[Libav-user] qmin qmax settings for libx265 (HEVC) not functional

[Taha Ansari]

On Fri, Jun 6, 2014 at 12:35 PM, Taha Ansari <mtaha.ansari at gmail.com> wrote:
> On Fri, Jun 6, 2014 at 12:21 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>> Taha Ansari <mtaha.ansari at ...> writes:
>>
>>> > > ffmpeg -i temp.mp4 -c:v libx265 -qmin 40 -qmax 41 output.mp4
>>> >
>>> > Why do you think that -qmin and -qmax are supported
>>> > in x265? Do you see a related option for x265?
>>>
>>> I saw this on command line while processing output stream:
>>> Stream #0:0(eng): Video: hevc (libx265) ([35][0][0][0] / 0x0023),
>>> yuv420p, 640x360 [SAR 1:1 DAR 16:9], q=40-41, 200 kb/s, 30 fps,
>>> 15360 tbn, 30 tbc (default)
>>>
>>> particularly: "q=40-41"
>>>
>>> doesn't that mean qmin/qmax settings is being passed
>>> over to libx265?
>>
>> It means that you passed the settings to ffmpeg.
>>
>> As said: Do you see a related option for the
>> x265 executable?
>>

Looking at this site:
https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping , I
can see:

--qpmin <integer> (x264)
-qmin <integer> (FFmpeg)
Minimum quantizer. Doesn't need to be changed. Recommended default: -qmin 10


--qpmax <integer> (x264)
-qmax <integer> (FFmpeg)
Maximum quantizer. Doesn't need to be changed. Recommended default: -qmax 51

That means qpmin goes to qmin, and qpmax goes to qmax in FFmpeg (for h264).

If similar is not mapped inside FFmpeg for libx265, that means
functionality is present, it is just not mapped.

Is this understanding correct?


>
> Just had a look - and could not find qmin/qmax settings. However it
> does mention "qpmin/qpmax"; are they correlated?
>
>
>> Please set your mailer to text-only.
>>
>
> done
>
>> Carl Eugen
>>
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