1 // Copyright (c) 2012 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_VIDEO_DECODER_H_
6 #define MEDIA_BASE_VIDEO_DECODER_H_
10 #include "base/callback.h"
11 #include "base/memory/ref_counted.h"
12 #include "media/base/media_export.h"
13 #include "media/base/pipeline_status.h"
14 #include "ui/gfx/size.h"
19 class VideoDecoderConfig;
22 class MEDIA_EXPORT VideoDecoder {
24 // Status codes for decode operations on VideoDecoder.
25 // TODO(rileya): Now that both AudioDecoder and VideoDecoder Status enums
26 // match, break them into a decoder_status.h.
28 kOk, // Everything went as planned.
29 kAborted, // Decode was aborted as a result of Reset() being called.
30 kDecodeError, // Decoding error happened.
31 kDecryptError // Decrypting error happened.
34 // Callback for VideoDecoder to return a decoded frame whenever it becomes
35 // available. Only non-EOS frames should be returned via this callback.
36 typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> OutputCB;
38 // Callback type for Decode(). Called after the decoder has completed decoding
39 // corresponding DecoderBuffer, indicating that it's ready to accept another
41 typedef base::Callback<void(Status status)> DecodeCB;
45 // Fires any pending callbacks, stops and destroys the decoder.
46 // Note: Since this is a destructor, |this| will be destroyed after this call.
47 // Make sure the callbacks fired from this call doesn't post any task that
49 virtual ~VideoDecoder();
51 // Returns the name of the decoder for logging purpose.
52 virtual std::string GetDisplayName() const = 0;
54 // Initializes a VideoDecoder with the given |config|, executing the
55 // |status_cb| upon completion. |output_cb| is called for each output frame
56 // decoded by Decode().
59 // 1) The VideoDecoder will be reinitialized if it was initialized before.
60 // Upon reinitialization, all internal buffered frames will be dropped.
61 // 2) This method should not be called during pending decode or reset.
62 // 3) No VideoDecoder calls should be made before |status_cb| is executed.
63 virtual void Initialize(const VideoDecoderConfig& config,
65 const PipelineStatusCB& status_cb,
66 const OutputCB& output_cb) = 0;
68 // Requests a |buffer| to be decoded. The status of the decoder and decoded
69 // frame are returned via the provided callback. Some decoders may allow
70 // decoding multiple buffers in parallel. Callers should call
71 // GetMaxDecodeRequests() to get number of buffers that may be decoded in
72 // parallel. Decoder must call |decode_cb| in the same order in which Decode()
75 // Implementations guarantee that the callback will not be called from within
76 // this method and that |decode_cb| will not be blocked on the following
77 // Decode() calls (i.e. |decode_cb| will be called even if Decode() is never
80 // After decoding is finished the decoder calls |output_cb| specified in
81 // Initialize() for each decoded frame. |output_cb| may be called before or
84 // If |buffer| is an EOS buffer then the decoder must be flushed, i.e.
85 // |output_cb| must be called for each frame pending in the queue and
86 // |decode_cb| must be called after that. Callers will not call Decode()
87 // again until after the flush completes.
88 virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
89 const DecodeCB& decode_cb) = 0;
91 // Resets decoder state. All pending Decode() requests will be finished or
92 // aborted before |closure| is called.
93 // Note: No VideoDecoder calls should be made before |closure| is executed.
94 virtual void Reset(const base::Closure& closure) = 0;
96 // Returns true if the decoder needs bitstream conversion before decoding.
97 virtual bool NeedsBitstreamConversion() const;
99 // Returns true if the decoder currently has the ability to decode and return
100 // a VideoFrame. Most implementations can allocate a new VideoFrame and hence
101 // this will always return true. Override and return false for decoders that
102 // use a fixed set of VideoFrames for decoding.
103 virtual bool CanReadWithoutStalling() const;
105 // Returns maximum number of parallel decode requests.
106 virtual int GetMaxDecodeRequests() const;
109 DISALLOW_COPY_AND_ASSIGN(VideoDecoder);
114 #endif // MEDIA_BASE_VIDEO_DECODER_H_