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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.
#include <stddef.h>
#include <stdint.h>
#include "base/macros.h"
#include "media/base/decrypt_config.h"
#include "media/gpu/media_gpu_export.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 {
AcceleratedVideoDecoder() {}
virtual ~AcceleratedVideoDecoder() {}
// Set the buffer at |ptr| of |size| bytes as the current source of encoded
// stream data. Pictures produced as a result of this call should be assigned
// the passed stream |id|. |decrypt_config| may specify the decryption
// configuration of the specified buffer, and in that case, Decode() may
// return kNoKey.
virtual void SetStream(int32_t id,
const uint8_t* ptr,
size_t size,
const DecryptConfig* decrypt_config = nullptr) = 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.
kAllocateNewSurfaces, // Need a new set of surfaces to be allocated.
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/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 kAllocateNewSurfaces.
virtual gfx::Size GetPicSize() 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;
} // namespace media