accelerate ffmpeg

[blanc]

Hi,

my computer converts a large mp4 file very slowly: ffmpeg –i old.mp4 new.mp4

How can I accelerate this? Maybe split it into two parts and start two conversions at the same time?

[ProWo]

Hi,
my computer converts a large mp4 file very slowly: ffmpeg –i old.mp4 new.mp4
How can I accelerate this?

You can try a GPU-accelerated codec.
This shifts a large portion of the encoding work to the GPU (graphics processing unit), thereby reducing the load on the CPU. This is usually faster.
Examples are:
QSV encoder (for Intel platforms)
AMF encoder (for AMD GPUs)
NVENC encoder (for NVIDIA GPUs)

Just try one out; if the encoding fails, your hardware doesn’t support the selected encoder.

You can try out the different encoders using Clever FFmpeg-GUI.

[jagabo]

You can specify which encoder to use:

ffmpeg –i old.mp4 -c:v h264_nvenc new.mp4

Some others encoders are: libx264, h264_qsv, hevc_qsv, hevc_nvenc.

Beyond that, generally h.264 encoders are faster than h.265 encoders.

You can try using faster presets than the defaults:

ffmpeg –i old.mp4 -c:v libx264 -preset veryfast new.mp4

Other presets include: ultrafast, superfast, veryfast, faster, fast, medium (the default), slow, veryslow. Generally, the slower the preset the better the quality.

Also if you don't need to reencode the audio copy it instead, -c:a copy.

ffmpeg –i old.mp4 -c:v libx264 -preset veryfast -c:a copy new.mp4

By the way, ffmpeg automatically uses multithreading when the encoder supports it.

[cholla]

I usually use ffmpeg cli because it has more control.

Many times ProWo's Clever is faster even with the same preset.
I'm not sure why but it is.