diff options
Diffstat (limited to 'third_party/aom/aom_dsp/entcode.c')
-rw-r--r-- | third_party/aom/aom_dsp/entcode.c | 49 |
1 files changed, 0 insertions, 49 deletions
diff --git a/third_party/aom/aom_dsp/entcode.c b/third_party/aom/aom_dsp/entcode.c deleted file mode 100644 index aad96c6fc..000000000 --- a/third_party/aom/aom_dsp/entcode.c +++ /dev/null @@ -1,49 +0,0 @@ -/* - * Copyright (c) 2001-2016, Alliance for Open Media. All rights reserved - * - * This source code is subject to the terms of the BSD 2 Clause License and - * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License - * was not distributed with this source code in the LICENSE file, you can - * obtain it at www.aomedia.org/license/software. If the Alliance for Open - * Media Patent License 1.0 was not distributed with this source code in the - * PATENTS file, you can obtain it at www.aomedia.org/license/patent. - */ - -#include "aom_dsp/entcode.h" - -/*Given the current total integer number of bits used and the current value of - rng, computes the fraction number of bits used to OD_BITRES precision. - This is used by od_ec_enc_tell_frac() and od_ec_dec_tell_frac(). - nbits_total: The number of whole bits currently used, i.e., the value - returned by od_ec_enc_tell() or od_ec_dec_tell(). - rng: The current value of rng from either the encoder or decoder state. - Return: The number of bits scaled by 2**OD_BITRES. - This will always be slightly larger than the exact value (e.g., all - rounding error is in the positive direction).*/ -uint32_t od_ec_tell_frac(uint32_t nbits_total, uint32_t rng) { - uint32_t nbits; - int l; - int i; - /*To handle the non-integral number of bits still left in the encoder/decoder - state, we compute the worst-case number of bits of val that must be - encoded to ensure that the value is inside the range for any possible - subsequent bits. - The computation here is independent of val itself (the decoder does not - even track that value), even though the real number of bits used after - od_ec_enc_done() may be 1 smaller if rng is a power of two and the - corresponding trailing bits of val are all zeros. - If we did try to track that special case, then coding a value with a - probability of 1/(1 << n) might sometimes appear to use more than n bits. - This may help explain the surprising result that a newly initialized - encoder or decoder claims to have used 1 bit.*/ - nbits = nbits_total << OD_BITRES; - l = 0; - for (i = OD_BITRES; i-- > 0;) { - int b; - rng = rng * rng >> 15; - b = (int)(rng >> 16); - l = l << 1 | b; - rng >>= b; - } - return nbits - l; -} |