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/*
* Copyright (c) 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 <math.h>
#include <stdlib.h>
#include <string.h>
#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
#include "test/acm_random.h"
#include "aom/aom_integer.h"
#include "aom_dsp/bitreader.h"
#include "aom_dsp/bitwriter.h"
using libaom_test::ACMRandom;
namespace {
const int num_tests = 10;
} // namespace
TEST(AV1, TestBitIO) {
ACMRandom rnd(ACMRandom::DeterministicSeed());
for (int n = 0; n < num_tests; ++n) {
for (int method = 0; method <= 7; ++method) { // we generate various proba
const int kBitsToTest = 1000;
uint8_t probas[kBitsToTest];
for (int i = 0; i < kBitsToTest; ++i) {
const int parity = i & 1;
/* clang-format off */
probas[i] =
(method == 0) ? 0 : (method == 1) ? 255 :
(method == 2) ? 128 :
(method == 3) ? rnd.Rand8() :
(method == 4) ? (parity ? 0 : 255) :
// alternate between low and high proba:
(method == 5) ? (parity ? rnd(128) : 255 - rnd(128)) :
(method == 6) ?
(parity ? rnd(64) : 255 - rnd(64)) :
(parity ? rnd(32) : 255 - rnd(32));
/* clang-format on */
}
for (int bit_method = 0; bit_method <= 3; ++bit_method) {
const int random_seed = 6432;
const int kBufferSize = 10000;
ACMRandom bit_rnd(random_seed);
aom_writer bw;
uint8_t bw_buffer[kBufferSize];
aom_start_encode(&bw, bw_buffer);
int bit = (bit_method == 0) ? 0 : (bit_method == 1) ? 1 : 0;
for (int i = 0; i < kBitsToTest; ++i) {
if (bit_method == 2) {
bit = (i & 1);
} else if (bit_method == 3) {
bit = bit_rnd(2);
}
aom_write(&bw, bit, static_cast<int>(probas[i]));
}
aom_stop_encode(&bw);
aom_reader br;
aom_reader_init(&br, bw_buffer, bw.pos);
bit_rnd.Reset(random_seed);
for (int i = 0; i < kBitsToTest; ++i) {
if (bit_method == 2) {
bit = (i & 1);
} else if (bit_method == 3) {
bit = bit_rnd(2);
}
GTEST_ASSERT_EQ(aom_read(&br, probas[i], NULL), bit)
<< "pos: " << i << " / " << kBitsToTest
<< " bit_method: " << bit_method << " method: " << method;
}
}
}
}
}
#define FRAC_DIFF_TOTAL_ERROR 0.18
TEST(AV1, TestTell) {
const int kBufferSize = 10000;
aom_writer bw;
uint8_t bw_buffer[kBufferSize];
const int kSymbols = 1024;
// Coders are noisier at low probabilities, so we start at p = 4.
for (int p = 4; p < 256; p++) {
double probability = p / 256.;
aom_start_encode(&bw, bw_buffer);
for (int i = 0; i < kSymbols; i++) {
aom_write(&bw, 0, p);
}
aom_stop_encode(&bw);
aom_reader br;
aom_reader_init(&br, bw_buffer, bw.pos);
uint32_t last_tell = aom_reader_tell(&br);
uint32_t last_tell_frac = aom_reader_tell_frac(&br);
double frac_diff_total = 0;
GTEST_ASSERT_GE(aom_reader_tell(&br), 0u);
GTEST_ASSERT_LE(aom_reader_tell(&br), 1u);
ASSERT_FALSE(aom_reader_has_overflowed(&br));
for (int i = 0; i < kSymbols; i++) {
aom_read(&br, p, NULL);
uint32_t tell = aom_reader_tell(&br);
uint32_t tell_frac = aom_reader_tell_frac(&br);
GTEST_ASSERT_GE(tell, last_tell)
<< "tell: " << tell << ", last_tell: " << last_tell;
GTEST_ASSERT_GE(tell_frac, last_tell_frac)
<< "tell_frac: " << tell_frac
<< ", last_tell_frac: " << last_tell_frac;
// Frac tell should round up to tell.
GTEST_ASSERT_EQ(tell, (tell_frac + 7) >> 3);
last_tell = tell;
frac_diff_total +=
fabs(((tell_frac - last_tell_frac) / 8.0) + log2(probability));
last_tell_frac = tell_frac;
}
const uint32_t expected = (uint32_t)(-kSymbols * log2(probability));
// Last tell should be close to the expected value.
GTEST_ASSERT_LE(last_tell, expected + 20) << " last_tell: " << last_tell;
// The average frac_diff error should be pretty small.
GTEST_ASSERT_LE(frac_diff_total / kSymbols, FRAC_DIFF_TOTAL_ERROR)
<< " frac_diff_total: " << frac_diff_total;
ASSERT_FALSE(aom_reader_has_overflowed(&br));
}
}
TEST(AV1, TestHasOverflowed) {
const int kBufferSize = 10000;
aom_writer bw;
uint8_t bw_buffer[kBufferSize];
const int kSymbols = 1024;
// Coders are noisier at low probabilities, so we start at p = 4.
for (int p = 4; p < 256; p++) {
aom_start_encode(&bw, bw_buffer);
for (int i = 0; i < kSymbols; i++) {
aom_write(&bw, 1, p);
}
aom_stop_encode(&bw);
aom_reader br;
aom_reader_init(&br, bw_buffer, bw.pos);
ASSERT_FALSE(aom_reader_has_overflowed(&br));
for (int i = 0; i < kSymbols; i++) {
GTEST_ASSERT_EQ(aom_read(&br, p, NULL), 1);
ASSERT_FALSE(aom_reader_has_overflowed(&br));
}
// In the worst case, the encoder uses just a tiny fraction of the last
// byte in the buffer. So to guarantee that aom_reader_has_overflowed()
// returns true, we have to consume very nearly 8 additional bits of data.
// In the worse case, one of the bits in that byte will be 1, and the rest
// will be zero. Once we are past that 1 bit, when the probability of
// reading zero symbol from aom_read() is high, each additional symbol read
// will consume very little additional data (in the case that p == 255,
// approximately -log_2(255/256) ~= 0.0056 bits). In that case it would
// take around 178 calls to consume more than 8 bits. That is only an upper
// bound. In practice we are not guaranteed to hit the worse case and can
// get away with 174 calls.
for (int i = 0; i < 174; i++) {
aom_read(&br, p, NULL);
}
ASSERT_TRUE(aom_reader_has_overflowed(&br));
}
}
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