenever the input is already in OGG/Opus container but encoded at a sample rate other than 48kHz.

How can I resolve this? If you propose a fix, please make it concise.

steipete · 2026-03-03T01:01:26Z

Landed.

Gate: pnpm vitest run src/discord/voice/command.test.ts src/discord/send.sends-basic-channel-messages.test.ts src/discord/send.components.test.ts
Merge commit: 924d9e3

Thanks @kevinWangSheng!

) Fixes openclaw#32293: Discord voice message plays at ~0.5x speed with 24kHz TTS source When TTS providers (like mlx-audio Qwen3-TTS) output audioHz, Discord voice at 24k messages play at half speed because Discord expects 48kHz. This fix adds explicit sample rate conversion to 48kHz in the ensureOggOpus function, ensuring voice messages always play at correct speed regardless of the input audio's sample rate. Co-authored-by: Kevin Shenghui <[email protected]>

) Fixes openclaw#32293: Discord voice message plays at ~0.5x speed with 24kHz TTS source When TTS providers (like mlx-audio Qwen3-TTS) output audioHz, Discord voice at 24k messages play at half speed because Discord expects 48kHz. This fix adds explicit sample rate conversion to 48kHz in the ensureOggOpus function, ensuring voice messages always play at correct speed regardless of the input audio's sample rate. Co-authored-by: Kevin Shenghui <[email protected]> (cherry picked from commit 924d9e3)

) Fixes openclaw#32293: Discord voice message plays at ~0.5x speed with 24kHz TTS source When TTS providers (like mlx-audio Qwen3-TTS) output audioHz, Discord voice at 24k messages play at half speed because Discord expects 48kHz. This fix adds explicit sample rate conversion to 48kHz in the ensureOggOpus function, ensuring voice messages always play at correct speed regardless of the input audio's sample rate. Co-authored-by: Kevin Shenghui <[email protected]>

openclaw-barnacle bot added channel: discord Channel integration: discord size: XS trusted-contributor labels Mar 2, 2026

greptile-apps bot reviewed Mar 2, 2026

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steipete mentioned this pull request Mar 2, 2026

fix(cli): auto-build when dist missing in npx github: source #32300

Closed

steipete merged commit 924d9e3 into openclaw:main Mar 3, 2026
30 checks passed

github-actions bot mentioned this pull request Mar 3, 2026

📡 Upstream Digest — 2026-03-03 01:23 UTC curtismercier/openclaw-mods#168

Open

alexey-pelykh mentioned this pull request Mar 10, 2026

Cherry-pick: Discord & Slack adapter fixes (audio resample 48kHz, voice ffmpeg opus, connected status, session routing, auth fail-fast) remoteclaw/remoteclaw#779

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fix(discord): resample audio to 48kHz for voice messages#32298

fix(discord): resample audio to 48kHz for voice messages#32298
steipete merged 1 commit intoopenclaw:mainfrom
kevinWangSheng:fix/discord-voice-24khz

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🔒 Aisle Security Analysis

1. 🔵 Unbounded ffmpeg processing in voice message conversion can cause resource-exhaustion (DoS)

Description

Recommendation

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greptile-apps bot commented Mar 2, 2026

Greptile Summary

Confidence Score: 3/5

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