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authorMatthew Hoops2015-09-28 21:22:01 -0400
committerJohannes Schickel2016-03-13 13:56:46 +0100
commit2ee85fcbd9a457d041436e4cdb600a2171ad0b1c (patch)
tree72bc233088270eb945eb684f49e5d62d34e95ddd /backends
parent91d695d4a2fea6742c31abd246a22c40797b014f (diff)
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BACKENDS: Use a threading for buffering Linux CD audio
Diffstat (limited to 'backends')
-rw-r--r--backends/audiocd/linux/linux-audiocd.cpp146
1 files changed, 125 insertions, 21 deletions
diff --git a/backends/audiocd/linux/linux-audiocd.cpp b/backends/audiocd/linux/linux-audiocd.cpp
index c079c2d744..917546cfa5 100644
--- a/backends/audiocd/linux/linux-audiocd.cpp
+++ b/backends/audiocd/linux/linux-audiocd.cpp
@@ -33,8 +33,11 @@
#include "backends/audiocd/default/default-audiocd.h"
#include "common/array.h"
#include "common/config-manager.h"
+#include "common/mutex.h"
+#include "common/queue.h"
#include "common/str.h"
#include "common/debug.h"
+#include "common/timer.h"
enum {
kLeadoutTrack = 0xAA
@@ -50,6 +53,11 @@ enum {
kFramesPerSecond = 75
};
+enum {
+ // Keep about a second's worth of audio in the buffer
+ kBufferThreshold = kFramesPerSecond
+};
+
static int getFrameCount(const cdrom_msf0 &msf) {
int time = msf.minute;
time *= kSecondsPerMinute;
@@ -62,6 +70,7 @@ static int getFrameCount(const cdrom_msf0 &msf) {
class LinuxAudioCDStream : public Audio::SeekableAudioStream {
public:
LinuxAudioCDStream(int fd, const cdrom_tocentry &startEntry, const cdrom_tocentry &endEntry);
+ ~LinuxAudioCDStream();
int readBuffer(int16 *buffer, const int numSamples);
bool isStereo() const { return true; }
@@ -76,10 +85,27 @@ private:
int16 _buffer[kSamplesPerFrame];
int _frame;
uint _bufferPos;
+
+ Common::Queue<int16 *> _bufferQueue;
+ int _bufferFrame;
+ Common::Mutex _mutex;
+
+ bool readNextFrame();
+ static void timerProc(void *refCon);
+ void onTimer();
+ void emptyQueue();
+ void startTimer();
+ void stopTimer();
};
LinuxAudioCDStream::LinuxAudioCDStream(int fd, const cdrom_tocentry &startEntry, const cdrom_tocentry &endEntry) :
- _fd(fd), _startEntry(startEntry), _endEntry(endEntry), _buffer(), _frame(0), _bufferPos(kSamplesPerFrame) {
+ _fd(fd), _startEntry(startEntry), _endEntry(endEntry), _buffer(), _frame(0), _bufferPos(kSamplesPerFrame), _bufferFrame(0) {
+ startTimer();
+}
+
+LinuxAudioCDStream::~LinuxAudioCDStream() {
+ stopTimer();
+ emptyQueue();
}
int LinuxAudioCDStream::readBuffer(int16 *buffer, const int numSamples) {
@@ -94,8 +120,90 @@ int LinuxAudioCDStream::readBuffer(int16 *buffer, const int numSamples) {
return samples;
while (samples < numSamples && !endOfData()) {
+ if (!readNextFrame())
+ return samples;
+
+ // Copy the samples over
+ for (_bufferPos = 0; _bufferPos < kSamplesPerFrame && samples < numSamples; )
+ buffer[samples++] = _buffer[_bufferPos++];
+ }
+
+ return samples;
+}
+
+bool LinuxAudioCDStream::readNextFrame() {
+ // Fetch a frame from the queue
+ int16 *buffer;
+
+ {
+ Common::StackLock lock(_mutex);
+
+ // Nothing we can do if it's empty
+ if (_bufferQueue.empty())
+ return false;
+
+ buffer = _bufferQueue.pop();
+ }
+
+ memcpy(_buffer, buffer, kSamplesPerFrame * 2);
+ delete[] buffer;
+ _frame++;
+ return true;
+}
+
+bool LinuxAudioCDStream::endOfData() const {
+ return getFrameCount(_startEntry.cdte_addr.msf) + _frame >= getFrameCount(_endEntry.cdte_addr.msf) && _bufferPos == kSamplesPerFrame;
+}
+
+bool LinuxAudioCDStream::seek(const Audio::Timestamp &where) {
+ // Stop the timer
+ stopTimer();
+
+ // Clear anything out of the queue
+ emptyQueue();
+
+ // Convert to the frame number
+ // Really not much else needed
+ _bufferPos = kSamplesPerFrame;
+ _frame = where.convertToFramerate(kFramesPerSecond).totalNumberOfFrames();
+ _bufferFrame = _frame;
+
+ // Start the timer again
+ startTimer();
+ return true;
+}
+
+Audio::Timestamp LinuxAudioCDStream::getLength() const {
+ return Audio::Timestamp(0, getFrameCount(_endEntry.cdte_addr.msf) - getFrameCount(_startEntry.cdte_addr.msf), 75);
+}
+
+void LinuxAudioCDStream::timerProc(void *refCon) {
+ static_cast<LinuxAudioCDStream *>(refCon)->onTimer();
+}
+
+void LinuxAudioCDStream::onTimer() {
+ // The goal here is to do as much work in this timer instead
+ // of doing it in the readBuffer() call, which is the mixer.
+
+ // If we're done, bail.
+ if (getFrameCount(_startEntry.cdte_addr.msf) + _bufferFrame >= getFrameCount(_endEntry.cdte_addr.msf))
+ return;
+
+ // Get a quick count of the number of items in the queue
+ // We don't care that much; we only need a quick estimate
+ _mutex.lock();
+ uint32 queueCount = _bufferQueue.size();
+ _mutex.unlock();
+
+ // If we have enough audio buffered, bail out
+ if (queueCount >= kBufferThreshold)
+ return;
+
+ while (queueCount < kBufferThreshold && getFrameCount(_startEntry.cdte_addr.msf) + _bufferFrame < getFrameCount(_endEntry.cdte_addr.msf)) {
+ int16 *buffer = new int16[kSamplesPerFrame];
+
// Figure out the MSF of the frame we're looking for
- int frame = _frame + getFrameCount(_startEntry.cdte_addr.msf);
+ int frame = _bufferFrame + getFrameCount(_startEntry.cdte_addr.msf);
int seconds = frame / kFramesPerSecond;
frame %= kFramesPerSecond;
@@ -109,38 +217,34 @@ int LinuxAudioCDStream::readBuffer(int16 *buffer, const int numSamples) {
readAudio.addr.msf.frame = frame;
readAudio.addr_format = CDROM_MSF;
readAudio.nframes = 1;
- readAudio.buf = reinterpret_cast<__u8*>(_buffer);
+ readAudio.buf = reinterpret_cast<__u8*>(buffer);
if (ioctl(_fd, CDROMREADAUDIO, &readAudio) < 0) {
warning("Failed to read audio");
- _frame = getFrameCount(_endEntry.cdte_addr.msf);
- return samples;
+ _bufferFrame = getFrameCount(_endEntry.cdte_addr.msf);
+ return;
}
- _frame++;
+ _bufferFrame++;
- // Copy the samples over
- for (_bufferPos = 0; _bufferPos < kSamplesPerFrame && samples < numSamples; )
- buffer[samples++] = _buffer[_bufferPos++];
+ // Now push the buffer onto the queue
+ Common::StackLock lock(_mutex);
+ _bufferQueue.push(buffer);
+ queueCount = _bufferQueue.size();
}
-
- return samples;
}
-bool LinuxAudioCDStream::endOfData() const {
- return getFrameCount(_startEntry.cdte_addr.msf) + _frame >= getFrameCount(_endEntry.cdte_addr.msf) && _bufferPos == kSamplesPerFrame;
+void LinuxAudioCDStream::startTimer() {
+ g_system->getTimerManager()->installTimerProc(timerProc, 10 * 1000, this, "LinuxAudioCDStream");
}
-bool LinuxAudioCDStream::seek(const Audio::Timestamp &where) {
- // Convert to the frame number
- // Really not much else needed
- _bufferPos = kSamplesPerFrame;
- _frame = where.convertToFramerate(kFramesPerSecond).totalNumberOfFrames();
- return true;
+void LinuxAudioCDStream::stopTimer() {
+ g_system->getTimerManager()->removeTimerProc(timerProc);
}
-Audio::Timestamp LinuxAudioCDStream::getLength() const {
- return Audio::Timestamp(0, getFrameCount(_endEntry.cdte_addr.msf) - getFrameCount(_startEntry.cdte_addr.msf), 75);
+void LinuxAudioCDStream::emptyQueue() {
+ while (!_bufferQueue.empty())
+ delete[] _bufferQueue.pop();
}
class LinuxAudioCDManager : public DefaultAudioCDManager {