| /* |
| * Copyright (C) 2012 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "MonoPipe" |
| //#define LOG_NDEBUG 0 |
| |
| #include <common_time/cc_helper.h> |
| #include <cutils/atomic.h> |
| #include <cutils/compiler.h> |
| #include <utils/LinearTransform.h> |
| #include <utils/Log.h> |
| #include <utils/Trace.h> |
| #include <media/AudioBufferProvider.h> |
| #include <media/nbaio/MonoPipe.h> |
| #include <media/nbaio/roundup.h> |
| |
| |
| namespace android { |
| |
| MonoPipe::MonoPipe(size_t reqFrames, NBAIO_Format format, bool writeCanBlock) : |
| NBAIO_Sink(format), |
| mUpdateSeq(0), |
| mReqFrames(reqFrames), |
| mMaxFrames(roundup(reqFrames)), |
| mBuffer(malloc(mMaxFrames * Format_frameSize(format))), |
| mFront(0), |
| mRear(0), |
| mWriteTsValid(false), |
| // mWriteTs |
| mSetpoint((reqFrames * 11) / 16), |
| mWriteCanBlock(writeCanBlock), |
| mIsShutdown(false) |
| { |
| CCHelper tmpHelper; |
| status_t res; |
| uint64_t N, D; |
| |
| mNextRdPTS = AudioBufferProvider::kInvalidPTS; |
| |
| mSamplesToLocalTime.a_zero = 0; |
| mSamplesToLocalTime.b_zero = 0; |
| mSamplesToLocalTime.a_to_b_numer = 0; |
| mSamplesToLocalTime.a_to_b_denom = 0; |
| |
| D = Format_sampleRate(format); |
| if (OK != (res = tmpHelper.getLocalFreq(&N))) { |
| ALOGE("Failed to fetch local time frequency when constructing a" |
| " MonoPipe (res = %d). getNextWriteTimestamp calls will be" |
| " non-functional", res); |
| return; |
| } |
| |
| LinearTransform::reduce(&N, &D); |
| static const uint64_t kSignedHiBitsMask = ~(0x7FFFFFFFull); |
| static const uint64_t kUnsignedHiBitsMask = ~(0xFFFFFFFFull); |
| if ((N & kSignedHiBitsMask) || (D & kUnsignedHiBitsMask)) { |
| ALOGE("Cannot reduce sample rate to local clock frequency ratio to fit" |
| " in a 32/32 bit rational. (max reduction is 0x%016llx/0x%016llx" |
| "). getNextWriteTimestamp calls will be non-functional", N, D); |
| return; |
| } |
| |
| mSamplesToLocalTime.a_to_b_numer = static_cast<int32_t>(N); |
| mSamplesToLocalTime.a_to_b_denom = static_cast<uint32_t>(D); |
| } |
| |
| MonoPipe::~MonoPipe() |
| { |
| free(mBuffer); |
| } |
| |
| ssize_t MonoPipe::availableToWrite() const |
| { |
| if (CC_UNLIKELY(!mNegotiated)) { |
| return NEGOTIATE; |
| } |
| // uses mMaxFrames not mReqFrames, so allows "over-filling" the pipe beyond requested limit |
| ssize_t ret = mMaxFrames - (mRear - android_atomic_acquire_load(&mFront)); |
| ALOG_ASSERT((0 <= ret) && (ret <= mMaxFrames)); |
| return ret; |
| } |
| |
| ssize_t MonoPipe::write(const void *buffer, size_t count) |
| { |
| if (CC_UNLIKELY(!mNegotiated)) { |
| return NEGOTIATE; |
| } |
| size_t totalFramesWritten = 0; |
| while (count > 0) { |
| // can't return a negative value, as we already checked for !mNegotiated |
| size_t avail = availableToWrite(); |
| size_t written = avail; |
| if (CC_LIKELY(written > count)) { |
| written = count; |
| } |
| size_t rear = mRear & (mMaxFrames - 1); |
| size_t part1 = mMaxFrames - rear; |
| if (part1 > written) { |
| part1 = written; |
| } |
| if (CC_LIKELY(part1 > 0)) { |
| memcpy((char *) mBuffer + (rear << mBitShift), buffer, part1 << mBitShift); |
| if (CC_UNLIKELY(rear + part1 == mMaxFrames)) { |
| size_t part2 = written - part1; |
| if (CC_LIKELY(part2 > 0)) { |
| memcpy(mBuffer, (char *) buffer + (part1 << mBitShift), part2 << mBitShift); |
| } |
| } |
| android_atomic_release_store(written + mRear, &mRear); |
| totalFramesWritten += written; |
| } |
| if (!mWriteCanBlock || mIsShutdown) { |
| break; |
| } |
| count -= written; |
| buffer = (char *) buffer + (written << mBitShift); |
| // Simulate blocking I/O by sleeping at different rates, depending on a throttle. |
| // The throttle tries to keep the mean pipe depth near the setpoint, with a slight jitter. |
| uint32_t ns; |
| if (written > 0) { |
| size_t filled = (mMaxFrames - avail) + written; |
| // FIXME cache these values to avoid re-computation |
| if (filled <= mSetpoint / 2) { |
| // pipe is (nearly) empty, fill quickly |
| ns = written * ( 500000000 / Format_sampleRate(mFormat)); |
| } else if (filled <= (mSetpoint * 3) / 4) { |
| // pipe is below setpoint, fill at slightly faster rate |
| ns = written * ( 750000000 / Format_sampleRate(mFormat)); |
| } else if (filled <= (mSetpoint * 5) / 4) { |
| // pipe is at setpoint, fill at nominal rate |
| ns = written * (1000000000 / Format_sampleRate(mFormat)); |
| } else if (filled <= (mSetpoint * 3) / 2) { |
| // pipe is above setpoint, fill at slightly slower rate |
| ns = written * (1150000000 / Format_sampleRate(mFormat)); |
| } else if (filled <= (mSetpoint * 7) / 4) { |
| // pipe is overflowing, fill slowly |
| ns = written * (1350000000 / Format_sampleRate(mFormat)); |
| } else { |
| // pipe is severely overflowing |
| ns = written * (1750000000 / Format_sampleRate(mFormat)); |
| } |
| } else { |
| ns = count * (1350000000 / Format_sampleRate(mFormat)); |
| } |
| if (ns > 999999999) { |
| ns = 999999999; |
| } |
| struct timespec nowTs; |
| bool nowTsValid = !clock_gettime(CLOCK_MONOTONIC, &nowTs); |
| // deduct the elapsed time since previous write() completed |
| if (nowTsValid && mWriteTsValid) { |
| time_t sec = nowTs.tv_sec - mWriteTs.tv_sec; |
| long nsec = nowTs.tv_nsec - mWriteTs.tv_nsec; |
| ALOGE_IF(sec < 0 || (sec == 0 && nsec < 0), |
| "clock_gettime(CLOCK_MONOTONIC) failed: was %ld.%09ld but now %ld.%09ld", |
| mWriteTs.tv_sec, mWriteTs.tv_nsec, nowTs.tv_sec, nowTs.tv_nsec); |
| if (nsec < 0) { |
| --sec; |
| nsec += 1000000000; |
| } |
| if (sec == 0) { |
| if ((long) ns > nsec) { |
| ns -= nsec; |
| } else { |
| ns = 0; |
| } |
| } |
| } |
| if (ns > 0) { |
| const struct timespec req = {0, ns}; |
| nanosleep(&req, NULL); |
| } |
| // record the time that this write() completed |
| if (nowTsValid) { |
| mWriteTs = nowTs; |
| if ((mWriteTs.tv_nsec += ns) >= 1000000000) { |
| mWriteTs.tv_nsec -= 1000000000; |
| ++mWriteTs.tv_sec; |
| } |
| } |
| mWriteTsValid = nowTsValid; |
| } |
| mFramesWritten += totalFramesWritten; |
| return totalFramesWritten; |
| } |
| |
| void MonoPipe::setAvgFrames(size_t setpoint) |
| { |
| mSetpoint = setpoint; |
| } |
| |
| status_t MonoPipe::getNextWriteTimestamp(int64_t *timestamp) |
| { |
| int32_t front; |
| |
| ALOG_ASSERT(NULL != timestamp); |
| |
| if (0 == mSamplesToLocalTime.a_to_b_denom) |
| return UNKNOWN_ERROR; |
| |
| observeFrontAndNRPTS(&front, timestamp); |
| |
| if (AudioBufferProvider::kInvalidPTS != *timestamp) { |
| // If we have a valid read-pointer and next read timestamp pair, then |
| // use the current value of the write pointer to figure out how many |
| // frames are in the buffer, and offset the timestamp by that amt. Then |
| // next time we write to the MonoPipe, the data will hit the speakers at |
| // the next read timestamp plus the current amount of data in the |
| // MonoPipe. |
| size_t pendingFrames = (mRear - front) & (mMaxFrames - 1); |
| *timestamp = offsetTimestampByAudioFrames(*timestamp, pendingFrames); |
| } |
| |
| return OK; |
| } |
| |
| void MonoPipe::updateFrontAndNRPTS(int32_t newFront, int64_t newNextRdPTS) |
| { |
| // Set the MSB of the update sequence number to indicate that there is a |
| // multi-variable update in progress. Use an atomic store with an "acquire" |
| // barrier to make sure that the next operations cannot be re-ordered and |
| // take place before the change to mUpdateSeq is commited.. |
| int32_t tmp = mUpdateSeq | 0x80000000; |
| android_atomic_acquire_store(tmp, &mUpdateSeq); |
| |
| // Update mFront and mNextRdPTS |
| mFront = newFront; |
| mNextRdPTS = newNextRdPTS; |
| |
| // We are finished with the update. Compute the next sequnce number (which |
| // should be the old sequence number, plus one, and with the MSB cleared) |
| // and then store it in mUpdateSeq using an atomic store with a "release" |
| // barrier so our update operations cannot be re-ordered past the update of |
| // the sequence number. |
| tmp = (tmp + 1) & 0x7FFFFFFF; |
| android_atomic_release_store(tmp, &mUpdateSeq); |
| } |
| |
| void MonoPipe::observeFrontAndNRPTS(int32_t *outFront, int64_t *outNextRdPTS) |
| { |
| // Perform an atomic observation of mFront and mNextRdPTS. Basically, |
| // atomically observe the sequence number, then observer the variables, then |
| // atomically observe the sequence number again. If the two observations of |
| // the sequence number match, and the update-in-progress bit was not set, |
| // then we know we have a successful atomic observation. Otherwise, we loop |
| // around and try again. |
| // |
| // Note, it is very important that the observer be a lower priority thread |
| // than the updater. If the updater is lower than the observer, or they are |
| // the same priority and running with SCHED_FIFO (implying that quantum |
| // based premption is disabled) then we run the risk of deadlock. |
| int32_t seqOne, seqTwo; |
| |
| do { |
| seqOne = android_atomic_acquire_load(&mUpdateSeq); |
| *outFront = mFront; |
| *outNextRdPTS = mNextRdPTS; |
| seqTwo = android_atomic_release_load(&mUpdateSeq); |
| } while ((seqOne != seqTwo) || (seqOne & 0x80000000)); |
| } |
| |
| int64_t MonoPipe::offsetTimestampByAudioFrames(int64_t ts, size_t audFrames) |
| { |
| if (0 == mSamplesToLocalTime.a_to_b_denom) |
| return AudioBufferProvider::kInvalidPTS; |
| |
| if (ts == AudioBufferProvider::kInvalidPTS) |
| return AudioBufferProvider::kInvalidPTS; |
| |
| int64_t frame_lt_duration; |
| if (!mSamplesToLocalTime.doForwardTransform(audFrames, |
| &frame_lt_duration)) { |
| // This should never fail, but if there is a bug which is causing it |
| // to fail, this message would probably end up flooding the logs |
| // because the conversion would probably fail forever. Log the |
| // error, but then zero out the ratio in the linear transform so |
| // that we don't try to do any conversions from now on. This |
| // MonoPipe's getNextWriteTimestamp is now broken for good. |
| ALOGE("Overflow when attempting to convert %d audio frames to" |
| " duration in local time. getNextWriteTimestamp will fail from" |
| " now on.", audFrames); |
| mSamplesToLocalTime.a_to_b_numer = 0; |
| mSamplesToLocalTime.a_to_b_denom = 0; |
| return AudioBufferProvider::kInvalidPTS; |
| } |
| |
| return ts + frame_lt_duration; |
| } |
| |
| void MonoPipe::shutdown(bool newState) |
| { |
| mIsShutdown = newState; |
| } |
| |
| bool MonoPipe::isShutdown() |
| { |
| return mIsShutdown; |
| } |
| |
| } // namespace android |
