FFmpeg preset comparison x265 2019; Encode speed and file size

FFmpeg preset is the value in which speed the media encode will traverse at.

Part 1 was x264

In this part 2 of FFmpeg encoding comparisons I look at x265 presets, their speed and output file size.

x265 or HEVC is a more modern codex than x264 (h.264), it is harder on the CPU and takes longer. Not all devices can play (decode) x265 either, although in recent years this has become less of a problem.

You can read more about x265 here.

The unspecified source video file used for this comparison was: 24,000,564KB in size, 1920×1080 @ 19,194Kb/s .MKV format.

The server i used to run these FFmpeg encoding comparisons was: 2x E5-2650 v2 @2.60GHz (16 cores, 32 threads), 64GB ram, SSD.

Before undertaking the testing I was well aware that x265 will take longer to encode and the files sizes will be smaller than the same preset with x264.

Preset comparisons

Lets see:

Charts

Graph showing the encode speeds for all FFmpeg x265 presets, time is in seconds

Graph showing the encoded output file size for all FFmpeg x265 presets (KB)

Graph showing the Kbit rate encoded for all FFmpeg x265 presets

x265 is a better encoder than x264, that’s technology progression. You will find that veryslow is bigger than ultrafast because the ultrafast file will be poorer quality. x265 is about quality rather than speed/size. The ‘slower’ presets actually take the time to better analyze and encode the media than a fast preset which is all about compacting the file quickly.

Fast and faster is the sweet spot for speed to file size. As you push down to medium and slow the time grows massively.

Part 3 compares x264 to x265