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Open toolFFmpeg Command Generator (H.264, H.265, AV1, Trim & Scale)
Construct production-ready, shell-escaped `ffmpeg` commands for H.264 (`libx264`), H.265 (`libx265`), and AV1 (`libsvtav1`) transcoding, even-dimension scaling (`scale=-2:1080`), EBU R128 loudness normalization, and `-movflags +faststart` web streaming.
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Enter the inputs, then select Generate FFmpeg Command.
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How the FFmpeg Command Builder Prevents Common CLI Errors
Hand-written FFmpeg commands often fail in production due to odd scaling dimensions, missing QuickTime pixel formats, incompatible stream-copy filters, or unquoted spaces in filenames.
ffmpeg -hide_banner [-ss START -to END] -i 'INPUT' [-c:v CODEC -preset medium -crf CRF -pix_fmt yuv420p] [-vf 'scale=-2:H'] [-c:a ACODEC] [-movflags +faststart] 'OUTPUT'
Need to batch-discover media files or transfer finished renders over SSH? Pair this tool with our Find Command Generator (/tools/find-command-generator) and Rsync Command Generator (/tools/rsync-command-generator).
FFmpeg Codec, CRF Quality & Filter Flags Reference Table
Essential FFmpeg flags, recommended CRF ranges, and compatibility guardrails included automatically by this generator.
| Task / Codec Layer | FFmpeg Flag Pattern | Recommended Production Setting | Why It Matters |
|---|---|---|---|
| Universal Web MP4 (H.264) | `-c:v libx264 -crf 23 -pix_fmt yuv420p` | `CRF 18–23`, `-preset medium` | `yuv420p` prevents black screens in QuickTime/Safari |
| Apple / Modern HEVC (H.265) | `-c:v libx265 -crf 26 -tag:v hvc1` | `CRF 24–28`, `-tag:v hvc1` | Apple requires `hvc1` fourcc tag (rejects default `hev1`) |
| Aspect-Safe Scaling | `-vf "scale=-2:1080"` | `-2` width auto-calculation | Guarantees width is divisible by 2 for 4:2:0 chroma |
| Web Streaming Start | `-movflags +faststart` | Always enable on `.mp4` / `.mov` | Relocates `moov` atom to byte 0 for instant `<video>` seek |
| Podcast / Video Loudness | `-af "loudnorm=I=-16:TP=-1.5:LRA=11"` | `-16 LUFS` stereo target | Matches YouTube, Spotify, and Apple Podcasts loudness |
How to Build an FFmpeg Command in 3 Steps
Configure your input/output paths, codec quality, and filters in seconds.
Enter your input and output filenames
Type your source path (e.g. 'input.mov') and target path (e.g. 'output.mp4'). Paths with spaces or special characters are POSIX-quoted automatically.
Select your video codec, CRF quality, and resolution scale filter
Pick H.264 (libx264), H.265 (libx265 with -tag:v hvc1), AV1 (libsvtav1), or lossless stream copy (-c:v copy), and adjust CRF between 0 and 51.
Choose audio processing and optional trim timestamps, then copy
Add optional EBU R128 audio normalization or start/end trim timestamps, then copy the single-line or multi-line command.
Worked FFmpeg Command Examples
Compare three real-world media workflows generated by this tool.
Baseline example
Free interactive FFmpeg command generator. Build shell-escaped ffmpeg commands for H.264, H.265/HEVC, AV1, VP9, CRF compression, resolution scaling, trimming, and audio normalization.
Comparison scenario
ffmpeg -hide_banner [-ss START -to END] -i 'INPUT' [-c:v CODEC -preset medium -crf CRF -pix_fmt yuv420p] [-vf 'scale=-2:H'] [-c:a ACODEC] [-movflags +faststart] 'OUTPUT'
Boundary check before exporting
Need to batch-discover media files or transfer finished renders over SSH? Pair this tool with our Find Command Generator (/tools/find-command-generator) and Rsync Command Generator (/tools/rsync-command-generator).
How to Choose Between CRF Values, Codecs, and Presets
Balance encoding speed, browser compatibility, and storage bandwidth.
For H.264 (`libx264`), `CRF 23` is the standard balance; lower it to `CRF 18` for archival master quality or raise it to `CRF 26–28` for mobile messaging previews.
When using H.265 (`libx265`) or AV1 (`libsvtav1`), you can use a numerically higher CRF (`26` to `30`) to achieve the same perceptual sharpness as H.264 at `CRF 23` with 35% to 50% smaller files.
Safety Guardrails & Related Developer CLI Tools
Review these shell and container constraints before running batch scripts.
1. Never Overwrite In-Place: FFmpeg cannot read from and write to the exact same file path simultaneously; always specify a distinct output filename.
2. Container Compatibility: WebM outputs require VP9 (`libvpx-vp9`) or AV1 (`libsvtav1`) video and Opus/Vorbis audio; MP4 supports H.264, H.265, and AV1 with AAC or MP3 audio.
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Open toolFrequently Asked Questions About FFmpeg Commands
Answers about using FFmpeg Command Generator (H.264, H.265, AV1, Trim & Scale) and understanding its results.
Why does the generator use 'scale=-2:1080' instead of 'scale=-1:1080'?
Chroma-subsampled 4:2:0 codecs (H.264, H.265, AV1 with yuv420p) require both width and height to be divisible by 2. Using -1 can produce an odd width (e.g., 1919 px) and crash the encoder with 'width not divisible by 2', whereas -2 tells FFmpeg to preserve aspect ratio and round to the nearest even integer.
What does '-movflags +faststart' do on MP4 files?
By default, FFmpeg writes the MP4 'moov' atom (the index table of frames and timestamps) at the very end of the file after encoding finishes. Adding '-movflags +faststart' performs a quick second pass that moves the moov atom to the front of the file so web browsers can start streaming playback before the full file downloads.
How much does file size change per 6 units of CRF?
In x264 and x265, Constant Rate Factor (CRF) is logarithmic: decreasing CRF by 6 (for example, from 23 to 17) roughly doubles the output bitrate and file size, while increasing CRF by 6 (from 23 to 29) roughly halves the file size.
Can I use '-vf scale' together with '-c:v copy'?
No. Video filters (-vf scale, crop, fps) require decoding and re-encoding uncompressed frames, so they are incompatible with stream copying (-c:v copy). If you select '-c:v copy', this generator automatically omits '-vf' and '-crf' so your remux succeeds.
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