[FFmpeg-user] Can this trigger VBR encoding for x264, x265, and libvvenc ?

[Ferdi Scholten]

Okay, thank you sir.
> Should I keep the bufsize 5 times that of maxrate ? Will that help in
> effective allocation of bitrates ? Also, for getting the best possible
> quality in this case, how high should be the value of bufsize ? What is
> your recommendation ?
>
>   (I use the slow preset for both x264 and x265 for getting better quality
> at same filesizes btw).
>
> On Wed, 30 Oct, 2024, 6:25 pm Ferdi Scholten,<ferdi at sttc-nlp.nl>  wrote:
>
>> If I set " -b:v 5000k -maxrate 6000k -minrate 4000k " for x264, x265 and
>>> vvenc, will this enable VBR encoding for these three encoders ?
>>> _______________________________________________
>>>
>> If "constrained VBR" is what you want then the answer is yes.
>>
>> It is not true VBR because it will never get below minrate or above
>> maxrate even if it would be possible/necessary for maintaining the
>> encoding quality
>> _______________________________________________
>>
try to see it like this, the bufsize/maxrate is the frequency at which 
ffmpeg checks for the need of changing the bitrate.
This is of course highly dependent on the type of content you have. 
Detailed content with high motion and/or lots of scene changes will do 
best with bufsize = maxrate, while for more static content bufsize can 
be >= 5 times maxrate.