| // Copyright (c) 2012 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. |
| |
| #ifndef MEDIA_BASE_VIDEO_DECODER_H_ |
| #define MEDIA_BASE_VIDEO_DECODER_H_ |
| |
| #include <string> |
| |
| #include "base/callback.h" |
| #include "base/memory/ref_counted.h" |
| #include "media/base/media_export.h" |
| #include "media/base/pipeline_status.h" |
| #include "ui/gfx/size.h" |
| |
| namespace media { |
| |
| class DecoderBuffer; |
| class VideoDecoderConfig; |
| class VideoFrame; |
| |
| class MEDIA_EXPORT VideoDecoder { |
| public: |
| // Status codes for decode operations on VideoDecoder. |
| // TODO(rileya): Now that both AudioDecoder and VideoDecoder Status enums |
| // match, break them into a decoder_status.h. |
| enum Status { |
| kOk, // Everything went as planned. |
| kAborted, // Decode was aborted as a result of Reset() being called. |
| kDecodeError, // Decoding error happened. |
| kDecryptError // Decrypting error happened. |
| }; |
| |
| // Callback for VideoDecoder to return a decoded frame whenever it becomes |
| // available. Only non-EOS frames should be returned via this callback. |
| typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> OutputCB; |
| |
| // Callback type for Decode(). Called after the decoder has completed decoding |
| // corresponding DecoderBuffer, indicating that it's ready to accept another |
| // buffer to decode. |
| typedef base::Callback<void(Status status)> DecodeCB; |
| |
| VideoDecoder(); |
| |
| // Fires any pending callbacks, stops and destroys the decoder. |
| // Note: Since this is a destructor, |this| will be destroyed after this call. |
| // Make sure the callbacks fired from this call doesn't post any task that |
| // depends on |this|. |
| virtual ~VideoDecoder(); |
| |
| // Returns the name of the decoder for logging purpose. |
| virtual std::string GetDisplayName() const = 0; |
| |
| // Initializes a VideoDecoder with the given |config|, executing the |
| // |status_cb| upon completion. |output_cb| is called for each output frame |
| // decoded by Decode(). |
| // |
| // Note: |
| // 1) The VideoDecoder will be reinitialized if it was initialized before. |
| // Upon reinitialization, all internal buffered frames will be dropped. |
| // 2) This method should not be called during pending decode or reset. |
| // 3) No VideoDecoder calls should be made before |status_cb| is executed. |
| virtual void Initialize(const VideoDecoderConfig& config, |
| bool low_delay, |
| const PipelineStatusCB& status_cb, |
| const OutputCB& output_cb) = 0; |
| |
| // Requests a |buffer| to be decoded. The status of the decoder and decoded |
| // frame are returned via the provided callback. Some decoders may allow |
| // decoding multiple buffers in parallel. Callers should call |
| // GetMaxDecodeRequests() to get number of buffers that may be decoded in |
| // parallel. Decoder must call |decode_cb| in the same order in which Decode() |
| // is called. |
| // |
| // Implementations guarantee that the callback will not be called from within |
| // this method and that |decode_cb| will not be blocked on the following |
| // Decode() calls (i.e. |decode_cb| will be called even if Decode() is never |
| // called again). |
| // |
| // After decoding is finished the decoder calls |output_cb| specified in |
| // Initialize() for each decoded frame. |output_cb| may be called before or |
| // after |decode_cb|. |
| // |
| // If |buffer| is an EOS buffer then the decoder must be flushed, i.e. |
| // |output_cb| must be called for each frame pending in the queue and |
| // |decode_cb| must be called after that. Callers will not call Decode() |
| // again until after the flush completes. |
| virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer, |
| const DecodeCB& decode_cb) = 0; |
| |
| // Resets decoder state. All pending Decode() requests will be finished or |
| // aborted before |closure| is called. |
| // Note: No VideoDecoder calls should be made before |closure| is executed. |
| virtual void Reset(const base::Closure& closure) = 0; |
| |
| // Returns true if the decoder needs bitstream conversion before decoding. |
| virtual bool NeedsBitstreamConversion() const; |
| |
| // Returns true if the decoder currently has the ability to decode and return |
| // a VideoFrame. Most implementations can allocate a new VideoFrame and hence |
| // this will always return true. Override and return false for decoders that |
| // use a fixed set of VideoFrames for decoding. |
| virtual bool CanReadWithoutStalling() const; |
| |
| // Returns maximum number of parallel decode requests. |
| virtual int GetMaxDecodeRequests() const; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(VideoDecoder); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_VIDEO_DECODER_H_ |