For a local FFmpeg concat playlist, put each filename in quotes inside the playlist text file—not just in the shell command. For example, write file 'video one.mp4'. If FFmpeg then rejects the entry as unsafe, add -safe 0 for a list you trust. If you are passing one file directly with -i, quote the path in your shell instead; that is a separate parsing layer.
First identify which kind of playlist you have
“YouTube playlist” can mean downloaded videos whose filenames came from a YouTube playlist, or a YouTube URL being passed to a tool. The instructions below cover local files read by FFmpeg. A YouTube URL is a separate workflow: yt-dlp can download videos, after which FFmpeg can read the resulting local paths. The available documentation does not establish support for every YouTube URL or playlist form directly in FFmpeg.
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For a local concat-demuxer list, the list file has its own syntax. Quoting the list file in the command does not quote the filenames written inside it.
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsQuote filenames inside the concat list
Create a text file such as files.txt with one entry per video. Enclose each path with spaces in single quotes:
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ffconcat version 1.0
file 'video one.mp4'
file 'video two.mp4'FFmpeg’s concat demuxer documentation says that spaces and special characters in a path must be escaped with backslashes or enclosed in single quotes: FFmpeg concat demuxer documentation. Paths are interpreted relative to the list file when given as relative paths; use the correct path for where your files are stored.
For a trusted list that FFmpeg rejects because of its safe-path check, use:
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ffmpeg -f concat -safe 0 -i files.txt -c copy output.mp4The concat demuxer defaults to safe=1, which permits only a restricted set of portable path characters; spaces are not in that set. -safe 0 relaxes this check. Use it only with a list you control, not an untrusted list file. The command is a pattern, not a guarantee that any particular pair of files will concatenate correctly.
If you are passing a single filename directly
When FFmpeg reads one file directly, quote the whole path as a single shell argument. For example, in Bash:
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ffmpeg -i "video one.mp4" output.mp4Shell quoting differs across Bash, PowerShell, Windows Command Prompt, and other environments. The shell removes its quoting before FFmpeg receives the argument, and embedding FFmpeg syntax in another shell command or script can require another escaping layer. See FFmpeg’s quoting and escaping documentation and adapt the example to your shell.
Diagnose the error at the layer that parses the path
- The reported path stops at the first space: the filename is likely being split at the shell or list-file layer. Quote the direct
-ipath in the shell, or quote thefileentry inside the concat list, depending on how you supplied it. - The error says the filename or path is unsafe: if the concat list is yours and trusted, retry with
-safe 0. This addresses validation, not malformed quoting. - FFmpeg cannot open the file: verify the spelling and path relative to the concat list, and check that the file exists and is accessible.
- You have a YouTube URL rather than downloaded files: handle downloading separately, for example with yt-dlp, then give FFmpeg the resulting local paths. Do not assume concat-list syntax applies to a URL.
Optional: avoid spaces when yt-dlp creates filenames
If you prefer filenames without spaces or other special characters, yt-dlp provides --restrict-filenames. This is a naming preference or workaround, not a requirement for FFmpeg: properly quoted filenames with spaces can be read. See the yt-dlp filesystem options.
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Correct filenames do not guarantee a successful stream-copy join
The concat demuxer joins packet streams. For stream-copy concatenation such as -c copy, the input files need matching streams, codecs, and time bases. Correct path quoting only makes the files addressable; it cannot make incompatible media compatible. The demuxer also adjusts timestamps, and inaccurate durations can cause artifacts. If the files differ, inspect their stream properties and consider a workflow that decodes and re-encodes them, such as using a concat filter, rather than assuming stream copy will work. See the concat demuxer requirements.
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