If a clip only needs to play in an OBS scene, add it as a Media Source and set its playback and audio routing there; you do not need to change the video file. If another part of your workflow specifically requires an audio stream inside the file, use FFmpeg to mux generated silence alongside the video.
Those are different jobs. A silent track does not create audible content, and YouTube's published encoder guidance does not say that every live stream needs one. First identify what is asking for an audio stream, then choose the least disruptive fix.
Decide where silence belongs
Start by asking what you need to achieve. If you are putting a video into an OBS scene and want it to contribute no sound, OBS can play the file while you mute or route its audio as appropriate. If a downstream player, editing workflow, or ingest path specifically expects the file to expose an audio stream, then changing the file may be justified.
| What you need | Best starting point | Does the original file change? | Main check |
|---|---|---|---|
| Play a clip in an OBS scene without hearing its audio | Add a Media Source and manage its audio in OBS | No | Check the Audio Mixer and test the scene |
| Repeat a clip as a visual loop | Set the Media Source playback controls | No | Confirm the loop and restart behaviour |
| Deliver a file that contains video and a silent audio stream | Generate silence and mux it with FFmpeg | Yes, a new output file is created | Inspect both streams and play the output |
| Diagnose a YouTube audio warning | Check OBS routing and the current YouTube guidance first | Not necessarily | Test the actual encoder path |
A file can already have an audio stream, even if its content is quiet, silent, or not wanted in the stream. Adding it to OBS does not remove that audio. Conversely, muting a source in OBS changes what that scene sends, not the streams stored in the source file.
If you are unsure whether the file must change, try the OBS-only route first. It is easier to reverse and keeps the source file intact. A useful distinction is whether the requirement concerns what viewers hear from the live scene or what a separate application detects when it examines the video file.
For a continuous playlist rather than one clip, the playback problem may be about what happens between items, not missing audio. The guide to keeping a YouTube lofi stream playing when a track ends covers that separate hand-off problem. If the material is a worship service, the article on streaming pre-recorded worship services without a PC running is a better fit for the larger operating choice.
Add the clip as an OBS Media Source
In OBS, use the Sources dock to select +, then choose Media Source. Give it a recognisable name, such as “Opening prayer clip” or “Study loop”, and select the local video file. OBS documents Media Sources and the available playback controls in its Media Sources guide.
For a source you want to reuse in a scene, decide whether to create a new source or use an existing one when OBS offers that choice. A distinct source name helps when a scene contains a background loop, a title card and a short announcement. It also makes it less likely that you change the wrong source later.
OBS lists common video types including MP4, TS, MOV, FLV, MKV, AVI, GIF and WebM. Supported extensions do not guarantee every combination of codec, container and file will behave as expected on your computer. If the source does not load or seek properly, note the container and codec before reaching for a conversion; an audio change will not fix a video-decoding problem.
Set the source's visibility and position in the scene. If the clip should fill the canvas, use the usual OBS transform controls and check the preview for cropping. A Media Source can be resized or placed like other visual sources, so adding an audio stream to the file is not a way to make it appear on screen.
Keep a copy of the original somewhere you can find it. OBS references the file you select; if you move or rename it later, the source may no longer locate it. For a long-running channel, use a stable folder and a clear filename rather than leaving the only copy in a temporary downloads location.
Configure playback and audio routing
Open the Media Source properties and choose the playback behaviour that matches the clip. For a recurring visual loop, enable looping. If the clip should start again each time the scene becomes active, use the restart option. These controls affect OBS playback; neither option edits the file.
Next inspect the Audio Mixer while the source plays. A meter moving means OBS is receiving audio from that source, not necessarily that viewers should hear it. Mute the source in the mixer if it must contribute no sound, or configure the intended routing if its audio is wanted. If you mute it, check that you have not muted a different source with a similar name.
OBS's Sources guide explains how sources are added and arranged, while the Quick Start Guide recommends checking the mixer and testing settings before streaming. The practical point is to watch the meters during playback and confirm the scene's output, rather than assuming a file has no audio because you cannot hear it locally.
If the source has no audio stream, its meter may not behave like a source with an active track. If it has an existing track, muting in OBS prevents that source audio from reaching the mix, but does not delete or rewrite the track. Keep the distinction clear when another operator later opens the same file outside OBS.
Pay attention to other audio sources in the scene: a microphone, desktop audio, browser source, or another media source may still be audible. A “silent video” scene can therefore have sound even when the clip itself is muted. Use headphones or a controlled test recording to check the complete mix, and review the monitor and output settings if you need to listen to a source locally without sending it to the stream.
Generate silence with FFmpeg when the file needs a track
Use FFmpeg only when the deliverable itself needs an audio stream. Its anullsrc filter provides a null audio source; the documented options include channel layout and sample rate, and it can generate audio for a specified duration or indefinitely. The FFmpeg documentation describes anullsrc; the command below combines that source with an input video.
ffmpeg -i input.mp4 -f lavfi -i anullsrc=r=48000:cl=stereo -map 0:v:0 -map 1:a:0 -c:v copy -c:a aac -shortest output.mp4
Replace input.mp4 with the actual filename and choose an output name that does not overwrite the original. This example selects the first input's first video stream and the generated second input's first audio stream. It copies the video rather than encoding it again, encodes the silent audio as AAC, and stops when the shortest input ends.
The values in the example are settings for a particular workflow, not a universal requirement. YouTube's live encoder guidance lists AAC and MP3 as audio codecs for RTMP/RTMPS, and provides separate recommendations for stereo and 5.1 audio. Its live encoder settings page should be checked against the encoder and ingest path you actually use. A format accepted for one workflow does not prove the whole file is suitable for another.
With -shortest, output duration follows the shorter of the video and generated audio. Because anullsrc without a finite duration can continue indefinitely, that option prevents an endless generated track from keeping the muxing process running after the video ends. It also means you should verify the resulting duration instead of assuming it matches an intended schedule.
If FFmpeg reports a container or codec error, do not remove stream mapping as a guess. Check the output container and codec compatibility, then adjust the output deliberately. Keep the source untouched until the output has been inspected and played. If you are not comfortable using a command line, and the need is only to keep a clip quiet in a live scene, return to OBS routing instead.
Map and mux the intended streams
The mapping options determine exactly which streams enter the output. -map 0:v:0 selects the first video's video stream, and -map 1:a:0 selects the generated audio stream from the second input. This is why explicit mapping matters when the original file already has audio: the command does not accidentally carry that original audio into the new file.
If you want to preserve an existing audio track rather than replace it with silence, the example is not the right command as written. You would need to select and map the intended original audio stream explicitly, along with the video, and consider whether re-encoding or copying is appropriate for the target container. Do not assume FFmpeg's automatic stream selection matches your purpose.
-c:v copy avoids re-encoding the video, which generally saves a processing step and avoids introducing a new video encode. It cannot make an incompatible video codec compatible with a container or destination, and it does not repair a damaged source. The audio encoder option in the example writes AAC audio; the actual result should still be checked in the target player and workflow.
FFmpeg's stream selection and muxing documentation explains mapping and stream handling. The command here is an illustrative combination of documented options, not a guarantee that every file will work unchanged. If the source has multiple video tracks, subtitles, attachments or unusual metadata, this simple mapping deliberately leaves them out. Add only the streams you need, and preserve other material only after confirming the intended result.
Muxing means placing encoded streams together in a container; it does not mean the silence becomes audible. A silent stream carries no intended programme sound. If the goal is simply a quiet live broadcast, muting or routing in OBS is usually clearer than creating and maintaining another copy of each video.
Check the output file's streams
After the command completes, inspect the output with a media information tool such as ffprobe, which is distributed with FFmpeg. Confirm that it reports a video stream and an audio stream, and check the codecs, channel layout, sample rate and duration against the intended workflow. The presence of a track alone is not enough if the output container or codec is unsuitable.
Then play the file from beginning to end, or at least across points where you know a problem might show up. Confirm that the picture starts, stays in sync and reaches its expected end. Check that the audio stream is present but does not introduce an unwanted noise or retained programme audio. A silent track should not be treated as proof of silence; listening to the output is a useful check for mapping mistakes.
If you use a graphical media player, its display of audio tracks can help but may not expose all technical details. If ffprobe is unavailable or unfamiliar, another inspection tool can confirm the streams; keep a record of the filename you checked so you do not accidentally load the unmodified source into OBS.
Container and codec compatibility still matters. OBS's Audio/Video Formats Guide notes format considerations, including AAC compatibility with MP4 and the flexibility of MKV for recordings. That does not mean every video stream can be copied into every container. Test the exact output in the application that will use it.
Keep the original and muxed output clearly differentiated, for example clip-original.mp4 and clip-silent-audio.mp4. If you later edit the picture, repeat the check on the new export; the old muxed file will not update itself. This small file-management habit avoids a common source of confusion when multiple versions are in a scene collection.
Test the clip in the intended OBS workflow
Before a scheduled broadcast, open the actual OBS scene and test the exact file you intend to use. Confirm picture, looping, restart behaviour and audio routing. Watch the mixer while the clip plays, and verify that other sources in the scene behave as expected. A clip tested in a separate media player has not yet tested OBS's scene configuration.
If the stream is sent to YouTube, do a representative test with similar picture movement and audio behaviour to the planned programme. YouTube's live streaming tips advise testing and monitoring the stream; its encoder guidance also describes supported settings. Check the current official pages before relying on a particular codec or setting because platform requirements can change.
Do not infer from the codec list that a silent audio track is mandatory for every YouTube live stream. If a message or device in your chain asks for audio, identify exactly where it appears: file inspection, OBS, the encoder, or YouTube's live control room. A warning in one layer may point to a configuration issue rather than a need to rewrite every file.
For a channel that runs continuously, the test should cover how the scene behaves when you switch away and return, not just the first few seconds after opening it. Verify that the source restarts or continues as you intend, and that your next scene does not leave an unexpected audio source active. If your wider setup needs a failover plan, see the guide to configuring an OBS backup stream key for YouTube failover; that is a separate resilience question from whether this file contains silence.
If the reason you are avoiding file edits is that a computer should not have to stay on, a file conversion alone will not solve that operating issue. StreamNeo can remove the need to keep OBS running on your own computer for a file-based continuous broadcast, while leaving you responsible for choosing and checking the video and channel setup.
Before committing, compare the operating options on the pricing page. When the file and channel are ready, start free — 24-hour trial, no card.
FAQ
Does YouTube Live require a silent audio track?
The cited YouTube encoder guidance lists acceptable audio codecs for RTMP/RTMPS but does not establish that every stream must contain an audio track. Check the current official guidance and the specific warning from your encoder or ingest path before changing the file.
How do I add silent audio in OBS without changing the video?
Add the clip as a Media Source, configure its playback controls and mute or route its audio in the OBS mixer as needed. This changes the scene's output, not the streams inside the video file.
Will adding a silent track make the video audible?
No. The generated track is silence, so it does not add music, speech or other audible content. Check the output for accidentally retained audio if the original file already had a track.
Why does FFmpeg need stream mapping here?
Mapping tells FFmpeg which video and audio streams to put in the output, rather than relying on automatic selection. In the example, it uses the source video and generated audio, leaving any original audio out.