Why Handbrake and FFmpeg MP4/x.264 conversion speeds are so different?

[falco2000]

Hello everybody. Yesterday I did some tests converting an MPEG-2 movie to MP4/x.264, several times using Handbrakes and several times using FFmpeg command line.

Well, although the format settings (bitrate, for example) were equal or similar (for the audio stream too):

- Handbrake converted the movie very fastly (an average of 200 frames elaborated per second)

- FFmpeg converted the same movie veeeery slowly (values from 3 to 20 frames elaborated per second)

I used simple settings, nothing in particular, maybe just a conversion of the video&audio bitrates. For example, one of the test with FFmpeg was:

ffmpeg -i xyz.mpg" -c:v libx264 -b:v 400k -c:a libmp3lame -b:a 128k test.mp4

Why FFmpeg has been so much slow?

Any help will be greatly appreciated!

[Hoser Rob]

All I can suggest is that there is a lot more to settings than bit rate. Are you really sure one wasn't set to one pass and the other 2 pass?

Program defaults vary ... actually handbrake's defaults tend to lower quality than I want to use, they're meant more for mobiles ... but not that much.

[falco2000]

Are you really sure one wasn't set to one pass and the other 2 pass?

I'm sure, but you saw the FFmpeg string (no 2-pass, I've seen it during the encoding too) and if was Handbrake the one that had 2-pass, FFmpeg shouldn't be so much slow; on the contrary, Handbrake should have been...

Any way, setting FFmpeg with no audio o audio copy (see below), the frames elaboration rate is always slow (about 15 fps average):

ffmpeg -i xyz.mpg" -c:v libx264 -b:v 400k -map 0:v test.mp4

ffmpeg -i xyz.mpg" -c:v libx264 -b:v 400k -c:a copy test.mp4

[poisondeathray]

Because you might be using different settings it can be 10x faster or 20x slower depending on the settings used

Use mediainfo view=>text on the encoded file and there will be metadata as to what settings were actually used

I think ffmpeg might be using the normal preset, handbrake a faster preset

You can read about the basic settings here, although the switches are slightly different for ffmpeg than x264
http://mewiki.project357.com/wiki/X264_Settings

ffmpeg libx264
https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping

[falco2000]

Oops, I'm so sorry. I did a test with Handbrake and it runs at 30 fps, not 200

I surely did some mistakes with the previous tests. Please forget this thread and forgive me

Thank you the same for your useful answers!