From aeb67506173a7b8cef089fa725c3abe1f629dc67 Mon Sep 17 00:00:00 2001 From: Scott Murray Date: Sun, 2 Apr 2017 12:49:28 -0400 Subject: Switch to using Qt's QAudioOutput for output The underlying issue in the hang reported in SPEC-455 is that due to the synchronous nature of the pa_simple_* PulseAudio API, the pa_simple_write call used blocks when a stream is corked . That prevents the tuner plugin's output thread from exiting when playback is stopped, resulting in the observed hang. After examining the available options, it seemed like switching to Qt's QAudioOutput class made sense since it allows using the asynchronous PulseAudio API easily, and like the QRadio class the tuner plugin implements, it is part of QtMultimedia itself. Note that the radio_output.* files have been removed as the code is no longer used, and a new pair of OutputBuffer source files have been added to contain the small class that is used to connect the RTL-SDR output to QAudioOutput. Bug-AGL: SPEC-455 Change-Id: I0d690143b9c70fdca24f9fbf3b016feef8ae627b Signed-off-by: Scott Murray --- OutputBuffer.cpp | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 OutputBuffer.cpp (limited to 'OutputBuffer.cpp') diff --git a/OutputBuffer.cpp b/OutputBuffer.cpp new file mode 100644 index 0000000..c6fe30a --- /dev/null +++ b/OutputBuffer.cpp @@ -0,0 +1,59 @@ +/* + * Copyright (C) 2017 Konsulko Group + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#include + +OutputBuffer::OutputBuffer(const QAudioFormat &format, QObject *parent) + : QIODevice(parent) +{ + m_sample_size = format.bytesPerFrame(); +} + +OutputBuffer::~OutputBuffer() +{ +} + +void OutputBuffer::start() +{ + open(QIODevice::ReadWrite); +} + +void OutputBuffer::stop() +{ + close(); + QMutexLocker locker(&m_mutex); + m_buffer.clear(); +} + +qint64 OutputBuffer::readData(char *data, qint64 len) +{ + QMutexLocker locker(&m_mutex); + int n = qMin((qint64) m_buffer.size(), len); + + // Make sure reads are in units of the sample size + n = n - (n % m_sample_size); + + if (!m_buffer.isEmpty()) { + memcpy(data, m_buffer.constData(), n); + m_buffer.remove(0, n); + } + return n; +} + +qint64 OutputBuffer::writeData(const char *data, qint64 len) +{ + QMutexLocker locker(&m_mutex); + m_buffer.append(data, len); + return len; +} + +qint64 OutputBuffer::bytesAvailable() +{ + QMutexLocker locker(&m_mutex); + return m_buffer.size() + QIODevice::bytesAvailable(); +} -- cgit 1.2.3-korg