libx265 file size larger then libx264

[Former user]

Hello,

I'm encoding video from H264 to HEVC into a TS ready for IP distribution.

Now when encoding using libx264 the output file size is 3mb when encoding using the same settings in Libx265 the output file size is 50mb. How comes ? Surely it is spose to be more efficient correct ? Here is the Syntax I've been using:

ffmpeg -i 112.mp4 -c:v libx265 -preset medium -b:v 700k -r 25 -x2 crf=28 -s 1920x1080 -acodec copy x265manual.ts

I'm using encoder version: Lavf56.16.102 HEVC encoder version 1.2

Please let me know if the syntax is wrong for example.

Kind Regards,

Mark Couto

[Sundar Govindarajan]

The command line you have provided doesn't run with the binaries from http://ffmpeg.zeranoe.com/builds/ . It complains about -x2 cli option.

Can you share the log ?

[Former user]

Sorry it should be, -x265-params..... unsure how i missed that out.

ffmpeg -i 112.mp4 -c:v libx265 -preset medium -b:v 700k -r 25 -x265-params crf=27 -s 1920x1080 -y -acodec copy x265manual.ts

But the issue still stands !

[Sundar Govindarajan]

CRF=27 takes higher precedence as you can see from the on-screen display.. CRF doesn't guarantee a file size x265 [info]: Rate Control / AQ-Strength / CUTree : CRF-27.0 / 1.0 / 1

Try this command, if you are looking to encode at 700kbps.. ffmpeg -i 112.mp4 -c:v libx265 -preset medium -b:v 700k -r 25 -x265-params crf=27:bitrate=700 -s 1920x1080 -y -acodec copy x265manual.ts

Can you share the details of the x264 encoded file.. how it got encoded (ABR/CRF?)

[Former user]

Thanks very much for all your help thus far, I shall try that command above.

x264 got encoded in the same syntax just changing the 5 to 4

[Former user]

I'm also updating my FFMPEG version from the releases as a new version was compiled yesterday

[Former user]

After an update. libx265 is now not be being reconsigned I keep being told no encoder installed.

Using ffmpeg --help encoder=libx265

So I used the instructions on the front of this page still no luck :( help !!! I have broken my ffmpeg.

Thanks

Mark

[Former user]

Hello all managed to get the system operating again.

Still the same issue where the H264 coded file is still smaller then the H265 coded file.

With the same parameters with just he 4's turned into 5's. Could someone please explain if this is what they are seeing too.

Thanks Mark

[Sundar Govindarajan]

If you are running a crf encode, the file size will differ. try running a bitrate constrained encode and check the quality of the output.

[Former user]

I was doing some testing late last night, and did find that the file size was fluctuating however compared to libx264 the quality was amazing, so reducing the libx265 bit rate reduced the filesize.

Thanks for all your help you may class this ticket as now completed.

Kind regards,

Mark Couto

[Deepthi Nandakumar]

Clarified concerns