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Use FFmpeg’s drawtext video filter to burn a clock into the frames sent to YouTube. Choose localtime to display the FFmpeg host’s local time or gmtime for UTC, then set the font, position and contrast. The overlay is part of the outgoing video, so the video must be filtered and encoded rather than copied unchanged.
Choose what time viewers should see
- Host local time: Use
localtimewhen the display should follow the timezone configured on the computer or server running FFmpeg. - UTC: Use
gmtimewhen viewers should see Coordinated Universal Time regardless of the host’s local timezone.
These are wall-clock readings, not elapsed time or a timestamp derived from the media. The filter relies on the host’s clock; it does not synchronize that clock or verify the timezone. Check both settings on the machine that will run the continuous stream.
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Add the clock with drawtext
A schematic filter for a date-and-time clock is:
drawtext=fontfile=/path/to/font.ttf:text='%{localtime:%Y-%m-%d %H\:%M\:%S}':x=20:y=20:fontsize=32:fontcolor=white:box=1:[email protected]This example uses local time, places the text near the upper-left corner, and puts a translucent dark box behind it. Replace /path/to/font.ttf with a font file that exists and is readable by the FFmpeg process. To show UTC instead, use the gmtime expansion in place of localtime.
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The sample illustrates syntax; it is not a complete streaming command or a tested command for every shell. FFmpeg filter arguments can require multiple layers of escaping, and the colons in the clock format are a common source of errors. Test the exact filter in the shell and command-building method you intend to use. FFmpeg’s drawtext reference documents the filter and its clock expansions; its filtergraph syntax documentation explains how filtergraphs are assembled. Using a text file for the overlay text can avoid some escaping difficulties.
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Put the filter in the video path
For a simple video filter, integrate the value with -vf. For a more complex graph, use -filter_complex. Preserve or explicitly map the audio stream as required by your existing command. The input, output protocol, codecs, frame rate, bitrate and YouTube ingest settings depend on your setup; this clock example does not prescribe them.
Check FFmpeg and the font before relying on the stream
The documented drawtext filter uses libfreetype. The FFmpeg filter reference lists --enable-libfreetype and --enable-libharfbuzz as build requirements. A font file can be selected with fontfile; using font names and fallback depends on additional fontconfig support. Text shaping depends on fribidi.
Rank #2
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- AC powered with integrated power supply. Batteries may be used as a backup power source to ensure time and alarms are retained in memory for 8 hours (refer to User Manual for details)
- Measures 4.5 x 3.5 x 2.4 inches (LxWxH); weighs 0.4 pounds (6.6 oz) Note: Batteries are not included
Before deploying, confirm that the actual FFmpeg executable has the filter and required libraries, and that the process account can read the font at the configured path. FFmpeg’s online documentation is regenerated nightly and may differ from an older or specially built local version; consult the documentation for your installed build as well as the FFmpeg release documentation.
Make the clock readable and stable for a 24/7 stream
- Choose a font size appropriate to the outgoing resolution; the example’s size is not a universal recommendation.
- Use high-contrast text and a background box or border if the picture behind the clock changes. The filter supports positioning, size, color, borders, shadows and a box.
- Keep the clock within the visible safe area rather than at the extreme edge.
- Use a stable font path accessible to the account that runs FFmpeg. If the host is moved or reconfigured,
localtimemay show a different timezone. UTC avoids dependence on the local timezone setting, but still depends on the host clock being correct. - Because the overlay is rendered into the outgoing frames, the video has to be filtered and encoded; it cannot be passed through as an unchanged encoded video stream.
Troubleshoot common clock-overlay problems
FFmpeg reports that drawtext is unavailable
The executable may have been built without the needed support or may differ from the online documentation. Verify the installed build’s filter support and its FreeType and HarfBuzz configuration; use a build with the required libraries if necessary.
Rank #3
- Atomic Clock Digital - The clock has a built-in receiver that automatically synchronizes itself with WWVB radio broadcast, which will set and update time automatically every midnight, no need to set manually. It has four time zones selectable: EST, PST, MST, CST.
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- Digital Wall Clock Large Display - The LCD screen measures 6.2 in x 3.7 in and it displays time, indoor temperature, day and date. Each section is showed separately, allows you to read the content easily and quickly.
- Atomic Clock with Auto DST - With DST on, the time would go forward or backward one hour automatically in daylight saving time, no worry about time changing on that day. If for no need, it could also be turned off, then “AUTO DST” disappears from screen.
- Digital Alarm Clock - The alarm could be turned on or off according to your need, just click the button to set. When alarm is set on, there is a bell icon staying on screen. The icon will disappear if alarm is set off. When alarm goes off, just click any button to stop it on the day.
The command fails near a colon or percent sign
Filtergraph, shell and command-construction escaping rules can each apply. Test the filter in the exact environment used for the stream, paying particular attention to the clock-format colons. Consider supplying text through a file to reduce escaping complexity.
The font is missing or the text does not render
Check that the fontfile path is valid on the streaming host and readable by the FFmpeg process account. A path on your desktop will not necessarily exist on a server.
Rank #4
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- Adjustable Alarm Sound: Single alarm setting with 9 minutes snooze. The beep alarm sound can be set from 30-90 DP as preference. Needless worry about too loud alarm sound frightening you or too low to wake you up from deep sleeping. One simple ON/OFF button allows you disable the alarm on weekend.
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- Adapter Powered Only and Battery for Memory: Plug in to power the clock with the included DC adapter (with 59 inches USB cord). 2 x AAA batteries (not included) needed for storing time and alarm settings in case of power outage. With battery power source only, the screen will go blank and alarm will not sound.
The displayed hour is wrong
Confirm whether you selected localtime or gmtime, then verify the host’s timezone and system clock. The filter does not set either one.
The clock is hard to read or is cut off
Adjust the filter’s position, font size and color, and enable a box or border for contrast. Check the result at the actual output resolution and ensure the text is inside the visible frame.
Best Value
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The stream stops after adding the filter
The filter changes the video path, so the existing command must encode the filtered frames rather than stream-copying the original video. Check the command’s video mapping and encoding settings while preserving the audio mapping. Choose ingest and encoder settings for your configuration and verify current requirements in YouTube’s live encoder guidance; this article does not prescribe numeric bitrate values.
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