[x265] How to use vbv-end and vbv-init for chunked encoding

[Alex Giladi]

Hi Vassily,
I would also add that you need to set a reasonable amount of frames for the
VBV adjustment, otherwise your last frames may suffer quality-wise.
Best,
Alex.

On Wed, Mar 7, 2018 at 9:28 AM, Aruna Matheswaran <
aruna at multicorewareinc.com> wrote:

> Hi,
>
>  vbv-init specifies the portion of the vbv buffer which must be available
> before the encoder begins encoding and * vbv-end* denotes the portion of
> the vbv buffer that must be available after all the specified frames have
> been inserted into the vbv buffer.
> Therefore, while encoding multiple chunks in parallel and merging them
> into a single stream, *vbv-init of any chunk should be the same as the
> vbv-end of its previous chunk*. If vbv-end of chunk X is less than
> vbv-init of chunk X+1, there are chances for the buffer to overflow.
>
> Thanks,
> Aruna
>
> On Wed, Mar 7, 2018 at 4:43 PM, Vasiliy Volkov <volk.vasiliy at gmail.com>
> wrote:
>
>> Hi,
>>
>> Recently libx265 gets vbv-end encoding option with comment that it can be
>> used for chunked encoding. My question is how it can be used?
>>
>> Recently we've split our encoding session into multiple processes -- so
>> multiple instances of libx265 encoder encodes same stream, GOP by GOP, and
>> then such stream merges into single stream again. It works well, but rate
>> controllers are not share their states between encoders instances and I
>> think such encoding is not VBV-compliant.
>> And from comment to vbv-end option I think that it can fix it encoding.
>>
>> Can somebody explain how this option should be used and how it can helps
>> us (or maybe not and we need to find another solution)?
>>
>> For example, we use such encoding options: bitrate=4500:bufsize=10000:maxrate=5000,
>> and in such setup vbv-init by default is 0.9
>>
>> For this setup what we need to specify for vbv-end?
>>
>>
>>
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>>
>>
>
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