1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef MEDIA_BASE_RENDERER_H_
6 #define MEDIA_BASE_RENDERER_H_
8 #include "base/callback.h"
9 #include "base/macros.h"
10 #include "base/memory/ref_counted.h"
11 #include "base/optional.h"
12 #include "base/time/time.h"
13 #include "media/base/buffering_state.h"
14 #include "media/base/demuxer_stream.h"
15 #include "media/base/media_export.h"
16 #include "media/base/pipeline_status.h"
24 class MEDIA_EXPORT Renderer {
28 // Stops rendering and fires any pending callbacks.
31 // Initializes the Renderer with |media_resource|, executing |init_cb| upon
32 // completion. |media_resource| must be valid for the lifetime of the Renderer
33 // object. |init_cb| must only be run after this method has returned. Firing
34 // |init_cb| may result in the immediate destruction of the caller, so it must
35 // be run only prior to returning.
36 virtual void Initialize(MediaResource* media_resource,
37 RendererClient* client,
38 PipelineStatusCallback init_cb) = 0;
40 // Associates the |cdm_context| with this Renderer for decryption (and
41 // decoding) of media data, then fires |cdm_attached_cb| with whether the
42 // operation succeeded.
43 using CdmAttachedCB = base::OnceCallback<void(bool)>;
44 virtual void SetCdm(CdmContext* cdm_context, CdmAttachedCB cdm_attached_cb);
46 // Specifies a latency hint from the site. Renderers should clamp the hint
47 // value to reasonable min and max and use the resulting value as a target
48 // latency such that the buffering state reaches HAVE_ENOUGH when this amount
49 // of decoded data is buffered. A nullopt hint indicates the user is clearing
50 // their preference and the renderer should restore its default buffering
52 virtual void SetLatencyHint(base::Optional<base::TimeDelta> latency_hint) = 0;
54 // Sets whether pitch adjustment should be applied when the playback rate is
55 // different than 1.0.
56 virtual void SetPreservesPitch(bool preserves_pitch);
58 // The following functions must be called after Initialize().
60 // Discards any buffered data, executing |flush_cb| when completed.
61 virtual void Flush(base::OnceClosure flush_cb) = 0;
63 // Starts rendering from |time|.
64 virtual void StartPlayingFrom(base::TimeDelta time) = 0;
66 // Updates the current playback rate. The default playback rate should be 0.
67 virtual void SetPlaybackRate(double playback_rate) = 0;
69 // Sets the output volume. The default volume should be 1.
70 virtual void SetVolume(float volume) = 0;
72 // Returns the current media time.
74 // This method must be safe to call from any thread.
75 virtual base::TimeDelta GetMediaTime() = 0;
77 // Provides a list of DemuxerStreams correlating to the tracks which should
78 // be played. An empty list would mean that any playing track of the same
79 // type should be flushed and disabled. Any provided Streams should be played
80 // by whatever mechanism the subclass of Renderer choses for managing it's AV
82 virtual void OnSelectedVideoTracksChanged(
83 const std::vector<DemuxerStream*>& enabled_tracks,
84 base::OnceClosure change_completed_cb);
85 virtual void OnEnabledAudioTracksChanged(
86 const std::vector<DemuxerStream*>& enabled_tracks,
87 base::OnceClosure change_completed_cb);
90 DISALLOW_COPY_AND_ASSIGN(Renderer);
95 #endif // MEDIA_BASE_RENDERER_H_