[x264-devel] Multislicing support

[Etienne Bömcke]

I noticed that encoding a sequence in multiple slices breaks the rate  
control part of x264. It seems that the rate control is applied to  
each slice separatly, resulting in a global bitrate of n times the  
desired bitrate, n being the number of slices. Could anyone familiar  
with this part of the code point me to where I should look to resolve  
this issue? By the way, does the standard tell how the bitrate should  
be distributed to each slice?

Etienne

On 07 Jan 2008, at 18:46, Etienne Bömcke wrote:

>
> On 07 Jan 2008, at 18:01, Etienne Bömcke wrote:
>
>> There's nothing wrong with them I guess. I'm working on an  
>> application
>> that needs to be able to replace a bottom slice by a completely
>> different video sequence. So I cannot have motion vectors for
>> macroblocks of the upper slice linking to any macroblock of the  
>> bottom
>> one, or else when switching slices artefacts would appear in the  
>> upper
>> part of the sequence.
> Just a precision : I'm aware that this feature is not part of the
> standard H.264 definition, so I was planning on an additional command-
> line parameter alowing the user to choose between standard slices
> (independant in term of intra-prediction only) and fully independant
> slices (both intra and inter-prediction).
>
> Etienne
>
>>
>> I tried to modify the x264_mb_analyse_init function. It seems that
>> adjusting the values of mb.mv_min[] and mb.mv_max[] relatively to the
>> slice being encoded is sufficient to obtain perfectly independent
>> slices. Is there anything wrong with this method?
>>
>> Etienne
>>
>> On 07 Jan 2008, at 17:46, Loren Merritt wrote:
>>
>>> On Mon, 7 Jan 2008, Etienne Bömcke wrote:
>>>
>>>> I still have to define additional constraints to disable usage of
>>>> motion vectors liking two different slices.
>>>
>>> What's wrong with the mv constraints in x264_macroblock_cache_load?
>>>
>>> --Loren Merritt_______________________________________________
>>> x264-devel mailing list
>>> x264-devel at videolan.org
>>> http://mailman.videolan.org/listinfo/x264-devel
>>
>> --
>> Etienne Bömcke
>> UCL - Laboratoire TELE
>> etienne.bomcke at uclouvain.be
>>
>>
>>
>> _______________________________________________
>> x264-devel mailing list
>> x264-devel at videolan.org
>> http://mailman.videolan.org/listinfo/x264-devel
>
> --
> Etienne Bömcke
> UCL - Laboratoire TELE
> etienne.bomcke at uclouvain.be
>
>
>
> _______________________________________________
> x264-devel mailing list
> x264-devel at videolan.org
> http://mailman.videolan.org/listinfo/x264-devel

--
Etienne Bömcke
UCL - Laboratoire TELE
etienne.bomcke at uclouvain.be