зеркало из https://github.com/mozilla/gecko-dev.git
109 строки
4.0 KiB
C++
109 строки
4.0 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#if !defined(DirectShowReader_h_)
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#define DirectShowReader_h_
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#include "windows.h" // HRESULT, DWORD
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#include "MediaDecoderReader.h"
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#include "MediaResource.h"
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#include "mozilla/RefPtr.h"
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#include "MP3FrameParser.h"
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// Add the graph to the Running Object Table so that we can connect
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// to this graph with GraphEdit/GraphStudio. Note: on Vista and up you must
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// also regsvr32 proppage.dll from the Windows SDK.
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// See: http://msdn.microsoft.com/en-us/library/ms787252(VS.85).aspx
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// #define DIRECTSHOW_REGISTER_GRAPH
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struct IGraphBuilder;
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struct IMediaControl;
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struct IMediaSeeking;
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namespace mozilla {
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class AudioSinkFilter;
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class SourceFilter;
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// Decoder backend for decoding MP3 using DirectShow. DirectShow operates as
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// a filter graph. The basic design of the DirectShowReader is that we have
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// a SourceFilter that wraps the MediaResource that connects to the
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// MP3 decoder filter. The MP3 decoder filter "pulls" data as it requires it
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// downstream on its own thread. When the MP3 decoder has produced a block of
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// decoded samples, its thread calls downstream into our AudioSinkFilter,
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// passing the decoded buffer in. The AudioSinkFilter inserts the samples into
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// a SampleSink object. The SampleSink blocks the MP3 decoder's thread until
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// the decode thread calls DecodeAudioData(), whereupon the SampleSink
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// releases the decoded samples to the decode thread, and unblocks the MP3
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// decoder's thread. The MP3 decoder can then request more data from the
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// SourceFilter, and decode more data. If the decode thread calls
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// DecodeAudioData() and there's no decoded samples waiting to be extracted
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// in the SampleSink, the SampleSink blocks the decode thread until the MP3
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// decoder produces a decoded sample.
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class DirectShowReader : public MediaDecoderReader
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{
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public:
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DirectShowReader(AbstractMediaDecoder* aDecoder);
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virtual ~DirectShowReader();
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bool DecodeAudioData() override;
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bool DecodeVideoFrame(bool &aKeyframeSkip,
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int64_t aTimeThreshold) override;
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nsresult ReadMetadata(MediaInfo* aInfo,
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MetadataTags** aTags) override;
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RefPtr<SeekPromise>
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Seek(SeekTarget aTarget, int64_t aEndTime) override;
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private:
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// Notifies the filter graph that playback is complete. aStatus is
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// the code to send to the filter graph. Always returns false, so
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// that we can just "return Finish()" from DecodeAudioData().
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bool Finish(HRESULT aStatus);
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nsresult SeekInternal(int64_t aTime);
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// DirectShow filter graph, and associated playback and seeking
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// control interfaces.
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RefPtr<IGraphBuilder> mGraph;
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RefPtr<IMediaControl> mControl;
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RefPtr<IMediaSeeking> mMediaSeeking;
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// Wraps the MediaResource, and feeds undecoded data into the filter graph.
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RefPtr<SourceFilter> mSourceFilter;
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// Sits at the end of the graph, removing decoded samples from the graph.
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// The graph will block while this is blocked, i.e. it will pause decoding.
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RefPtr<AudioSinkFilter> mAudioSinkFilter;
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// Some MP3s are variable bitrate, so DirectShow's duration estimation
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// can make its duration estimation based on the wrong bitrate. So we parse
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// the MP3 frames to get a more accuate estimate of the duration.
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MP3FrameParser mMP3FrameParser;
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#ifdef DIRECTSHOW_REGISTER_GRAPH
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// Used to add/remove the filter graph to the Running Object Table. You can
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// connect GraphEdit/GraphStudio to the graph to observe and/or debug its
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// topology and state.
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DWORD mRotRegister;
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#endif
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// Number of channels in the audio stream.
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uint32_t mNumChannels;
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// Samples per second in the audio stream.
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uint32_t mAudioRate;
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// Number of bytes per sample. Can be either 1 or 2.
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uint32_t mBytesPerSample;
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};
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} // namespace mozilla
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#endif
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