Manatee

A video a website rejects even though it is under the size limit

· 6 min read

When a 40 MB video bounces off a form that allows 100 MB, size is not the problem. Upload systems also look at what is inside the file: the video codec (HEVC where only H.264 is accepted is a frequent culprit), the container (MOV where only MP4 is listed), the audio format, the resolution, the length, and whether the file reads cleanly from start to finish. You can check all of that on a Mac in a couple of minutes, then make an H.264 MP4 copy that fits what the site asks for.

Why a file under the limit still fails

An upload is usually checked twice. First in your browser, against the extension and the file type the browser reports. Then on the site’s servers, where the video is opened and processed, often converted for streaming. Either step can refuse it, and the messages are vague: “unsupported format”, “invalid file”, “upload failed”, or a processing bar that never finishes.

The usual causes:

  • HEVC video. iPhones record HEVC (H.265) by default. Many big platforms accept it, but form-based upload systems, learning platforms, job and visa portals and older content systems often take only H.264. H.264 vs HEVC covers who supports which.
  • MOV instead of MP4. QuickTime Player, screen recordings and iPhone exports produce .mov files. A form that lists MP4 may check only the extension, or the type the browser reports for a .mov, and refuse even when the video inside is H.264. Container vs codec explains why the name and the contents are separate questions.
  • The audio track. Strict systems usually expect AAC audio. Uncompressed PCM (common from cameras and some recorders), AC-3 surround or Opus can fail processing even when the picture is fine.
  • Resolution, frame rate or duration caps. A second set of limits often hides in the help page: 1080p maximum, 30 frames per second maximum, two minutes maximum. A short 4K clip at 60 frames per second can be well under the size cap and still break the resolution and frame-rate limits.
  • Variable frame rate. Phones and screen recorders vary the frame rate as they go. Most sites cope. The ones that do not usually say “constant frame rate” somewhere in their requirements.
  • HDR. Recent iPhones record HDR video by default. Some upload processors reject it, and others accept it and make it look gray and washed out.
  • A damaged file. A recording cut short or a copy interrupted partway can still play on your Mac, because QuickTime is forgiving, and then fail when a server tries to read it from start to finish.
  • A file that is not what its name says. A WebM renamed to .mp4 gets past the browser’s extension check and fails at processing.

Check the video on your Mac

You can read almost everything a site checks without extra software.

  1. Finder. Select the video, press Command-I and expand More Info. The Codecs line reads something like “HEVC, MPEG-4 AAC” or “H.264, MPEG-4 AAC”, and Dimensions and Duration are listed with it. A MOV or MP4 with no Codecs line at all is a warning sign: either it is not really that format, or macOS could not read its header.
  2. QuickTime Player. Open the video and choose Window > Show Movie Inspector (Command-I). It shows the format of each track, the encoded frame rate, the data rate and the native size.
  3. Terminal. Recent versions of macOS include avmediainfo, which prints one line per track with the format, dimensions, frame rate and duration:
avmediainfo ~/Desktop/IMG_4410.MOV --brief

If it answers “Failed to load asset”, macOS cannot read the file’s structure, which points to damage or a disguised format. To unmask a disguised one, file ~/Desktop/clip.mp4 names what the file actually is; in our testing a renamed WebM came back as “WebM” whatever its extension said. A clean result from avmediainfo is not proof the whole file is intact, though. In our testing it read a file cut off at 60 percent without complaint, because its index sat at the front, so play the video through to the end as well.

Then put what you found next to the site’s list: codec, container, audio, maximum resolution, frame rate and duration. Most rejections become obvious at this point.

Make a copy the site will take

For most of these causes the answer is the same: H.264 video with AAC audio in an MP4. Do any trimming or resizing first, so the conversion works on the final version.

  1. Trim for a duration cap. In QuickTime Player, choose Edit > Trim (Command-T), drag the yellow handles, and click Trim.
  2. Resize for a resolution cap. Choose File > Export As and pick 1080p or 720p. If QuickTime offers a choice between greater compatibility and smaller file size, greater compatibility is H.264. The result is a MOV.
  3. Convert to MP4. In Manatee, choose Convert, drop the video into the window or onto the menu bar icon, and pick MP4. The new file is written next to the original, which is never changed, and nothing leaves your Mac. Manatee is free for 24 hours with every feature.
  4. Check before uploading. Look at the new file’s Codecs line in Get Info, or run avmediainfo on it, so you know you are sending H.264 and AAC rather than hoping.
  5. Shrink if the copy is now too big. An H.264 version of an HEVC clip is often larger. Manatee’s Shrink mode takes a size in MB and finds the quality that fits; type a little under the limit to leave margin. For videos on a page you build yourself, how to compress a video for a website covers sizing and fast start.

If the site caps the frame rate or insists on a constant one, check the frame rate of the result in QuickTime’s Movie Inspector before you upload. If the copy is over the cap, or the site still rejects it, export from a video editor set to a fixed rate the site accepts.

When the file itself is the problem

If avmediainfo cannot load the video, Finder shows no Codecs or Duration for a MOV or MP4, or the clip freezes or stops early in QuickTime, deal with the damage before anything else. Converting a damaged file usually carries the damage into the copy. Manatee’s Repair mode rebuilds a video’s index and reports Fixed, Partial (for example, the first eleven minutes of a nineteen-minute recording) or Not fixable; repair first, then convert the repaired copy. A fresh copy from the phone or the original download is better than any repair, so check for one before you start.

Questions

The site accepts MP4. Can I just rename my .mov to .mp4? Sometimes that gets past the browser check, since MOV and MP4 are close relatives, and then the upload fails at processing if the codecs are not ones the site takes. A proper conversion takes a few minutes and removes the guesswork.

Why does the upload reach 100 percent and then fail? The transfer worked and the processing did not. That points to what is inside the file, such as the codec, audio, HDR, frame rate or damage, rather than its size or your connection.

Should I set my iPhone to record H.264 instead? Only if most of what you film goes straight into systems like this. Settings > Camera > Formats > Most Compatible records H.264 and JPEG, at noticeably larger file sizes, and gives up some recording modes that need HEVC. Converting the occasional clip is usually the better trade.