Non-blocking audio I/O interface, WIP
Yet another abstraction similar to AudioTrack::Buffer and AudioBufferProvider,
but with support for streaming, non-blocking, and eventually PTS.
This is intended to be used as follows:
- primary HAL output stream implements a Sink
- primary HAL input stream implements a Source
- Pipe implements a Sink
- PipeReader implements a Source or TimedSource (not shown yet),
which supports "read at PTS"
- fast AudioTrack on server side will implement a Source using cblk
- normal AudioTrack on server side will not be changed initially
- fast AudioRecord on server side will implement a Sink using cblk
- normal AudioRecord on server side will not be changed initially
- fast mixer thread will read from Sources and write to a Sink,
or (unlikely) implement a Source and multiple Sinks
- Visualization and PCM logger will read from Source or TimedSource
- A2DP normal mixer will be connected directly to its output stream
and there will be a kind of OutputTrack for duplication that will
read from a Sink with non-blocking write fed by the fast mixer.
Patch set 3 changes:
- Add more implementations of NBAIO interfaces:
added SourceAudioBufferProvider, MonoPipe, MonoPipeReader.
- Added Format_sampleRate and Format_channelCount.
- Extract out the roundUp() method.
- Respond to most comments from previous code review.
- The new classes are untested.
Patch set 4 changes:
- Fix bugs in MonoPipe::write() and MonoPipeReader::read()
- Fix bug initializing mFrameBitShift too early
- renamed roundUp() to roundup()
- Fix Android.mk
- Add LOG_TAG an LOG_NDEBUG, use ALOG_ASSERT and utils/Log.h instead of assert
- Fix build warnings
- Move constructor and destructor bodies from .h to .cpp
- Line length 100
- Following naming conventions for #include double-include protector macros
- Include what you use
- More NBAIO logging
- MonoPipe write can be blocking
Patch set 5 changes:
- Address code review comments
- Use a static library so unused implementations don't take memory
- Comment out libsndfile dependency
- Remove debugging LOGV and LOG_NDEBUG
Patch set 6 changes (would be 6 at old location, actually 2 at new location):
- Address code review comments on patchset 5
- For MonoPipe, allow the full pipe to be used, no need to omit one slot
- Don't do atomic releasing stores unless needed
Still to do:
- I'm not happy with the Pipe class names
- Update build/ for new static library?
Change-Id: Ie6c61f05ce06b676b033be448a8ef9025a2ffcfd
diff --git a/services/audioflinger/NBAIO.cpp b/services/audioflinger/NBAIO.cpp
new file mode 100644
index 0000000..9d71eae
--- /dev/null
+++ b/services/audioflinger/NBAIO.cpp
@@ -0,0 +1,189 @@
+/*
+ * 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 "NBAIO"
+//#define LOG_NDEBUG 0
+
+#include <utils/Log.h>
+#include "NBAIO.h"
+
+namespace android {
+
+size_t Format_frameSize(NBAIO_Format format)
+{
+ switch (format) {
+ case Format_SR44_1_C2_I16:
+ case Format_SR48_C2_I16:
+ return 2 * sizeof(short);
+ case Format_SR44_1_C1_I16:
+ case Format_SR48_C1_I16:
+ return 1 * sizeof(short);
+ case Format_Invalid:
+ default:
+ return 0;
+ }
+}
+
+size_t Format_frameBitShift(NBAIO_Format format)
+{
+ switch (format) {
+ case Format_SR44_1_C2_I16:
+ case Format_SR48_C2_I16:
+ return 2; // 1 << 2 == 2 * sizeof(short)
+ case Format_SR44_1_C1_I16:
+ case Format_SR48_C1_I16:
+ return 1; // 1 << 1 == 1 * sizeof(short)
+ case Format_Invalid:
+ default:
+ return 0;
+ }
+}
+
+unsigned Format_sampleRate(NBAIO_Format format)
+{
+ switch (format) {
+ case Format_SR44_1_C1_I16:
+ case Format_SR44_1_C2_I16:
+ return 44100;
+ case Format_SR48_C1_I16:
+ case Format_SR48_C2_I16:
+ return 48000;
+ case Format_Invalid:
+ default:
+ return 0;
+ }
+}
+
+unsigned Format_channelCount(NBAIO_Format format)
+{
+ switch (format) {
+ case Format_SR44_1_C1_I16:
+ case Format_SR48_C1_I16:
+ return 1;
+ case Format_SR44_1_C2_I16:
+ case Format_SR48_C2_I16:
+ return 2;
+ case Format_Invalid:
+ default:
+ return 0;
+ }
+}
+
+NBAIO_Format Format_from_SR_C(unsigned sampleRate, unsigned channelCount)
+{
+ if (sampleRate == 44100 && channelCount == 2) return Format_SR44_1_C2_I16;
+ if (sampleRate == 48000 && channelCount == 2) return Format_SR48_C2_I16;
+ if (sampleRate == 44100 && channelCount == 1) return Format_SR44_1_C1_I16;
+ if (sampleRate == 48000 && channelCount == 1) return Format_SR48_C1_I16;
+ return Format_Invalid;
+}
+
+// This is a default implementation; it is expected that subclasses will optimize this.
+ssize_t NBAIO_Sink::writeVia(writeVia_t via, size_t total, void *user, size_t block)
+{
+ if (!mNegotiated) {
+ return (ssize_t) NEGOTIATE;
+ }
+ static const size_t maxBlock = 32;
+ size_t frameSize = Format_frameSize(mFormat);
+ ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
+ // double guarantees alignment for stack similar to what malloc() gives for heap
+ if (block == 0 || block > maxBlock) {
+ block = maxBlock;
+ }
+ double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
+ size_t accumulator = 0;
+ while (accumulator < total) {
+ size_t count = total - accumulator;
+ if (count > block) {
+ count = block;
+ }
+ ssize_t ret = via(user, buffer, count);
+ if (ret > 0) {
+ ALOG_ASSERT((size_t) ret <= count);
+ size_t maxRet = ret;
+ ret = write(buffer, maxRet);
+ if (ret > 0) {
+ ALOG_ASSERT((size_t) ret <= maxRet);
+ accumulator += ret;
+ continue;
+ }
+ }
+ return accumulator > 0 ? accumulator : ret;
+ }
+ return accumulator;
+}
+
+// This is a default implementation; it is expected that subclasses will optimize this.
+ssize_t NBAIO_Source::readVia(readVia_t via, size_t total, void *user, size_t block)
+{
+ if (!mNegotiated) {
+ return (ssize_t) NEGOTIATE;
+ }
+ static const size_t maxBlock = 32;
+ size_t frameSize = Format_frameSize(mFormat);
+ ALOG_ASSERT(frameSize > 0 && frameSize <= 8);
+ // double guarantees alignment for stack similar to what malloc() gives for heap
+ if (block == 0 || block > maxBlock) {
+ block = maxBlock;
+ }
+ double buffer[((frameSize * block) + sizeof(double) - 1) / sizeof(double)];
+ size_t accumulator = 0;
+ while (accumulator < total) {
+ size_t count = total - accumulator;
+ if (count > block) {
+ count = block;
+ }
+ ssize_t ret = read(buffer, count);
+ if (ret > 0) {
+ ALOG_ASSERT((size_t) ret <= count);
+ size_t maxRet = ret;
+ ret = via(user, buffer, maxRet);
+ if (ret > 0) {
+ ALOG_ASSERT((size_t) ret <= maxRet);
+ accumulator += ret;
+ continue;
+ }
+ }
+ return accumulator > 0 ? accumulator : ret;
+ }
+ return accumulator;
+}
+
+// Default implementation that only accepts my mFormat
+ssize_t NBAIO_Port::negotiate(const NBAIO_Format offers[], size_t numOffers,
+ NBAIO_Format counterOffers[], size_t& numCounterOffers)
+{
+ ALOGV("negotiate offers=%p numOffers=%u countersOffers=%p numCounterOffers=%u",
+ offers, numOffers, counterOffers, numCounterOffers);
+ if (mFormat != Format_Invalid) {
+ for (size_t i = 0; i < numOffers; ++i) {
+ if (offers[i] == mFormat) {
+ mNegotiated = true;
+ return i;
+ }
+ }
+ if (numCounterOffers > 0) {
+ counterOffers[0] = mFormat;
+ }
+ numCounterOffers = 1;
+ } else {
+ numCounterOffers = 0;
+ }
+ return (ssize_t) NEGOTIATE;
+}
+
+} // namespace android