[x265] Dynamic rate control

[Deepthi Nandakumar]

x265_encoder_reconfig does not work yet for bitrate changes.

Yes, as Mario says, I can't imagine encoder reconfiguring to be a good
solution for adaptive streaming. x265 (and x264) ratecontrol needs some
history to "learn" and adapt to content, and bitrate-keeping accuracy is
poor for the first couple of seconds.

On Tue, Oct 13, 2015 at 11:42 AM, Mario *LigH* Rohkrämer <contact at ligh.de>
wrote:

> Am 12.10.2015, 18:07 Uhr, schrieb Ralf Globisch <rglobisch at csir.co.za>:
>
> Hi,
>>
>> I'm trying to use x265 in a adaptive streaming scenario i.e. adapting to
>> network conditions.
>>
>> Calling x265_encoder_reconfig to change the bitrate does not work.Is
>> there a way of doing this without closing and re-opening the codec?
>>
>> I've tried the following:
>>
>> x265_param* params;
>> x265_encoder* encoder;
>> ....
>> params->rc.bitrate = uiNewTargetBitrate;
>> int res = x265_encoder_reconfig(encoder, params);
>>
>> While the call does not fail, it doesn't seem to affect the rate.
>>
>> Thanks,
>> Ralf
>>
>
> So you are using a client-to-server feedback control, trying to control
> the video bitrate based on the download speed, in a realtime encode
> scenario?
>
> The usual approach I knew so far was providing several video streams with
> different setups and switching between them (like in MPEG DASH, as used by
> YouTube for HD video features).
>
> I don't know the interna, but I could imagine that reconfiguring the
> bitrate control will have a quite slow effect, probably only from the next
> GOP on, when it comes to effect at all. I wonder if you may have to force a
> kind of encoder reset after reconfiguring... Just a thought.
>
> --
>
> Fun and success!
> Mario *LigH* Rohkrämer
> mailto:contact at ligh.de
>
>
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>



-- 
Deepthi Nandakumar
Engineering Manager, x265
Multicoreware, Inc
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