On Fri, Jul 24, 2015 at 11:56:54AM +0300, Ivan Uskov wrote: > Hello Michael, > > Friday, July 24, 2015, 2:48:45 AM, you wrote: > > > >> + /* A decoder's latency depends not only by async_depth > >> + but by DPB size too. The latency may acheve 16 frames. > >> + So it is necessary to handle the size of async_fifo > >> dynamically: > >> + */ > >> + if (av_fifo_space(q->async_fifo) < sizeof(out_frame) + > >> sizeof(sync)) > >> + av_fifo_grow(q->async_fifo, > >> sizeof(out_frame)+sizeof(sync)); > > MN> the DPB cannot be arbitrary large, so maybe the grow code could be > MN> avoided ? > MN> or maybe i missunderstand > > As you can see, the current implementation pre-allocates async_fifo > for async_depth+1 elements where async_depth==4 by default (see > tehff_qsv_decode_init() function). > For h.264 and HEVC max DPB size is 16. So we theoretically can > hard-code 16+1 size for this fifo. > Also same code will be used for mpeg2, mjpeg, vc1 where 16+1 most > likely too big.
> Are you agree to use fixed size for fifo? yes, it seems simpler, and its only structs, not bitmaps so space wise it should not be a problem [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB It is dangerous to be right in matters on which the established authorities are wrong. -- Voltaire
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