Uploading video, explained
Getting a multi-gigabyte file from a laptop to a server, over a connection built for downloading, is harder than it looks. This hub explains how it works, how it fails and how to fix it.
To upload video reliably, send the file in chunks over a resumable protocol. Then a dropped connection costs seconds, not the whole transfer. Prepare the file so it is accepted first time. And check your upload speed, not your download speed, because that is what sets the clock.
Guides in this hub
- How-toHow to upload 2 GB video filesLarge uploads fail for boring reasons: a sleeping laptop, a flaky Wi-Fi hop, a file that was never going to be accepted. Here is how to get a big file up in one go, and what to do when it stops.8 min readRead
- ExplainerResumable uploads explainedA resumable upload is a conversation, not a single request. The client sends pieces and the server keeps count. After a break, they agree on where to continue. This is how the tus protocol does it.8 min readRead
- TroubleshootingWhy video uploads failAn upload that stops, stalls, restarts or is rejected is almost always one of a short list of causes. Learn to tell them apart from what the browser shows you, and fix the right one.8 min readRead
- How-toPrepare video for uploadThe right export is smaller, uploads faster, is accepted without complaint and transcodes cleanly. It is not the highest possible quality and it is not the smallest file. Here is the middle.8 min readRead
- ExplainerVideo upload speed and timeUpload time is file size divided by upload speed, and upload speed is the number nobody checks. Here are the sums, a reference table and the few changes that really help.8 min readRead
Almost every home and office connection is lopsided. The upload speed is a fraction of the download speed, sometimes a tenth. A file that downloads in three minutes can take half an hour to send. For all of that half hour, the connection has to hold.
Add a browser tab that gets closed, a laptop that goes to sleep and an office proxy with its own rules about long requests. It is no surprise that upload is where most people first meet a real failure. This hub covers the whole journey, from a file on disk to a source safely stored on the server. It explains how the pieces fit and which guide to read for the problem in front of you.
Why a plain form upload is not enough
The classic HTML file input sends the whole file as one HTTP request. That works for a photo. For a 2 GB video it is fragile, for two reasons.
One request, one point of failure
If anything breaks the connection, the server has nothing usable. The browser starts again from byte zero. There is no way to ask the server how far it got.
Size limits along the way
Many servers cap the size of a single request. A large file may be refused with a 413 response before a byte of video is stored. Why video uploads fail lists these failures and what each one looks like in the browser.
Resumable uploads: chunks and offsets
The fix is to send the file in pieces and let the server keep count. VideoBB uses tus, an open protocol built on ordinary HTTP. Resumable uploads explained goes through it request by request.
How tus keeps count
The client first creates an upload. It then sends chunks with PATCH requests, and each one states where it starts. After a break, the client asks the server with a HEAD request how many bytes it holds. Then it carries on from there, so nothing is sent twice.
On VideoBB you can resume within 48 hours in the same browser. The help page on resuming an interrupted upload shows the steps.
Why memory use stays flat
The browser reads the file in slices with the standard Blob.slice method. So a multi-gigabyte file never has to be loaded into memory at once.
The uploading guides
Which guide answers which question.
| If you want to know | Read |
|---|---|
| How to get a 2 GB file uploaded without it failing | How to upload 2 GB video files |
| What the browser and server are actually doing | Resumable uploads explained |
| Why an upload stopped, stalled or was rejected | Why video uploads fail |
| What settings to export with before uploading | Prepare video for upload |
| How long an upload will take on your connection | Video upload speed and time |
The file matters as much as the connection
Many failed uploads are not network failures at all. The file may be in a container the host does not accept. It may be over the size limit. Or it may not be a video at all: a project file, a zipped folder or a file with a renamed extension.
What VideoBB accepts
VideoBB accepts mp4, mkv, avi, mov, webm, m4v, mpg, wmv, flv, ts and 3gp, up to 4 GB each. It checks, or probes, each file before processing. The help page on supported formats and size limits keeps the current list, including how many uploads you can make each day.
Export settings that pass first time
Export H.264 video with AAC audio in an mp4, at a bitrate that suits the resolution. The file is then smaller, uploads faster and is accepted first time. Prepare video for upload has the settings. The video formats hub explains why the extension alone tells you little about what is inside.
Time: it is the upload speed that counts
How long an upload takes is the file size divided by the upload speed. Most people have never checked their upload speed. Video upload speed and time gives a table for common speeds and sizes, and the ways to shorten the wait that actually work.
The arithmetic
A 2 GB file on a 10 Mbps upstream takes about 27 minutes, if nothing else is using the connection. The sum is 2,000 megabytes times 8 bits, divided by 10 megabits per second. Wi-Fi, other devices, a VPN and the server's own intake rate all add to that figure.
Making the file smaller
A smaller file is the one fix that always helps. The free video compressor can shrink a file to a target size. The trim tool cuts dead air from the start and end. How to upload 2 GB video files covers the rest of the set-up for a big upload.
Related reading in other hubs
Uploading touches formats and quality; these guides pick up the threads.
Why the file extension tells you little about what is inside, and what ffprobe reveals.
FormatsVideo bitrate guideThe bitrate that keeps an export small without making every rendition soft.
QualityVideo transcoding explainedWhat the host does with the file the moment the last chunk lands.
StreamingFrequently asked questions
What is the largest video I can upload?
VideoBB accepts files up to 4 GB each. That is enough for well over an hour of 1080p at typical export bitrates. If a file is over the limit, re-export at a slightly lower bitrate rather than a lower resolution. Or split a long recording at a natural break. Most editors show the estimated file size before export.
If my connection drops, do I start again?
No. Uploads use the tus resumable protocol. The browser asks the server how much it already has and continues from that byte. You lose at most the chunk that was in flight. Keep the tab open and the laptop awake if you can. If not, return to the upload page within 48 hours in the same browser to resume.
Why is uploading so much slower than downloading?
Most home and office connections are lopsided: the upload direction gets a fraction of the download speed. A connection sold as 100 Mbps may upload at 10 or 20 Mbps. Run a speed test and read the upload figure. That is the number that sets how long a video takes to send.
Sources
- tus resumable upload protocol — The protocol behind chunked, resumable uploads.
- MDN: Blob.slice() — How browsers read a file in chunks without loading it into memory.
- MDN: 413 Content Too Large — The response a server sends when a single request is too big.
- FFmpeg documentation — Preparing and inspecting files before upload.