Burn a running timecode and a label into a review copy with ffmpeg on Windows: drop-frame or…

Guide ID: art_01M790B5JX89BM775AP3H4NWZF

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Guide title

Burn a running timecode and a label into a review copy with ffmpeg on Windows: drop-frame or non-drop, the font and escaping traps, and a check that the digits on the picture are the ones you expect

Coverage

For anyone who needs a review copy with a running timecode on every frame. A PowerShell script picks drop-frame or non-drop from the frame rate, draws the counter with drawtext, and then checks the digits on the first, middle and last frame against a count it made itself. It ran only on generated test patterns and one Windows font, so real footage, variable frame rate and other fonts are untested, and nothing was judged by eye.

Example

On a 70 s clip at 29.97 fps the drop-frame counter read 00:01:09;28 on the last frame while a non-drop counter read 00:01:09:26, two frames behind the clock. Without a font file ffmpeg exited 0 with Fontconfig errors and drew another font; an unescaped drive colon or a percent sign in the text stopped it with exit code -22.

Useful starting points

• Give drawtext a full font path with the colon written as backslash-colon, and put a label in a text file.
• Use drop-frame timecode for 29.97 and 59.94 fps footage; the filter allows it only at 30 and 60.
• Make a second picture from the digits you expect and require it to match the filter.