[FFmpeg-user] How can I reduce compression with libx265?

Mark Filipak markfilipak.windows+ffmpeg at gmail.com
Tue Mar 31 04:15:20 EEST 2020

On 03/30/2020 10:34 AM, Moritz Barsnick wrote:
> On Mon, Mar 30, 2020 at 10:03:26 -0400, Mark Filipak wrote:
>> The x265 coder is documented here:
>> https://ffmpeg.org/ffmpeg-codecs.html#libx265
>> There's no documentation in the documentation -- I would write "There's no 'there' there" but the
>> younger audience wouldn't know to what I refer.
> Very well explained here:
> https://trac.ffmpeg.org/wiki/Encode/H.265#Ratecontrolmodes
> I usually use CRF (as with libx264).
>> How can I reduce compression with libx265? Is 'preset' the way? Is 'tune' the way. There's not only
>> no documentation for them, there's not even an indication of parameter type or range (or even if
>> they take parameters -- the lack of documentation is shameful).
> The relation to presets is also explained.

Hi Moritz,

And thanks so much. If you could see me, you'd see my big smile. That stuff at the end of those 
links could be the documentation for HandBrake! (which also has little documentation). ...The 
HandBrake folks insist that HB is not an ffmpeg frontend... It is to laugh.

You know, it would be really helpful if someone would simply put those links in the ffmpeg coder 
documentation for libx264 & libx265.

Kindly thank whomever wrote that stuff.

...Next day...
I submitted this command line:

ffmpeg -i IN.M2TS -vf "telecine=pattern=5555,bwdif=mode=send_frame" -c:v libx265 -crf 20 -preset 
slow -c:a copy -c:s copy OUT.MKV

and paused this message and went to bed.

...Today (right now) I'm viewing OUT.MKV. It is the most awesome transcode I've ever seen. The 
5-5-5-5 telecine works as I'd hoped it would, as I knew it would. It is the first ffmpeg success 
I've had.

Thank you all for your help. Joy, joy, joy.


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