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FFmpeg plays files in the order listed in a concat-demuxer playlist; it does not automatically sort a folder alphabetically. To stream clips in filename order, create and inspect a playlist with one file entry per video in the intended order, then pass it to FFmpeg. This guide shows the playlist method, explains when stream copy works, and covers YouTube’s ingest setup.
1. Put the filenames in the order you want played
The concat demuxer reads each listed file one after another. The playlist—not the directory’s enumeration order—sets playback sequence. For alphabetical order, list the filenames alphabetically in the playlist before starting FFmpeg.
Zero-pad numbered filenames so ordinary alphabetical sorting follows the intended numeric sequence. For example, clip-001.mp4, clip-002.mp4, and clip-010.mp4 sort in the desired order. Names such as clip-1.mp4, clip-2.mp4, and clip-10.mp4 may not. Inspect the final playlist rather than relying on an unspecified directory listing.
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2. Create the concat playlist
Make a plain-text file named playlist.txt in the directory containing the clips. Add one file directive per video, in playback order:
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ffconcat version 1.0
file 'clip-001.mp4'
file 'clip-002.mp4'
file 'clip-010.mp4'The ffconcat version 1.0 header is optional. If you include it for automatic format recognition, it must be exactly as shown on the first line, with no leading spaces or byte-order mark. Paths with spaces or special characters need correct quoting or escaping; use explicit paths when the playlist and media files are in different directories.
3. Check whether the clips can be joined without re-encoding
Direct stream copy is conditional, not a general fix for mismatched files. The concat demuxer expects the files to have the same streams, including codecs and time bases. Different stream lengths can produce gaps, and inaccurate duration metadata—for example, in a truncated file—can create artifacts. FFmpeg’s concat demuxer documentation describes these constraints and the optional duration directive for overriding a file’s stored duration.
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| Approach | When it fits | Trade-off |
|---|---|---|
Stream copy (-c copy) |
The inputs meet the concat compatibility requirements. | Avoids re-encoding, but does not reconcile incompatible streams, codecs, or time bases. |
| Transcode to a consistent profile | The clips differ and need consistent output video and audio streams. | Requires encoding; select settings for the actual source files and target output rather than assuming one command fits all. |
If stream layouts differ, output stream mapping may also matter. FFmpeg’s stream-mapping documentation explains how mapping controls which input streams are sent and the resulting output stream order. Do not assume a copy command maps every clip correctly.
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This is a command pattern, not a guaranteed command for every FFmpeg build, input set, or YouTube destination. Replace the destination with the server URL and stream key for the intended stream, and confirm that the output protocol, format, and encoding options match your setup.
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ffmpeg -re -f concat -safe 0 -i playlist.txt -c copy -f flv 'YOUTUBE_INGEST_URL/YOUR_STREAM_KEY'- Prepare the playlist. Save
playlist.txtwith its entries in the exact order you want played. - Open YouTube Live Control Room. Get the stream URL and stream key for the intended stream. YouTube’s encoder setup instructions say to enter these values in the encoder. Treat the key like a password and do not share it.
- Set the FFmpeg destination. Replace the example destination with the URL and key supplied for your stream. Keep the key private, including when saving or sharing command logs.
- Check the output settings. The example uses FLV and stream copy; confirm these are appropriate for your inputs and destination. The
-reoption reads file input at its native rate rather than sending it as fast as possible. - Start FFmpeg and monitor the stream. Confirm that YouTube receives the feed and that clips appear in the expected order.
5. Match YouTube’s current ingest recommendations
YouTube’s live encoder guidance lists RTMP/RTMPS, H.264, H.265 (HEVC), or AV1 video, up to 60 fps, AAC or MP3 audio, and constant bitrate encoding. It recommends a two-second keyframe interval, which should not exceed four seconds. These are recommendations, not a guarantee of stream quality.
YouTube’s bitrate recommendations vary by video codec, resolution, and frame rate; there is no single bitrate that applies to every stream. Check the current table in YouTube’s guidance for the row that matches your chosen output profile. If you use -c copy, your output retains the source streams, so verify that those streams and their settings meet the destination’s requirements. If they do not, transcode to a consistent profile.
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6. Troubleshoot ordering, gaps, and connection problems
- Clips play in the wrong sequence: The playlist order controls playback. Reorder the
filelines, check for missing entries, and use zero-padded names if you sort numbered filenames alphabetically. - FFmpeg does not recognize the ffconcat header: If using the optional header for automatic recognition, make it the exact first line, without leading spaces or a byte-order mark. Otherwise, keep the explicit
-f concatinput option. - A filename with spaces or special characters fails: Correctly quote or escape the path in its
filedirective, and confirm the path is valid relative to the playlist or use an explicit path. - FFmpeg reports stream or codec errors: The inputs may not have matching streams, codecs, or time bases. Stream copy cannot make incompatible clips compatible; transcode them to consistent streams and check mapping.
- There are gaps or artifacts between clips: Check stream lengths and duration metadata, especially for truncated files. The concat demuxer supports a
durationdirective to override stored duration when needed. - YouTube does not receive the feed: Confirm that you used the URL and key from the intended Live Control Room stream, and verify the destination format and protocol for your setup. Protect the key if you need to replace or share command text.
- The stream does not meet ingest expectations: Recheck the current YouTube recommendations for your codec, resolution, and frame rate, including constant bitrate and the recommended keyframe interval.
7. Keep a YouTube stream running without leaving a computer on
Running FFmpeg yourself means the machine running it and its connection must remain available for the stream. For uploaded videos that need to loop continuously, StreamNeo is a cloud option: upload your recording or build a playlist, add your YouTube stream key once, and go live. It plays uploaded videos to YouTube; it does not stream from a camera.
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