[x264-devel] Re: [patch] split slice nal unit when it exceeds size x

[Sergey A. Sablin]

basically standard compliant streams doesn't contain last mb number 
inside - only the number of first mb in slice.

Sergey.


Alex Izvorski wrote:
> On Tue, 2007-05-01 at 14:25 -0700, Tom Harper wrote: 
>   
>> Dear X264 maintainers,
>>
>> This is a new patch that uses the existing API to start a new
>> NAL when a NAL exceeds a given size threshold.
>>
>> Haven't tested it with threading but it should work as it doesn't
>> change anything in the threading pathway.  I have an adjoining
>> patch in ffmpeg for setting the threshold there also but I will
>> wait and see what happens here first.
>>
>> Thanks!
>>
>> Tom
>>     
>
> Hi Tom,
>
> This is great!  A very nice feature addition (or is it re-addition? ;)
>
> Could you modify the patch to do a fixed number of slices of the same
> number of mb's/rows of mb's, as well as what it does now?
>
> Also, could you make x264_slice_write() write only one slice at a time?
> Single calls would have to be replaced with something along the lines of
> while (! done) { x264_slice_write() } loop.  Alternately, just move the
> body of that routine into x264_slices_write().  I know this is splitting
> hairs but it is weird that both x264_slices_write and x264_slice_write
> do in fact write multiple slices right now ;)  The old slice code had
> x264_slice_write do just one slice at a time, and x264_slices_write do
> an entire frame.
>
> Lastly, correct me if I'm wrong, but it seems at a glance that all
> slices written will have sh.i_last_mb equal to the last mb of the whole
> frame?  Since the header gets written first and only some time later
> does the termination condition (by size) get met.  I haven't examined an
> output stream in detail to see if that is indeed the case, but it looks
> that way from the source.  If so, for a standards compliant stream the
> order would have to be reversed, write the slice body first (perhaps to
> a temp buffer), then the header, so the header can list the correct last
> mb number.
>
> Regards,
> --Alex
>
>
>   

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