If vMix playlist videos look wrongly shaped on YouTube, start by checking Settings > Display > Output Aspect Ratio, then compare the stream’s encode dimensions with the selected shape. vMix documents widescreen inputs appearing letterboxed when Output Aspect Ratio is set to Normal (4:3) rather than Widescreen (16:9).
First establish where the bars or distortion appear: in vMix’s output, only in YouTube playback, or only with one playlist item. These checks trace the vMix configuration path; they do not verify YouTube’s current handling of every stream with mismatched dimensions, and they cannot guarantee that every aspect-ratio problem will be resolved.
Check where the bars appear
Before changing a setting, look at the same moment in the playlist in more than one place: vMix’s preview and output, any local recording or other output you can inspect, and YouTube playback. You are trying to locate where the picture first looks wrong. If it is already letterboxed in vMix, begin with vMix’s output settings. If vMix looks right but YouTube does not, keep the cause open and check what is being encoded before drawing conclusions about the platform.
Be precise about the visible fault. Letterboxing means the picture has bars above and below it, or sometimes at the sides. Cropping means part of the picture is missing, such as a face or text being cut off near an edge. Stretching means shapes look unnaturally wide or tall. The vMix support material cited here describes letterboxing and also notes cropping with a custom square or vertical stream aspect ratio; it does not establish that stretching is the cause in your case.
Now ask whether every input is affected or only one item. If cameras, graphics and multiple videos all show the same bars, a master output setting is a sensible early check. If only one playlist item looks wrong, compare it with another item and inspect its dimensions and framing. That comparison is a troubleshooting inference, not a documented List Input-specific repair.
vMix describes List Input as supporting lists of video, audio and M3U playlist files played as one input. That makes it useful to separate a shared output issue from a source-specific one, but the cited material does not document a separate aspect-ratio control for List Input. Don’t assume that changing a playlist control will correct an incorrectly framed file.
If the fault appears only on YouTube, note the exact playback location and whether the stream’s outgoing dimensions are what you expect. The sources used for this guide do not verify YouTube’s current treatment of mismatched dimensions. Avoid changing several settings at once: you want to know whether the vMix output itself changed, not merely whether a later playback looks different.
Open vMix Display settings
In vMix, open Settings from the top-right area and select Display. Find Output Aspect Ratio. vMix’s support explanation identifies Normal as 4:3 and Widescreen as 16:9; it describes a widescreen source appearing with bars above and below when the output is set to Normal.
Use the intended shape of the programme, not the shape you happen to see after a problem has occurred. For a conventional widescreen channel made from 16:9 videos or camera feeds, Widescreen is the relevant setting to inspect. If you deliberately produce a 4:3 programme, Normal may be intentional. A setting is not wrong merely because its name differs from the aspect ratio of an individual file; it is wrong when it does not match the output you mean to make.
The exact symptom matters. The documented example is a widescreen input, such as a 1920 x 1080 video or camera, inside an output configured as 4:3, with bars above and below. If that describes your vMix output, check this setting before trying to crop or edit the source. Cropping a correctly framed 16:9 image to hide bars can remove content without correcting the output shape.
If you change Output Aspect Ratio, make one change and inspect the output again. Confirm that important material still fits: titles, subtitles, devotional lyrics, news tickers and faces near the frame edge can be affected by a different output shape. A correct aspect ratio does not guarantee that every source has safe framing; it only gives you a consistent output shape to evaluate.
For a broader look at planning a pre-recorded channel, see this guide to building a continuous Bengali music channel from videos. It is useful context for playlist operation, but the aspect-ratio diagnosis here still begins in vMix Display settings.
Inspect Output Aspect Ratio
Compare the selected setting with the intended frame before changing anything else. The vMix support article explains the specific 4:3 letterboxing case and identifies Widescreen (16:9) as the setting for a widescreen output. Read the vMix explanation of black bars above and below the output alongside the control in your own version of the software.
A useful test is to use an input whose proportions are familiar, such as a widescreen video with subjects or graphics near both edges. View it through vMix’s output rather than judging only the source preview. If the source itself is 16:9 but the output display is 4:3, the software has to account for the difference in shape; the documented example shows bars above and below. If your symptom is instead missing edges, investigate cropping and framing rather than treating it as the same fault.
Do not assume every combination of source, output, recording and streaming settings behaves identically. The support article describes one cause of a particular symptom, not an exhaustive explanation of all aspect-ratio faults. Record the selected Output Aspect Ratio and the visible result, then move to the master Output Size and streaming encode dimensions. That sequence helps you distinguish a mismatch in the intended vMix output from a later encoding discrepancy.
The Display documentation describes Output Size as the master resolution to which inputs are scaled before Fullscreen, Recording, External Output or Streaming. It is therefore worth checking alongside the aspect-ratio setting. See vMix’s Display documentation for the roles of Output Size and Output Aspect Ratio. A resolution alone does not tell you the whole story: compare its width and height as a pair and ask whether their proportions agree with your intended output.
If you are broadcasting lyrics or subtitles over pre-recorded material, a framing change can affect where that text sits. The guide on displaying Tamil subtitles over pre-recorded video in OBS covers a different broadcast tool, but illustrates why you should inspect overlays and edge placement after any change to the output shape.
Compare encode dimensions
Once you have identified the intended vMix output shape, check the dimensions used for the stream encode. The vMix streaming guide says encode sizes should match the aspect ratio used in vMix. Its examples are 640 x 360 for Widescreen and 640 x 480 for Normal (4:3). These are examples from the cited help26 guide, not a universal recommendation for current YouTube streams or a claim about ideal quality.
Compare the ratio, not just whether the resolution sounds familiar. A 16:9 output and a 4:3 encode describe different shapes. If you select Widescreen in vMix but configure a 4:3 encode, or the reverse, you have a discrepancy to investigate. The available sources support matching encode shape to the vMix selection; they do not verify precisely how YouTube will display every mismatch.
The guide to vMix streaming quality and encode settings is the primary reference for those examples. Treat its resolution values in context, and consult current platform guidance for your actual streaming configuration rather than copying a sample resolution as a default. Resolution, bitrate and aspect ratio answer different questions; increasing bitrate does not itself change the frame shape.
Check the dimensions in the streaming configuration you actually use, not a remembered value from an old preset. If you have multiple profiles, make sure you are inspecting the profile active for this broadcast. Where a setting’s name is unclear, note the numeric width and height and compare them with the Output Size shown in vMix. Avoid changing unrelated quality controls while diagnosing shape; otherwise a better-looking picture may obscure whether you corrected the underlying mismatch.
If the stream dimensions match the intended ratio and vMix output looks correct, but YouTube playback still appears different, preserve those observations. Verify the outgoing encode and refer to current official YouTube guidance before attributing the difference to platform behaviour. The research behind this article did not establish YouTube’s current treatment of mismatched dimensions, so it would be misleading to promise that matching settings always fixes playback.
Check a widescreen source
When only one playlist item looks wrong, inspect that file separately from the rest of the list. Compare its dimensions and framing with a file that appears correctly. One video may have a different aspect ratio, bars already embedded in its picture, or important content close to the edges. In those cases, a correct master output setting can still produce a result that looks different from the other items.
Check the source image itself. Pause on a recognisable frame and look for black bars that are part of the file, not added by vMix. If the bars are in the source, changing the output ratio may not remove them without cropping or otherwise altering the image. If the picture is cropped, check whether the source was already cut off or whether the output shape is trimming its sides. Don’t use a crop as the first response to letterboxing: first establish the intended output shape and where the bars originate.
For a playlist of music videos, bhajans or ambience, compare a few items that have known framing rather than relying on one title card. A title card may use a different canvas from the video that follows it. Likewise, a vertical phone recording mixed into a widescreen playlist may need deliberate framing; changing the whole channel to match that one clip can make every other item look wrong.
Keep a simple note of which inputs are affected, what their source dimensions are, and whether the bars or crop are visible before the stream encode. This is not a special vMix repair procedure; it is a way to avoid confusing a single-file issue with a master output issue. The OBS playlist file troubleshooting guide concerns another system and a different failure, but is relevant if you are also checking whether playlist items are being loaded consistently.
Recheck vMix output
After reviewing Display, Output Size, and encode dimensions, inspect the vMix output again using the same source and the same point in the video. Check the entire frame, not only the centre: a logo, subtitle line or person at the edge can reveal cropping that is easy to miss in a wide landscape scene. If you changed a setting, compare the result with your recorded starting point.
A practical order is: confirm where the defect appears; check Settings > Display > Output Aspect Ratio; inspect master Output Size; compare the stream encode dimensions; then test whether the issue follows one playlist item. The order is deliberate. It begins with the documented vMix letterboxing case, then follows the output path described in vMix documentation, without assuming that YouTube is the cause or that a single setting explains every symptom.
If vMix output now has the intended shape but YouTube playback still does not, avoid repeatedly toggling aspect-ratio settings without new evidence. Confirm which encode profile is active and compare the outgoing dimensions with the intended vMix ratio. Then consult current YouTube Help or creator documentation for the playback question. No source cited here confirms the platform’s current behaviour for every mismatched-dimension scenario.
For a channel that needs to keep running while your own computer is off, a separate operating question is whether to manage the broadcast process yourself or use a cloud-based approach. StreamNeo takes the repeated need to keep a local computer running out of that arrangement: you upload a video, provide your YouTube stream key, and it runs the broadcast while monitoring and restarting it if it drops. It is YouTube-only; aspect ratio still needs to be checked in the video and broadcast settings before you rely on a long run.
If you are comparing approaches for a continuous channel, the article on cloud services for continuous church sermon streaming can help frame the operational choice. It does not replace this vMix diagnosis, and a cloud workflow does not make a wrongly framed source correct. Keep content shape, output shape and the active streaming configuration as separate checks.
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
Why does my vMix stream have black bars?
One documented cause is a widescreen input being shown with bars above and below when vMix Output Aspect Ratio is set to Normal (4:3) instead of Widescreen (16:9). Check Settings > Display > Output Aspect Ratio and confirm that this matches the output you intend to make. Other causes, including bars embedded in the source file, need to be distinguished separately.
How do I set vMix to 16:9?
Open vMix Settings, choose Display, and inspect Output Aspect Ratio. The vMix support explanation identifies Widescreen as 16:9. After selecting the intended shape, inspect Output Size and confirm that the stream encode dimensions use a matching ratio.
What if vMix looks right but YouTube does not?
First verify the active stream encode dimensions and compare them with the intended vMix output ratio. The sources used here do not verify YouTube’s current handling of every dimension mismatch, so do not assume that a platform-side behaviour is the cause. Check current official YouTube guidance before making that attribution.
Should I crop a video to remove the bars?
Not as the first step. Establish whether the bars come from a 4:3 vMix output, are already part of the source file, or occur only later in playback. Cropping can cut off useful material, and it is not the same correction as matching the output and encode aspect ratios.