[FFmpeg-devel] [PATCH] libavutil: AVEncodeInfo data structures

[Juan De León]

Pinging,
Any other opinions?

On Sat, Aug 10, 2019 at 2:22 AM Nicolas George <george at nsup.org> wrote:

> Lynne (12019-08-10):
> > >> +typedef struct AVEncodeInfoBlock{
> > >> +    /**
> > >> +     * Distance in luma pixels from the top-left corner of the
> visible frame
> > >> +     * to the top-left corner of the block.
> > >> +     * Can be negative if top/right padding is present on the coded
> frame.
> > >> +     */
> > >> +    int src_x, src_y;
> > >> +    /**
> > >> +     * Width and height of the block in luma pixels
> > >> +     */
> > >> +    int w, h;
> > >> +    /**
> > >> +     * Delta quantization index for the block
> > >> +     */
> > >> +    int delta_q;
> > >> +
> > >>
> > >> +    uint8_t reserved[128];
> > >>
> > > What are these (this one and the one below) reserved fields for?
> >
> > For future extensions without breaking the API. Things like block type,
> prediction type, motion vectors, references, etc.
>
> I suspected as much. But remember that setting the size of reserved
> after fields are added will be very tricky: it requires taking into
> account alignment and padding in the structure.
>
> I think something like that might be easier to manage (and also use less
> memory right now):
>
> typedef struct AVEncodeInfoFrame {
>     ...
>     size_t blocks_offset;
>     size_t block_size;
> }
>
> static inline AVEncodeInfoBlock *
> av_encode_info_block(AVEncodeInfoFrame *info, unsigned idx)
> {
>     return (AVEncodeInfoBlock *)
>            ((char *)info + info->blocks_offset +
>             idx * info->block_size);
> }
>
> static inline AVEncodeInfoBlock *
> av_encode_info_block_next(AVEncodeInfoFrame *info, AVEncodeInfoBlock
> *block)
> {
>     return (AVEncodeInfoBlock *)
>            ((char *)block + info->block_size);
> }
>
> Regards,
>
> --
>   Nicolas George
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