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How do I set frame size in ffmpeg?
This can be done in two ways as discussed above, so let’s try both ways.
- Specify the Width To Retain the Aspect Ratio. ffmpeg -i input.mp4 -vf scale=320:-1 output.mp4. The resulting video will have a resolution of 320×180 .
- Specify the Height To Retain the Aspect Ratio. ffmpeg -i input.mp4 -vf scale=-1:720 output.mp4.
What is scale Ffmpeg?
The scale filter forces the output display aspect ratio to be the same of the input, by changing the output sample aspect ratio. If the input image format is different from the format requested by the next filter, the scale filter will convert the input to the requested format.
How do I crop with FFmpeg?
Crop a Video in FFmpeg with Variables
- Bottom right corner: crop=in_w/2:in_h/2:in_w/2:in_h/2.
- Remove $x pixels from the top and bottom: crop=in_w:in_h-2*$x.
- Remove $x pixels from either side of the video: crop=in_w-2*$x:in_h.
How to set frame size in FFmpeg format?
There are options http://manpages.ubuntu.com/manpages/oneiric/man1/ffmpeg.1.html -s size Set frame size. The format is wxh (ffserver default = 160×128, ffmpeg default = same as source). The following abbreviations are recognized:
How to change frame size, preserving width?
You may want to put additional commands for the codec and so on, eg -c:v libx264 to use the x264 mp4 encoder, and something like -crf 20 to set the constant rate factor to 20 (usually a pretty good compromise between size and quality). So, a reasonably complete command would look like:
What can a FFmpeg video converter do for You?
ffmpeg is a very fast video and audio converter that can also grab from a live audio/video source. It can also convert between arbitrary sample rates and resize video on the fly with a high quality polyphase filter.
How does FFmpeg select stream in out1.mkv?
out1.mkv is a Matroska container file and accepts video, audio and subtitle streams, so ffmpeg will try to select one of each type. For video, it will select stream 0 from B.mp4, which has the highest resolution among all the input video streams. For audio, it will select stream 3 from B.mp4, since it has the greatest number of channels.