To crop a pre-recorded video in OBS, add it as a Media Source, select it, then hold Alt on Windows or Linux—or Option on macOS—and drag an edge of its bounding box. For measured adjustments, use Edit Transform and enter crop values there.
Cropping changes which part of that source appears in the scene. It does not require you to change the configured YouTube stream resolution: keep the intended size in Settings > Video > Output (Scaled) Resolution, and check the composition on the canvas before you go live.
Add the clip as a Media Source
In the scene where you want the clip to appear, go to the Sources panel, select the add control, and choose Media Source. Give the source a name that will make sense later, such as “Opening loop” or “Temple view”, then point it to the video file. OBS uses Media Sources to add audio and video files to a scene.
The file is a source in the scene, rather than a replacement for the stream canvas. You can move, crop, or scale that source within the composition while keeping the canvas and configured output size separate. For a channel that uses several prerecorded clips, a descriptive source name also makes it easier to tell which item you are adjusting when the Sources panel grows.
If your plan is to play several files in sequence, make sure the workflow you choose suits that job: a single Media Source is a convenient way to place a file in a scene, while a folder or playlist needs its own playback arrangement. The guide to streaming a folder of gaming videos to YouTube Live covers that different use case. The crop steps here apply to a selected source, not to the entire playlist as one newly edited video.
Before adjusting anything, confirm that the right scene is active and the clip appears in the preview. If the source has not loaded, check its file path and playback state first; dragging a nonexistent or inactive source will not solve a media-loading problem. You do not need to alter output resolution just to make the file fit visually.
Select the source in the scene
Select the Media Source either by clicking its name in the Sources list or by clicking the visible clip in the preview. When selected, OBS shows a bounding box around it. That box identifies the source transform you are about to edit; make sure it surrounds the clip rather than another source, such as a background image, logo, or text overlay.
If sources overlap, choosing the item in the Sources list is often more reliable than clicking the preview. The list can also help you check visibility: a hidden source will not show in the composition even if it is present in the scene. Select the clip you intend to reframe, then look for its bounding box before using a crop gesture.
Cropping is easy to confuse with resizing. A normal drag on a bounding-box handle changes the source's size or shape in the scene; the crop gesture instead trims the visible edges of the selected source. If the box does not appear, select the source again. If the wrong element gets a box, undo or reset that element before continuing.
You can use OBS's source transform commands for common placement tasks. The Sources Guide lists commands such as Fit to Screen, Center to Screen, and Reset Transform, with platform-specific keyboard shortcuts. Those commands affect how the source sits in the scene; they do not change the configured stream output size. The OBS Sources Guide is the primary reference for the source controls and their shortcuts.
Crop edges with Alt or Option dragging
With the Media Source selected, hold Alt on Windows or Linux, or Option on macOS, and drag one of the bounding-box edges inward in the preview. OBS marks crop edges green while you are cropping. Release the mouse button when the unwanted edge area is out of view, then release the modifier key. Repeat on another edge if the framing needs trimming on more than one side.
The modifier matters. Without it, dragging a handle may resize or reshape the source rather than crop it. Work slowly enough to see the green crop indication, especially if the preview is small. If the source moves instead of trimming, undo the change and try again with the source selected and the correct modifier held before you start dragging.
There is no universal crop amount for a particular kind of clip. A bhajan video with subtitles near the lower edge, a news loop with a ticker, and a lofi animation with a centred subject all have different useful boundaries. Crop only what you intend to hide, and check that essential text, faces, or visual details remain visible. A crop that looks tidy on one file can cut off useful content in another.
This gesture is useful when you are visually composing one clip and want a quick result. It is less suitable when you need to reproduce the same measured crop later, or when a colleague needs to inspect exact values. In those cases, use Edit Transform instead of estimating the edges from the preview.
Enter exact crop values in Edit Transform
For more precise or repeatable adjustments, open the selected source's Transform menu and choose Edit Transform. OBS presents transform controls for the source, including crop values. Enter the amount to trim from the relevant edges, then close the dialog and inspect the result in the preview. The Sources Guide also lists Ctrl-E for Edit Transform on Windows and the corresponding Cmd shortcut on macOS.
Use the numeric route when you have a known framing to reproduce, or when a visual drag is difficult to judge. For example, if the clip contains a narrow strip of unwanted black border on its left edge, a numeric crop lets you make a deliberate change and revisit it later. Avoid treating any particular value as a general recommendation: pixel dimensions and content vary from file to file.
Check each edge independently. A crop value removes visible area from the source; it does not add content elsewhere or guarantee that the remaining image fills the canvas. After entering values, the source may need repositioning or resizing to sit as intended. Those are separate composition adjustments, so make them after confirming the crop itself.
If you are not sure what changed, reopen Edit Transform and inspect the values rather than making a series of untracked drags. Reset Transform is available when you need to return the source transform to its default state, but use it cautiously if you have already made useful positioning or scaling changes. The official OBS Sources Guide documents the transform route and related controls.
Keep the intended output resolution
OBS has distinct settings for the workspace and for the outgoing image. Base (Canvas) Resolution defines the canvas where you arrange sources. Output (Scaled) Resolution defines the dimensions OBS sends to the stream or recording. Source crop is a further, separate operation: it hides parts of a selected source inside that composition.
To keep the intended YouTube stream size, open Settings > Video and check Output (Scaled) Resolution. Leave it at the value you have chosen for the channel. Cropping one clip does not mean that this setting needs to change. The OBS Studio Overview Guide explains the distinction between base and output resolutions and notes that changing output size does not require sources to be realigned or resized; changing the base canvas can require those adjustments.
That distinction is useful when a clip has a different shape from the canvas. Suppose you have a wide canvas and a tall phone video: cropping can hide some of the phone video, while source positioning and sizing determine how the remaining picture sits on the canvas. The stream still uses the configured output dimensions. It may show unused space if the source does not cover the canvas, but that is a framing issue rather than a reason to change output resolution automatically.
If you are deciding what size the channel should send in the first place, make that decision for the overall stream, not to fix the edges of one file. The guide to streaming a 24/7 YouTube channel in different resolutions discusses that broader choice. For cropping, return to the source and scene controls once the output setting is where you want it.
Check framing and source bounds
After cropping, inspect all four edges in the preview. Check the subject's position, any captions, logos or ticker text, and whether the crop exposes an edge you meant to hide. A crop can make the visible portion smaller without changing the file itself; moving or scaling the source afterwards may reveal a different part of the original image or leave an empty area on the canvas.
If you see an unintended gap, first inspect the source's crop and its position and size in Edit Transform. Confirm that the visible source area is placed where you expect. Do not change Output (Scaled) Resolution merely because one source is not filling the canvas: that changes the dimensions sent to the stream or recording, not the source's crop boundary.
Keep the distinction between source bounds and canvas bounds in mind. The source bounds describe the clip as an item in the scene; the canvas is the workspace that contains all scene items. A source can be smaller than the canvas, larger than it, or positioned partly outside it. Cropping trims what that source contributes, while the composition decides how it sits alongside other elements.
For a filter-based workflow, OBS also offers a Crop/Pad effect filter. It is optional; you do not need to add it for the basic Alt/Option gesture or Edit Transform process. OBS's Crop/Pad and scaling information describes source-level filters, and the Scaling/Aspect Ratio Filter guide explains another optional source-level control. A filter can be useful when you specifically want a filter in the source's stack, but it is not a shortcut for changing the stream canvas.
Do a final check after any move or scale adjustment. A crop that looked correct before repositioning can leave a subject too close to an edge once the whole source is shifted. Preview the actual scene with its other layers visible, rather than judging the cropped file in isolation.
Preview the stream composition
Before you leave the scene running, look at the complete composition: the cropped clip, overlays, background, and any text or branding. Check at the same preview size and aspect as the canvas where possible. Confirm that the important part of the clip remains visible and that no source overlaps something it should not cover.
Then check that the file plays as expected and that its audio behaviour suits the channel. A clean crop cannot fix a file that stops, has unwanted audio, or begins with a blank frame. If the scene is part of a continuous broadcast, include this review in the wider pre-flight checks before leaving a 24/7 stream running. That checklist is a useful companion because framing is only one part of a reliable overnight setup.
For a manually operated OBS broadcast, keep OBS open while you test the stream and watch the YouTube preview as well as the local canvas. For a prerecorded channel where the recurring burden is keeping a computer on and restarting a dropped broadcast, StreamNeo removes that specific need by running an uploaded video as a YouTube live stream while your computer is off. It is YouTube-only; it does not replace OBS when you need a live multi-source production or want to mix changing inputs.
If the goal is not just to crop a source in a fixed scene but to create a new standalone video file with a different frame size, use a video editing or export workflow. OBS scene cropping is not an export operation and does not alter the encoded canvas dimensions by itself. Keep that distinction clear when choosing whether you need a source adjustment, a scene layout change, or a newly rendered file.
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FAQ
How do I crop a video source in OBS and keep my YouTube stream at the same resolution?
Select the Media Source and hold Alt while dragging an edge on Windows or Linux, or Option on macOS. For a measured crop, choose Edit Transform and enter values. Keep the chosen size in Settings > Video > Output (Scaled) Resolution; cropping the source does not require changing that output setting.
Why does dragging a handle resize the video instead of cropping it?
The crop gesture requires the correct modifier key: Alt on Windows or Linux, Option on macOS. Select the source first, then hold the key while dragging an edge and look for OBS's green crop indication. If the source moved or resized, undo and repeat with the modifier held before dragging.
Can the same crop values be used for every video?
No. The useful crop depends on the source's dimensions and where its subject, captions, or other important details sit. Inspect each file and choose values that trim only the area you intend to hide.
Does Edit Transform change the YouTube stream resolution?
No. Edit Transform adjusts the selected source's transform and crop within the scene. Output (Scaled) Resolution controls the dimensions sent to the stream or recording, so leave it at the intended value when you are only reframing a clip.