1080p to 720p converter that converts very fast

Question

Any ideas about a good 1080p to 720p converter that is able to convert a video of 90 minutes in less than several hours? (maybe like in 2, 3 or 4 hours ;-)
The compression of a file is H.264/MPEG-4 AVC.

Answer 1

If you want to stay with H.264, you'll probably want to go with x264 as encoder. It's built into many applications, but most prominently FFmpeg with the "libx264" codec, or Handbrake.

x264 has a reputation of being fast and efficient. The speed can be tuned by presets that are called, for example, "fast". They range from "ultrafast" to "veryslow". You can check x264's help by calling x264 --fullhelp, which will explain all the options for the presets.

Here are the flags for "ultrafast". They disable some advanced encoding functions that require processing time. Encoding in "ultrafast" mode will not be as efficient in terms of bits used, and with a fixed bit rate, you'll lose some quality. But generally, it shouldn't matter as much.

--no-8x8dct --aq-mode 0 --b-adapt 0
--bframes 0 --no-cabac --no-deblock
--no-mbtree --me dia --no-mixed-refs
--partitions none --rc-lookahead 0 --ref 1
--scenecut 0 --subme 0 --trellis 0
--no-weightb --weightp 0

---

Handbrake

You can for example enter them in Handbrake's option string when looking under "Advanced":

Just copy this string, found here:

ref=1:bframes=0:cabac=0:8x8dct=0:weightp=0:me=dia:subq=0:rc-lookahead=0:analyse=none:trellis=0:aq-mode=0:no-deblock=1:scenecut=0:mbtree=0

Don't forget to rescale by going to the Picture Settings.

---

FFmpeg

Or, use them in FFmpeg by simply calling the right preset:

ffmpeg -i input.mp4 -vcodec libx264 -preset ultrafast -s 1280x720 -acodec copy output.mp4

Answer 2

I use Handbrake for all my conversions. But I can't tell how fast will it be for you.