vMix can sequence files in a List input and switch between inputs with PlayList. It does not follow from those normal playback features that a file which fails to open or decode will automatically switch to a backup; test that behaviour on your installed version before relying on it.
The important distinction is between a video reaching its normal end and a video failing before it can play. vMix documents OnCompletion for the first case, with Loop disabled, but the documentation reviewed does not establish that an unreadable file fires the same trigger. Build a fallback path, then deliberately test the error condition.
Choose List for files within one input
Use a List when you want several audio or video files grouped within one vMix input. The vMix Video List documentation describes a List as a playlist of video and audio files. This is useful when the files are part of one continuous programme and you want to manage their order together rather than create a separate input for each clip.
A List also has ordinary playback controls. Auto Next is enabled by default, so playback can move to the next enabled entry during normal sequencing. Loop returns playback to the beginning when it reaches the end. You can disable entries to keep them in the list without playing them, and the interface can export the current list as an M3U file.
These controls describe list organisation and routine progression. They do not, by themselves, document what happens if a file cannot be opened, is missing from its storage location, or fails during decoding. A disabled entry is intentionally excluded; an unreadable entry is an error condition. Do not treat those as equivalent.
For example, a devotional channel might keep a morning sequence of bhajans in one List input. Auto Next can move on when a track completes normally. If one file has been renamed on disk, however, you need to observe how that particular vMix release handles it rather than infer that the next item will play.
Use Auto Next for sequential playback
Auto Next is appropriate when the requirement is “play the next file after this one finishes”. That is a normal end-of-playback rule. It is not a general-purpose instruction to inspect every file in advance, detect all media faults, and recover from them.
Before relying on a List for unattended playback, check its order and confirm that each entry refers to the intended file. Play the whole sequence, including transitions between items, with the same storage paths and media you plan to use on air. If the playlist depends on an external drive or a network location, make the test with that location connected in the same way it will be during the broadcast.
A practical distinction is worth keeping in your notes: “file finished” means vMix played it through to its end; “file failed” means playback did not start or could not continue as intended. A clean Auto Next demonstration proves the first behaviour. It does not prove the second.
If your channel is built around long prerecorded runs, you may also find it useful to review how to stream prerecorded retail product comparison videos on YouTube Live. The useful lesson is to think through the actual order and programme structure, not merely the act of loading files.
Use PlayList to switch between inputs
PlayList works at a different level from List. The vMix PlayList documentation says it can automate switching tasks or play multiple videos sequentially. Rather than holding multiple files in one input, a PlayList sequences inputs and applies transitions between them.
A PlayList item can have its own starting position, duration, transition and transition time. In Manual Mode, the sequence waits for the operator to click Next; Next advances to the following item using that item's transition. PlayLists belong to the active preset, so include the relevant preset in your rehearsal and check that the intended PlayList is present when you load it.
Choose between the two features based on what you need to sequence:
| Requirement | Better fit | What it controls | What it does not prove |
|---|---|---|---|
| Several files played through one input | List | File order, enabled entries and normal playback progression | Recovery from a file-open or decode failure |
| Several distinct inputs switched in order | PlayList | Input sequence, duration and transition choices | That an error in one input automatically advances to another |
| Operator-controlled progression | PlayList Manual Mode | When the operator issues Next | Automatic detection of a failed file |
This distinction matters when you design a backup. A separate input containing known-good material gives the operator a distinct source to select, and a PlayList can sequence that input as part of a normal plan. Neither fact establishes that vMix will select it automatically when the primary file fails. Treat “backup is prepared” and “backup is triggered by an error” as separate claims.
For a continuous channel, it can help to map the sequence before building it: identify the primary input, the known-good fallback input, the transition you intend to use, and who can take control if the primary behaves unexpectedly. Readers comparing approaches for a small operation may also consult automated YouTube playout software for a small channel; the central question remains whether the workflow covers the particular failure you are trying to handle.
Understand what OnCompletion means
OnCompletion is a trigger, not a general media-health alarm. The vMix Triggers documentation describes it as applying to video, List, photos and PowerPoint inputs when they reach the end, assuming Loop is not enabled. In other words, its documented condition is completion at the end of playback.
That gives you a useful building block for a planned sequence. If a video reaches its end and Loop is off, you can configure an OnCompletion action and verify the expected action in a controlled test. If Loop is on, the input does not reach the end in the same way, so the trigger condition described in the documentation does not apply as written.
The documentation reviewed does not say that an input which cannot open a file, or one whose decoder encounters a problem, counts as having reached the end. Do not wire an OnCompletion action to a backup and assume it will catch those cases. It may behave differently in your setup, but that is a result to establish through testing, not a documented guarantee.
Triggers also have practical scope limits. The trigger guide limits trigger delay to 30 seconds and recommends PlayList or Scripting for long-running operations. This is another reason to design the normal sequence using the feature intended for it, and to avoid stretching a completion trigger into an unverified failure detector.
When testing OnCompletion, first use a file that plays normally, disable Loop, and observe whether the action occurs at its end. Record that as the normal completion result. Then run a separate failed-file test; do not combine both observations into one conclusion.
Prepare a separate fallback input
Keep the backup material distinct from the primary path. A separate input with known-good content makes the fallback visible and selectable, even if the particular failure does not result in an automatic switch. Give inputs clear names, such as “Primary sequence” and “Fallback loop”, so an operator can tell what is live without interpreting a row of similarly named clips under pressure.
Decide what the fallback is meant to do. It might hold a single tested video, or it might be a separate sequence of files. Set its intended starting point and transition, then check that the input can play cleanly in the active preset. If you use PlayList for normal switching, include the fallback as an item only if that is how you want the routine sequence to work; having it in a PlayList does not on its own create error-based failover.
Keep an operator path available when the channel matters overnight. Rehearse the manual action needed to take the fallback, including how to identify the current input and what transition will be used. In Manual Mode, Next is an operator command for moving through the PlayList; it is not an automatic recovery signal. A person able to switch inputs may be a more honest part of the plan than an unverified trigger.
A 24/7 channel has more than one kind of continuity problem. A planned sequence can loop or advance normally, while a missing file, unavailable drive, or an application issue calls for a different response. The vMix knowledge base notes that List and PlayList provide basic ways to play videos consecutively and loop them, and separately says vMix does not provide time-of-day scheduling for 24/7 television programming. A loop is useful, but it should not be described as comprehensive unattended recovery.
If the broader goal is a prerecorded YouTube channel that can keep running while your computer is off, StreamNeo removes the specific burden of keeping a local playback computer running, but it does not change the need to prepare valid media and verify the failure behaviour of the playout arrangement you choose.
Test failed and unreadable media on the exact setup
Treat the failure test as its own acceptance check. Use a safe rehearsal preset or test copy, not the live programme. Record the vMix version, the media location, the file used, the relevant List or PlayList settings, and what you observed. The result applies to that combination; it is not automatically transferable to another release, storage location, or file type.
Test distinct failure cases separately. A file that is absent at the expected path may behave differently from a file that exists but cannot be decoded. A drive that becomes unavailable may differ from both. For a controlled test, you could remove access to a test copy or use a deliberately invalid test file, then observe whether vMix stops, advances, displays an error, or invokes a trigger. Restore the test environment afterwards and confirm the normal sequence still works.
For each case, ask concrete questions: Did the primary input continue? Did it move to another List entry? Did a PlayList item advance? Did OnCompletion run? Was there an observable state change or error that an operator or automation could use? Avoid writing “failover works” unless you observed the intended switch repeatedly in the actual arrangement you plan to use.
The Web API can execute shortcut functions and expose vMix state, and Web Scripting can run a sequence of API-style functions with pauses. Those are control tools, not proof of a media-failure detector. The vMix Developer API reference documents HTTP 500 responses for API errors, but the reviewed documentation does not establish that a failed video open or decode produces a specific API error, state change, or event suitable for switching to a backup. A failed API request is not the same claim as a failed media file being detected.
If you need custom automation, first identify a signal that actually distinguishes the failure you care about on your setup. Confirm that an external monitor or script can see it, and test the switch command independently. Only then connect detection to switching. If no reliable signal is confirmed, keep a human operator path or redesign the programme so a known-good fallback can be selected without claiming automatic recovery.
For a channel whose main risk is a playback gap between files rather than a failed file, the practical checks differ. How to stop a 24/7 YouTube radio stream from going silent between playlist files is relevant to the transition and sequencing side, while this guide’s failure test concerns whether the next source is selected after an error.
Make the decision before going live
Write down the behaviour you have demonstrated and the behaviour you have not. For example: “A normally completed clip advances through the List with Auto Next” is a direct observation. “A missing file advances to the fallback” should only appear in your runbook if you reproduced that exact condition and saw the switch on the installed version and storage arrangement.
If the test does not switch automatically, that is useful information, not a failed setup exercise. You can choose to keep an operator ready, simplify the primary sequence, use a separate known-good input, or seek clarification from vMix support about the current release. Do not make a critical overnight workflow depend on a trigger behaviour that you have not verified.
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FAQ
Can vMix skip a video it cannot play?
The documented List controls include normal progression and skipping disabled entries, but the sources reviewed do not establish that an unreadable or failed file is automatically skipped. Test the exact file and setup, and keep a manual route to known-good content until you have verified the result.
Does OnCompletion run if a file fails to load?
The documented condition is that a video or List input reaches the end with Loop disabled. The documentation reviewed does not say that failure to open or decode a file counts as completion, so do not depend on that trigger for this case without a controlled test.
Should I use List or PlayList for a backup?
Use List when you are grouping files within one input, and PlayList when you are sequencing or switching between inputs. A separate fallback input can make the backup easier to select, but neither arrangement proves automatic switching after a file error.
Can the vMix API detect a failed video and switch inputs?
The API and Web Scripting documentation describe controls and state access, but the reviewed material does not establish a specific media-failure signal. Verify a signal for your particular failure before using it to drive a switch; otherwise, plan for manual intervention.