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// Copyright 2015 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_GPU_ACCELERATED_VIDEO_DECODER_H_
#define MEDIA_GPU_ACCELERATED_VIDEO_DECODER_H_
#include <stddef.h>
#include <stdint.h>
#include "base/macros.h"
#include "media/base/decoder_buffer.h"
#include "media/base/video_codecs.h"
#include "media/gpu/media_gpu_export.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"
namespace media {
// An AcceleratedVideoDecoder is a video decoder that requires support from an
// external accelerator (typically a hardware accelerator) to partially offload
// the decode process after parsing stream headers, and performing reference
// frame and state management.
class MEDIA_GPU_EXPORT AcceleratedVideoDecoder {
public:
AcceleratedVideoDecoder() {}
virtual ~AcceleratedVideoDecoder() {}
// Set the buffer owned by |decoder_buffer| as the current source of encoded
// stream data. AcceleratedVideoDecoder doesn't have an ownership of the
// buffer. |decoder_buffer| must be kept alive until Decode() returns
// kRanOutOfStreamData. Pictures produced as a result of this call should be
// assigned the passed stream |id|.
virtual void SetStream(int32_t id, const DecoderBuffer& decoder_buffer) = 0;
// Have the decoder flush its state and trigger output of all previously
// decoded surfaces. Return false on failure.
virtual bool Flush() WARN_UNUSED_RESULT = 0;
// Stop (pause) decoding, discarding all remaining inputs and outputs,
// but do not flush decoder state, so that playback can be resumed later,
// possibly from a different location.
// To be called during decoding.
virtual void Reset() = 0;
enum DecodeResult {
kDecodeError, // Error while decoding.
// TODO(posciak): unsupported streams are currently treated as error
// in decoding; in future it could perhaps be possible to fall back
// to software decoding instead.
// kStreamError, // Error in stream.
kConfigChange, // This is returned when some configuration (e.g.
// profile or picture size) is changed. A client may
// need to apply the client side the configuration
// properly (e.g. allocate buffers with the new
// resolution).
kRanOutOfStreamData, // Need more stream data to proceed.
kRanOutOfSurfaces, // Waiting for the client to free up output surfaces.
kNeedContextUpdate, // Waiting for the client to update decoding context
// with data acquired from the accelerator.
kTryAgain, // The accelerator needs additional data (independently
// provided) in order to proceed. This may be a new key in order to decrypt
// encrypted data, or existing hardware resources freed so that they can be
// reused. Decoding can resume once the data has been provided.
};
// Try to decode more of the stream, returning decoded frames asynchronously.
// Return when more stream is needed, when we run out of free surfaces, when
// we need a new set of them, or when an error occurs.
virtual DecodeResult Decode() WARN_UNUSED_RESULT = 0;
// Return dimensions/visible rectangle/profile/required number of pictures
// that client should be ready to provide for the decoder to function properly
// (of which up to GetNumReferenceFrames() might be needed for internal
// decoding). To be used after Decode() returns kConfigChange.
virtual gfx::Size GetPicSize() const = 0;
virtual gfx::Rect GetVisibleRect() const = 0;
virtual VideoCodecProfile GetProfile() const = 0;
virtual size_t GetRequiredNumOfPictures() const = 0;
virtual size_t GetNumReferenceFrames() const = 0;
// About 3 secs for 30 fps video. When the new sized keyframe is missed, the
// decoder cannot decode the frame. The number of frames are skipped until
// getting new keyframe. If dropping more than the number of frames, the
// decoder reports decode error, which may take longer time to recover it.
// The number is the sweet spot which the decoder can tolerate to handle the
// missing keyframe by itself. In addition, this situation is exceptional.
static constexpr size_t kVPxMaxNumOfSizeChangeFailures = 75;
private:
DISALLOW_COPY_AND_ASSIGN(AcceleratedVideoDecoder);
};
} // namespace media
#endif // MEDIA_GPU_ACCELERATED_VIDEO_DECODER_H_
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