ffmpeg resize video with same aspect ratio

out_h indicate the height of the output rectangle.out_w indicate the width of the output rectangle.In the definition of crop=out_w:out_h:x:y: We can crop the video using: ffmpeg -i moon_sc_ar.mp4 -vf 'crop=640:in_h:(in_w-out_w)/2:0' moon_sc_ar_crp.mp4 The re-scaled video size from last section is 853 imes480, it is bigger than expected 640\times480. We can set the width or height to -2 (computed value will be even) in order to let ffmpeg resize the video keeping the aspect ratio: ffmpeg -i moon.mp4 -vf scale=-2:480 moon_sc_ar.mp4

The video has been distorted with another aspect ratio. It can be resized following: ffmpeg -i moon.mp4 -vf scale=640:480,setdar=4:3 moon_sc.mp4 3.1 Scaleįirst, we have a video with original size as 1920 imes1080. Herein, we introduce some common options should do the trick. If the video is wider or too short for presentation, we need ways to resize it. However, let’s compare the result when crf=45: ffmpeg -i field.mp4 -c:v libx264 -crf 45 field_crf45.mp4 Consider 17 or 18 to be visually lossless or nearly so. A lower value leads to higher quality, and a subjectively sane range is 17-28. The range of the crf scale is 0–51, where 0 is lossless, 23 is the default, and 51 is worst quality possible. Note here we set constant rate factor crf as 18. Let’s convert a video with H.264, in ffmpeg it follows: ffmpeg -i field.mp4 -c:v libx264 -crf 18 field_crf18.mp4 For windows user, if one doesn’t have administrator privilege, she/he can just unzip the package and cd the bin folder to run the program.Īfter installation, typing ffmpeg in the terminal, if she/he see the window looks like below, it means the package installed successfully! The first step is to install ffmpeg one can find tutorials for Windows here, and for Mac here. Thus, we only need to re-encode videos using libx264. MPEG-4 AVC) and AAC audio are favored format. Mp4 files encoded with H.264 video (a.k.a.

Actually, Microsoft offered reference about supported format and recommendations. However, it doesn’t mean all of them are equally supported inside.

Power point supports tons of video formats. This article introduces how to prepare power point compatible videos with the powerful ffmpeg.

Ffmpeg resize video with same aspect ratio