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

[Aruna Matheswaran]

 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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