| // 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 "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. |
| enum Status { |
| kOk, // Everything went as planned. |
| kNotEnoughData, // Not enough data to produce a video frame. |
| kDecodeError, // Decoding error happened. |
| kDecryptError // Decrypting error happened. |
| }; |
| |
| VideoDecoder(); |
| virtual ~VideoDecoder(); |
| |
| // Initializes a VideoDecoder with the given |config|, executing the |
| // |status_cb| upon completion. |
| // |
| // 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, reset or stop. |
| // 3) No VideoDecoder calls except for Stop() should be made before |
| // |status_cb| is executed. |
| virtual void Initialize(const VideoDecoderConfig& config, |
| const PipelineStatusCB& status_cb) = 0; |
| |
| // Requests a |buffer| to be decoded. The status of the decoder and decoded |
| // frame are returned via the provided callback. Only one decode may be in |
| // flight at any given time. |
| // |
| // Implementations guarantee that the callback will not be called from within |
| // this method. |
| // |
| // If the returned status is kOk: |
| // - Non-EOS (end of stream) frame contains decoded video data. |
| // - EOS frame indicates the end of the stream. |
| // - NULL frame indicates an aborted decode. This can happen if Reset() or |
| // Stop() is called during the decoding process. |
| // Otherwise the returned frame must be NULL. |
| typedef base::Callback<void(Status, |
| const scoped_refptr<VideoFrame>&)> DecodeCB; |
| virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer, |
| const DecodeCB& decode_cb) = 0; |
| |
| // Resets decoder state, fulfilling all pending DecodeCB and dropping extra |
| // queued decoded data. After this call, the decoder is back to an initialized |
| // clean state. |
| // Note: No VideoDecoder calls should be made before |closure| is executed. |
| virtual void Reset(const base::Closure& closure) = 0; |
| |
| // Stops decoder, fires any pending callbacks and sets the decoder to an |
| // uninitialized state. A VideoDecoder cannot be re-initialized after it has |
| // been stopped. |
| // Note that if Initialize() has been called, Stop() must be called and |
| // complete before deleting the decoder. |
| virtual void Stop(const base::Closure& closure) = 0; |
| |
| // Returns true if the output format has an alpha channel. Most formats do not |
| // have alpha so the default is false. Override and return true for decoders |
| // that return formats with an alpha channel. |
| virtual bool HasAlpha() const; |
| |
| // 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; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(VideoDecoder); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_VIDEO_DECODER_H_ |