diff options
| -rw-r--r-- | media/base/filters.h | 59 |
1 files changed, 24 insertions, 35 deletions
diff --git a/media/base/filters.h b/media/base/filters.h index 74220a4..e01c94c 100644 --- a/media/base/filters.h +++ b/media/base/filters.h @@ -2,12 +2,30 @@ // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. +// Filters are connected in a strongly typed manner, with downstream filters +// always reading data from upstream filters. Upstream filters have no clue +// who is actually reading from them, and return the results via OnAssignment +// using the AssignableInterface<SomeBufferType> interface: +// +// DemuxerStream(Video) <- VideoDecoder <- VideoRenderer +// DataSource <- Demuxer < +// DemuxerStream(Audio) <- AudioDecoder <- AudioRenderer +// +// Upstream -------------------------------------------------------> Downstream +// <- Reads flow this way +// Buffer assignments flow this way -> +// +// Every filter maintains a reference to the scheduler, who maintains data +// shared between filters (i.e., reference clock value, playback state). The +// scheduler is also responsible for scheduling filter tasks (i.e., a read on +// a VideoDecoder would result in scheduling a Decode task). Filters can also +// use the scheduler to signal errors and shutdown playback. + #ifndef MEDIA_BASE_FILTERS_H_ #define MEDIA_BASE_FILTERS_H_ #include <limits> #include <string> -#include "base/basictypes.h" #include "base/ref_counted.h" namespace media { @@ -34,44 +52,22 @@ enum FilterType { FILTER_MAX }; -// Filters are connected in a strongly typed manner, with downstream filters -// always reading data from upstream filters. Upstream filters have no clue -// who is actually reading from them, and return the results via OnAssignment -// using the AssignableInterface<SomeBufferType> interface: -// -// DemuxerStream(Video) <- VideoDecoder <- VideoRenderer -// DataSource <- Demuxer < -// DemuxerStream(Audio) <- AudioDecoder <- AudioRenderer -// -// Upstream -------------------------------------------------------> Downstream -// <- Reads flow this way -// Buffer assignments flow this way -> -// -// Every filter maintains a reference to the scheduler, who maintains data -// shared between filters (i.e., reference clock value, playback state). The -// scheduler is also responsible for scheduling filter tasks (i.e., a read on -// a VideoDecoder would result in scheduling a Decode task). Filters can also -// use the scheduler to signal errors and shutdown playback. - -// NOTE: this isn't a true interface since RefCountedThreadSafe has non-virtual -// members, therefore implementors should NOT subclass RefCountedThreadSafe. -// -// If you do, AddRef/Release will have different outcomes depending on the -// current type of the pointer (StreamSampleInterface vs. SomeImplementation) class MediaFilterInterface : public base::RefCountedThreadSafe<MediaFilterInterface> { public: - virtual ~MediaFilterInterface() {} - virtual void SetScheduler(SchedulerFilterInterface* scheduler) = 0; + + protected: + friend class base::RefCountedThreadSafe<MediaFilterInterface>; + virtual ~MediaFilterInterface() {} }; + class DataSourceInterface : public MediaFilterInterface { public: static const FilterType kFilterType = FILTER_DATA_SOURCE; static const size_t kReadError = static_cast<size_t>(-1); - virtual ~DataSourceInterface() {} // Initializes this filter, returns true if successful, false otherwise. virtual bool Initialize(const std::wstring& uri) = 0; @@ -99,7 +95,6 @@ class DataSourceInterface : public MediaFilterInterface { class DemuxerInterface : public MediaFilterInterface { public: static const FilterType kFilterType = FILTER_DEMUXER; - virtual ~DemuxerInterface() {} // Initializes this filter, returns true if successful, false otherwise. virtual bool Initialize(DataSourceInterface* data_source) = 0; @@ -114,8 +109,6 @@ class DemuxerInterface : public MediaFilterInterface { class DemuxerStreamInterface { public: - virtual ~DemuxerStreamInterface() {} - // Returns the MediaFormat for this filter. virtual const MediaFormat* GetMediaFormat() = 0; @@ -127,7 +120,6 @@ class DemuxerStreamInterface { class VideoDecoderInterface : public MediaFilterInterface { public: static const FilterType kFilterType = FILTER_VIDEO_DECODER; - virtual ~VideoDecoderInterface() {} // Initializes this filter, returns true if successful, false otherwise. virtual bool Initialize(DemuxerStreamInterface* demuxer_stream) = 0; @@ -143,7 +135,6 @@ class VideoDecoderInterface : public MediaFilterInterface { class AudioDecoderInterface : public MediaFilterInterface { public: static const FilterType kFilterType = FILTER_AUDIO_DECODER; - virtual ~AudioDecoderInterface() {} // Initializes this filter, returns true if successful, false otherwise. virtual bool Initialize(DemuxerStreamInterface* demuxer_stream) = 0; @@ -159,7 +150,6 @@ class AudioDecoderInterface : public MediaFilterInterface { class VideoRendererInterface : public MediaFilterInterface { public: static const FilterType kFilterType = FILTER_VIDEO_RENDERER; - virtual ~VideoRendererInterface() {} // Initializes this filter, returns true if successful, false otherwise. virtual bool Initialize(VideoDecoderInterface* decoder) = 0; @@ -169,7 +159,6 @@ class VideoRendererInterface : public MediaFilterInterface { class AudioRendererInterface : public MediaFilterInterface { public: static const FilterType kFilterType = FILTER_AUDIO_RENDERER; - virtual ~AudioRendererInterface() {} // Initializes this filter, returns true if successful, false otherwise. virtual bool Initialize(AudioDecoderInterface* decoder) = 0; |