![]() video recorded by your iPhone, iPad, Panasonic GH5, etc.These huge recording benefits make VFR shooting adopted in many places. As the name suggests, if a video is recorded in VFR mode, the camera will automatically adjust the frame rate according to what's going on in the scene.Ĭompared to CFR(constant frame rate), this efficient recording method can not only improve recording ability greatly, but also reduce the file size with the maximum FPS. Variable Frame Rate, shortly for VFR, is a term wildly used in video recording. How to Transcode VFR to a Constant Frame Rate Easily and Fast What's the Problem with Variable Frame Rate? How to Detect Whether Your Source Recording Has VFR For example, Adobe officially supports VFR video since the 12.0.1 update in early 2018, but it still gives its users some import and audio and video out of sync issues with VFR in Premiere Pro.įor those who are getting problems with editing VFR video in NLE software like Adobe Premiere Pro, DaVinci Resolve, Sony Vegas, Avid, Final Cut Pro, etc., don't waste your time on searching and trying complex troubleshooting methods in vain, transcoding VFR video to CFR/constant frame rate is the jack-of-all-trades.Įverything you need to know about Variable Frame Rate and VFR to CFR Conversion. Small indeed, but those VFR footages taken by your iPhone, iPad, Camtasia, nVidia ShadowPlay, Panasonic GH5 and such may be problematic during the process of editing and playback in the non-linear editing tools. And to capture a video at smaller size but with higher quality, most users prefer to compress video with VFR by default, known as variable frame rate. When shooting video using a smartphone (including an iPhone) the software within the phone uses compression. However, if your mp4 files are already very high quality, I expect the size difference will not be so great.įootnote 1: If you're using Microsoft Windows instead of UNIX, change /dev/null to NUL.Got a problem with editing or playing the video files with variable frame rate? Follow this tutorial to transcode the videos from VFR to CFR for further smooth processing. When I tried -lossless 1 on a low-quality mp4, the resulting webm was 100× larger, which was not accceptable to me. The -lossless 1 option of ffmpeg’s VP9 encoder enables lossless quality mode, but with a potentially enormous increase in filesize.Īll you need is this: ffmpeg -i input.mp4 -lossless 1 output.webm If you mean “without quality loss” literally ![]() A word about transcodingīy the way, in general, transcoding formats (taking a compressed video and recompressing it with a different codec) is a bad idea as you’ll not only add the normal errors from lossy video encoding, but you’ll waste bits in the new format trying to preserve the artifacts from the old. Please see the ffmpeg VP9 documentation if you’d like to learn more. The first pass compiles statistics about the video which is then used in the second pass to make a smaller and higher quality video. While that can be useful for streaming, it reduces quality significantly as frames with a lot of motion will not have the bandwidth needed to look good.Īnother part of the reason you’re losing quality is that webm (VP9) prefers to encode in two passes for best results. If you do not specify a video bitrate, it defaults to something low which gets you Constrained Quality mode, where each frame has a maximum bitrate. It is important to set the video bitrate to zero. For VP9, the CRF can range from 0 (best quality) to 63 (smallest file size). Setting the video bitrate to zero while also specifying the CRF (Constant Rate Factor) enables Constant Quality mode which targets a certain perceptual quality level. Use two-pass Constant Quality mode:¹ ffmpeg -i input.mp4 -b:v 0 -crf 30 -pass 1 -an -f webm -y /dev/nullįfmpeg -i input.mp4 -b:v 0 -crf 30 -pass 2 output.webm
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