Equivalent parameter for CRF in hevc_videotoolbox

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Equivalent parameter for CRF in hevc_videotoolbox

桃源老師-2
Hello list member,

I recently noticed that ffmpeg can use hardware acceleration via videotoolbox on Mac.

Before above discovery, I use the command like as follows:

ffmpeg -i DR08.ts -c:v libx265 -preset medium -crf 23 -tag:v hvc1 -vsync 1 -c:a copy -bsf:a aac_adtstoasc DR08.mp4

Now I noticed that CRF does not work on hevc_videotoolbox codec.  Based on very rough trying, -b:v only changes quality of encoded video.

So my question is is there equivalent parameter for CRF in hevc_videotoolbox codec or not.  In another word, how to set quality of hardware acceleration of video?

I have googled about this, but I can’t get the answer.  So please help me!!


// Miya aka. TougenRoushi


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Re: Equivalent parameter for CRF in hevc_videotoolbox

Carl Eugen Hoyos-2
2018-12-05 15:54 GMT+01:00, 桃源老師 <[hidden email]>:

> I recently noticed that ffmpeg can use hardware acceleration via
> videotoolbox on Mac.

Since 2016;-)

> Before above discovery, I use the command like as follows:
>
> ffmpeg -i DR08.ts -c:v libx265 -preset medium -crf 23 -tag:v hvc1 -vsync 1
> -c:a copy -bsf:a aac_adtstoasc DR08.mp4
>
> Now I noticed that CRF does not work on hevc_videotoolbox codec.  Based on
> very rough trying, -b:v only changes quality of encoded video.
>
> So my question is is there equivalent parameter for CRF in hevc_videotoolbox
> codec or not.  In another word, how to set quality of hardware acceleration
> of video?

Only constant bitrate (or whatever the Apple driver does with the
bitrate, could be adaptive bitrate or similar) is currently supported
for the videotoolbox encoder.

Sorry for the late answer, Carl Eugen
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Re: Equivalent parameter for CRF in hevc_videotoolbox

桃源老師-2
Hello Carl-san,

> 2019/01/16 午前9:46、Carl Eugen Hoyos <[hidden email]>のメール:
>
> 2018-12-05 15:54 GMT+01:00, 桃源老師 <[hidden email]>:
>
>> I recently noticed that ffmpeg can use hardware acceleration via
>> videotoolbox on Mac.
>
> Since 2016;-)

My god!! ;-)

>
>> So my question is is there equivalent parameter for CRF in hevc_videotoolbox
>> codec or not.  In another word, how to set quality of hardware acceleration
>> of video?
>
> Only constant bitrate (or whatever the Apple driver does with the
> bitrate, could be adaptive bitrate or similar) is currently supported
> for the videotoolbox encoder.

I understand.  Thanks for your answer.


// Miya aka. TougenRoushi


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