On Mon, Jun 18, 2012 at 04:34:04PM +0200, Christophe Gisquet wrote: > 2012/6/18 Kostya Shishkov <[email protected]>: > >> How high are the weights typically? Same for the LUT values of idx2sym > >> and sym2idx. num_syms seems to be set to 8 or 2, but there is probably > >> something I missed in between. > > > > There's one model for all pixel values (i.e. 256 symbols). > > Original decoder can have up to 1023 symbols but I have not found such large > > model anywhere. > > > >> Basically, I am wondering if a smaller type could be used. > > > > It can, but I don't think it's worth the effort (even though in practice > > probably every field can be made int8_t or uint8_t). > > Is the -1 initialization of those LUTS really needed btw? If yes (I'm > missing how, as negative values from the LUTs do not seem to be > checked), then probably int16_t is needed. > > How does the original decoder detect/what are the characteristics of a > bitstream with such values? Some "need samples" warning may be added > then.
weights[0] need it as a special guard value, others are just for internal state checking in case something goes wrong. _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
