Time Overlay guide
How to convert a PNG sequence to ProRes 4444 with alpha (ffmpeg)
To convert a Time Overlay PNG sequence to ProRes 4444 with alpha, run the bundled conversion script or a one-line ffmpeg command - both keep the alpha and color quality in a single file editors prefer. The PNG sequence export already ships with that script for macOS, Linux, and Windows.
Recommended Time Overlay export: PNG sequence export, then convert with ffmpeg.
- By
- yansoul
- Published
- Reviewed
Workflow map
Turn lossless frames into one alpha master
Node 01
Inspect frames
Node 02
Run FFmpeg
Node 03
Verify alpha MOV
What was verified for this guide
The conversion path uses the FFmpeg prores_ks encoder with a 4444 profile and an alpha-capable pixel format. A generated MOV must still be inspected with ffprobe and in the target editor before delivery.
- The command uses FFmpeg's prores_ks encoder and the 4444 profile rather than a delivery codec that discards alpha.
- The input frame rate must match the Time Overlay export or the resulting duration will be wrong.
- Verification requires both technical inspection and a visible composite over a non-black background.
Step 01
Install ffmpeg
macOS: `brew install ffmpeg`. Windows: download from ffmpeg.org and add the bin folder to PATH. Linux: `sudo apt install ffmpeg` or your package manager equivalent.
Step 02
Download the Time Overlay PNG sequence
Export 'PNG Sequence' from the Time Overlay generator. The downloaded zip includes the frames plus `convert-to-prores.sh`, `convert-to-prores.bat`, and a README.
Step 03
Run the bundled script
Unzip the archive. On macOS or Linux, run `./convert-to-prores.sh` from a terminal. On Windows, double-click `convert-to-prores.bat`. The script writes `output.mov` next to the frames.
Step 04
Manual one-liner if you prefer
Run `ffmpeg -framerate 30 -i frame-%04d.png -c:v prores_ks -profile:v 4444 -pix_fmt yuva444p10le output.mov` from inside the frames folder.
FFmpeg troubleshooting
Case 01
Symptom
FFmpeg reports that no input files were found
Resolution
Run the command inside the extracted frame directory and make the input pattern match the actual zero-padded filenames exactly.
Case 02
Symptom
The MOV duration is incorrect
Resolution
Set -framerate to the FPS used during export. A 30 FPS sequence interpreted at 24 FPS will play longer than intended.
Case 03
Symptom
The output has no alpha channel
Resolution
Confirm the source PNGs contain RGBA pixels, use profile 4444 with yuva444p10le, then inspect pix_fmt and alpha behavior before deleting the source frames.
First-party references
The encoder and command-line behavior come from FFmpeg; Apple's ProRes description explains why 4444 is used for alpha-bearing masters.
Time Overlay tips
ProRes 4444 alpha is large but lossless. Use it as a master, then transcode for delivery if file size matters. Premiere, DaVinci, and Final Cut all import this file as transparent media without further setup.
Not sure which export format to pick? Compare every transparent overlay format by editor and browser support.
Use the master in an editor
Related guide
How to add a transparent countdown timer in Final Cut Pro
Add a transparent countdown timer to Final Cut Pro by converting a Time Overlay PNG sequence to a ProRes 4444 alpha master and connecting it above the storyline.
Related guide
How to add a transparent countdown timer in Premiere Pro
Add a transparent countdown timer to Adobe Premiere Pro with a numbered Time Overlay PNG sequence, plus an optional ProRes 4444 single-file master.