Two-pass example ffmpeg -y -i input.avi -c:v mpeg4 -vtag xvid -b:v 555k -pass 1 -an -f avi /dev/nullįfmpeg -i input.avi -c:v mpeg4 -vtag xvid -b:v 555k -pass 2 -c:a libmp3lame -b:a 128k output. (50 MB * 8192 ) / 600 seconds = ~683 kilobits/s total bitrateĦ83k - 128k (desired audio bitrate) = 555k video bitrate Adapting an example from the x264 encoding guide: your video is 10 minutes (600 seconds) long and an output of 50 MB is desired. This is best used with two-pass encoding. Note that if you choose it, libxvid will take much more space than the same video compressed with the native mpeg4 encoder. There is rarely a need to use -qscale:v 1. Since this guide uses libmp3lame see the MP3 Encoding Guide for examples and more information.įfmpeg -i input.avi -c:v mpeg4 -vtag xvid -qscale:v 3 -c:a libmp3lame -qscale:a 4 output.avi The value changes depending on the audio encoder. You can select an audio quality level with -qscale:a (or the alias -q:a).

Most of the time this should be the preferred method. Using variables and for loops in a command string simplifies the reuse of existing scripts and helps automate their operation.

This is a variable bit rate mode, roughly analogous to using -qp (constant QP ) with x264. FFmpeg was designed as a cross-platform solution for video and audio recording, conversion, and streaming using simple static command lines.

You can select a video quality level with -qscale:v n (or the alias -q:v n), where n is a number from 1-31, with 1 being highest quality/largest filesize and 31 being the lowest quality/smallest filesize. These codecs will offer better compression efficiency using modern containers like MP4 or MKV is also recommended. See the H.264 and AAC encoding guides if you are using modern devices. Note: This guide uses the AVI container files for the examples, as the most common usage of XviD video is currently for older hardware devices.

Mp4 to ffmpeg