1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17//#define LOG_NDEBUG 0
18#define LOG_TAG "FrameDropper"
19#include <utils/Log.h>
20
21#include <media/stagefright/bqhelper/FrameDropper.h>
22#include <media/stagefright/foundation/ADebug.h>
23
24namespace android {
25
26static const int64_t kMaxJitterUs = 2000;
27
28FrameDropper::FrameDropper()
29    : mDesiredMinTimeUs(-1),
30      mMinIntervalUs(0) {
31}
32
33FrameDropper::~FrameDropper() {
34}
35
36status_t FrameDropper::setMaxFrameRate(float maxFrameRate) {
37    if (maxFrameRate < 0) {
38        mMinIntervalUs = -1ll;
39        return OK;
40    }
41
42    if (maxFrameRate == 0) {
43        ALOGE("framerate should be positive but got %f.", maxFrameRate);
44        return BAD_VALUE;
45    }
46    mMinIntervalUs = (int64_t) (1000000.0f / maxFrameRate);
47    return OK;
48}
49
50bool FrameDropper::shouldDrop(int64_t timeUs) {
51    if (mMinIntervalUs <= 0) {
52        return false;
53    }
54
55    if (mDesiredMinTimeUs < 0) {
56        mDesiredMinTimeUs = timeUs + mMinIntervalUs;
57        ALOGV("first frame %lld, next desired frame %lld",
58                (long long)timeUs, (long long)mDesiredMinTimeUs);
59        return false;
60    }
61
62    if (timeUs < (mDesiredMinTimeUs - kMaxJitterUs)) {
63        ALOGV("drop frame %lld, desired frame %lld, diff %lld",
64                (long long)timeUs, (long long)mDesiredMinTimeUs,
65                (long long)(mDesiredMinTimeUs - timeUs));
66        return true;
67    }
68
69    int64_t n = (timeUs - mDesiredMinTimeUs + kMaxJitterUs) / mMinIntervalUs;
70    mDesiredMinTimeUs += (n + 1) * mMinIntervalUs;
71    ALOGV("keep frame %lld, next desired frame %lld, diff %lld",
72            (long long)timeUs, (long long)mDesiredMinTimeUs,
73            (long long)(mDesiredMinTimeUs - timeUs));
74    return false;
75}
76
77}  // namespace android
78