On Mon, Apr 15, 2013 at 09:25:22AM +0200, Kostya Shishkov wrote: > On Mon, Apr 15, 2013 at 08:31:46AM +0200, Nicolas BERTRAND wrote: > > Le 15/04/2013 06:15, Kostya Shishkov a écrit : > > >a) make FATE test account for fuzziness of the result > > ?? > > We have tests for audio that allow result to be slightly different from the > reference - exactly because of floats. > > > >b) add lots of round() and forget about performance in principle > > Performance is already crap > > But then it won't be possible to improve it much even with SIMD. > > > >c) add an integer version of IDWT (even if only for bitexact tests) > > Thats may be not possible. in JPEG2000 2 cases ( lossy, and > > lossless) . lossy float IDWT lossless integer IDWt. And its 2 > > separate algos ( duabechies 9/7 and daubechies 5/3). Dcinema case is > > always lossy > > One can always approximate. With JPEG-1992 DCT is also defined with > floating-point coefficients yet many implementations use integers.
To give a more specific example: p[2 * i + 1] -= LFTG_GAMMA * (p[2 * i] + p[2 * i + 2]); can be replaced with p[2 * i + 1] -= (57862 * (p[2 * i] + p[2 * i + 2]) + (1 << 15)) >> 16; for integer p (57862 = LFTG_GAMMA * (1 << 16) if it's not clear) _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
