The range of the quantizer scale is 0-51 where 0 is lossless, 23 is default, and 51 is worst possible. The downside is that you can't tell it to get a specific filesize or not go over a specific size or bitrate. Each frame gets the bitrate it needs to keep the requested quality level. This provides maximum compression efficiency with a single pass. This method allows the encoder to attempt to achieve a certain output quality for the whole file when output file size is of less importance. If you need help compiling and installing lib x264 see one of our FFmpeg and x264 compiling guides. This will determine the file size and also how quality is distributed. The rate control is a method that will decide how many bits will be used for each frame. There are two rate control modes that are usually suggested for general use: Constant Rate Factor (CRF) or Two-Pass ABR. The goal of this guide is to inform new users how to create a high-quality H.264 video. Is there a good workaround to make -crf work again?įfmpeg version N-78958-g8c24523 Copyright (c) 2000-2016 the FFmpeg developersīuilt with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.X264 is a H.264/MPEG-4 AVC encoder. b:v 2000k works perfectly well but I cant check the resolution of a few 100 movies to change the -b:v every time. a video option with no video streams) or that it is a private option of some encoder which was not actually used for any stream.įFmpeg simply ignores the -crf option and converts every movie with 2000kbit even if its a shitty 320x200 movie. The most likely reason is either wrong type (e.g. Good news is: Its working and its really really fast.Ĭodec AVOption crf (Select the quality for constant quality mode) specified for output file #0 (2Fast2Furious(1080p HD).m4v) has not been used for any stream.

I want to convert a lot of movies from h.264 to the new h.265 codex.

Ffmpeg crf