From f8edbfe65440706c0508b634f3ccc7b146ee7348 Mon Sep 17 00:00:00 2001 From: "cpu@google.com" Date: Mon, 5 Jan 2009 20:37:11 +0000 Subject: A simple tone source useful for testing and troubleshooting - Only windows 16 PCM mono implementation so far. Review URL: http://codereview.chromium.org/16226 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@7557 0039d316-1c4b-4281-b951-d872f2087c98 --- media/audio/win/simple_sources_win.cc | 43 +++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 media/audio/win/simple_sources_win.cc (limited to 'media/audio/win') diff --git a/media/audio/win/simple_sources_win.cc b/media/audio/win/simple_sources_win.cc new file mode 100644 index 0000000..b6fda23 --- /dev/null +++ b/media/audio/win/simple_sources_win.cc @@ -0,0 +1,43 @@ +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#include + +#include "base/basictypes.h" +#include "base/logging.h" +#include "media/audio/audio_output.h" +#include "media/audio/simple_sources.h" + +SineWaveAudioSource::SineWaveAudioSource(Format format, int channels, + double freq, double sample_freq) + : format_(format), + channels_(channels), + freq_(freq), + sample_freq_(sample_freq) { + // TODO(cpu): support other formats. + DCHECK((format_ == FORMAT_16BIT_LINEAR_PCM) && (channels_ == 1)); +} + +// The implementation could be more efficient if a lookup table is constructed +// but it is efficient enough for our simple needs. +size_t SineWaveAudioSource::OnMoreData(AudioOutputStream* stream, + void* dest, size_t max_size) { + const double kTwoPi = 2.0 * 3.141592653589; + double f = freq_ / sample_freq_; + int16* sin_tbl = reinterpret_cast(dest); + size_t len = max_size / sizeof(int16); + // The table is filled with s(t) = 32768*sin(2PI*f*t). + for (size_t ix = 0; ix != len; ++ix) { + double th = kTwoPi * ix * f; + sin_tbl[ix] = static_cast((1 << 15) * sin(th)); + } + return max_size; +} + +void SineWaveAudioSource::OnClose(AudioOutputStream* stream) { +} + +void SineWaveAudioSource::OnError(AudioOutputStream* stream, int code) { + NOTREACHED(); +} -- cgit v1.1