To keep audio synced in a looping 4K 60fps YouTube Live stream, first confirm the video file is in sync on its own, then add it to OBS as a Media Source with Loop enabled. Make sure its audio reaches the active stream mix, and test the full playback—including the loop transition—before going live. A constant offset may be corrected with a small source sync adjustment; audio drift that grows over time or appears at every loop needs diagnosis, not an arbitrary delay.
Find out whether the file or the stream is out of sync
Before changing OBS settings, play the original file locally from beginning to end. Compare visible events—such as a spoken word, clap, or musical beat—with their sound at the start, near the end, and across the point where playback will restart. If the audio and video already diverge in the file, or the ending does not transition cleanly to the beginning, OBS can repeat the file but cannot make its contents intrinsically seamless.
Audio that is consistently late or early is a different problem from audio that gradually drifts or jumps at the loop boundary. Note which pattern you hear; it determines what to troubleshoot next.
Set up a single-file loop in OBS
- Add the file: In the scene you intend to stream, add a Media Source and select the local video file.
- Enable looping: In the Media Source properties, turn on Loop. OBS restarts the file after playback completes. For a playlist rather than a single file, OBS also documents VLC Video with Loop Playlist; VLC must be installed for that source.
- Check the audio path: Play the source and look for its meter activity in the OBS audio mixer. Confirm it is not muted and that the source is routed to the audio mix being sent to YouTube.
- Keep the test setup representative: Use the same scene, output frame rate, encoder, audio path, and file you plan to use on air. Changing those between the test and broadcast can make the test less useful.
OBS labels may differ between releases. OBS documents Media Source looping and supported media sources in its Media Sources guide; its Audio Sources guide and Audio Mixer guide cover routing and mixer behavior.
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#1 Best Overall
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Test the complete stream, including the loop point
Run a private or unlisted YouTube test with audio and movement similar to the planned broadcast. Listen through OBS monitoring, inspect a local OBS recording, and watch the received YouTube stream. Check the beginning, middle, final moments, and the next playback start. YouTube recommends testing with representative audio and motion and monitoring stream health and messages during the event.
Use what you observe to choose the next step:
- The same offset persists throughout: Measure whether the affected audio is early or late. Adjust the sync timing for the affected source in small increments, then repeat the entire test. Avoid delaying all audio if only the Media Source is out of sync.
- The offset grows during playback: Check the file’s timestamps and encoding, the source timing, decoding load, and whether audio sample rates are consistent along the capture path. The official guidance does not establish one cause or one corrective value that works for every file and setup.
- The mismatch appears at each restart: Recheck the file’s final and opening moments, including their audio durations, and observe the source as playback restarts. A fixed delay cannot correct a discontinuity that occurs only at the loop boundary.
- OBS shows dropped frames or an unstable connection: Investigate the network and whether the connection can sustain the selected bitrate. OBS says dropped frames indicate connection instability or a bitrate the link cannot sustain; dropped frames alone do not prove the cause of audio drift. See OBS’s dropped-frames troubleshooting guide.
Use YouTube’s 4K60 ingest settings as a starting point
YouTube’s encoder guidance lists the following recommendations for a 4K/2160p, 60 fps stream. They describe YouTube ingest settings—not a guarantee that a particular computer or internet connection can sustain them. Test upload stability before relying on a high bitrate.
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| Setting | YouTube guidance for 4K/2160p at 60 fps |
|---|---|
| H.264 video bitrate | 35 Mbps recommended |
| AV1 or H.265 video bitrate | 10–40 Mbps recommended range |
| Rate control | CBR |
| Keyframe interval | 2 seconds recommended; do not exceed 4 seconds |
| Frame rate | Up to 60 fps |
| Audio format and bitrate | AAC or MP3; 128 kbps stereo or 384 kbps 5.1 recommended |
| Audio sample rate | 44.1 kHz for stereo; 48 kHz for 5.1 surround |
| Ingest protocol | RTMPS recommended |
| Latency | 4K/2160 streams do not offer “improve for low latency” and are optimized for normal latency |
These figures and constraints come from YouTube’s encoder settings for live streaming; the page does not state a publication date. The 35 Mbps figure is YouTube’s recommended H.264 video bitrate, not a total upload-speed target. Leave room for connection variation and other network use, and confirm stream health during the test. The 4K latency limitation means this workflow should not be planned around a low-latency setting.
Troubleshoot likely causes without masking the symptom
- No audio meter movement: Check that the Media Source is playing, unmuted, and routed to the active stream mix. Confirm the stream’s selected audio track includes that mix.
- Audio is out of sync from the beginning by a steady amount: Verify the local file first, then adjust only the affected source’s timing and retest from the start through a loop.
- Sync worsens over time: Revisit file timestamps and encoding, source timing, decoding load, and audio sample-rate consistency. Do not assume lowering bitrate will fix sync; YouTube’s ingest recommendations do not establish that as a remedy.
- Sync breaks only when the video restarts: Inspect the last and first moments of the source and their audio boundaries. Repeatedly applying a constant offset will not remove a loop-specific discontinuity.
- Stream health reports dropped frames: Check connection stability and whether the configured bitrate is sustainable, using OBS’s connection troubleshooting guidance. Treat this as a network/bitrate signal, not proof of the audio-sync cause.
A wired Ethernet connection can help when the existing network link is unstable, and headphones can make a preflight listening check easier. Neither can correct a timing problem in the media file or OBS source.
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- 【Package Content & Note】 1x HD Audio Capture Card , 1x USB 3.0 to USB C Adapter (A-side 3.0, B-side 2.0), 1x user manual. Please note that you need to restart the OBS Studio software after the audio setup is complete, otherwise it will result in no sound output. When using an adapter, if the device is recognized as USB 2.0, try using the other side with the USB-C port. Simply flip the capture card and reconnect it to be recognized as USB 3.0
Or let it run in the cloud
If your goal is to keep uploaded videos looping on YouTube Live without leaving a computer running, StreamNeo uploads and loops video from the cloud: upload your recording or build a playlist, add your YouTube stream key, and go live. Nothing has to stay on at home; the upload streams as made up to 4K 60fps at one flat price per slot, and StreamNeo automatically recovers if YouTube drops the stream. Each slot includes 10 GB of storage, pooled across active slots. The first day is free with no card, once per account. The monthly price is $9.99 per month. This is for uploaded video streaming to YouTube, not a live camera feed. Start your free day with StreamNeo.
Quick Recap
Rank #4
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