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// Copyright (c) 2014 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 PPAPI_CPP_VIDEO_DECODER_H_
#define PPAPI_CPP_VIDEO_DECODER_H_
#include "ppapi/c/pp_codecs.h"
#include "ppapi/c/pp_size.h"
#include "ppapi/cpp/completion_callback.h"
#include "ppapi/cpp/graphics_3d.h"
#include "ppapi/cpp/resource.h"
#include "ppapi/cpp/size.h"
/// @file
/// This file defines the API to create and use a VideoDecoder resource.
struct PP_FileInfo;
namespace pp {
class InstanceHandle;
/// Video decoder interface.
///
/// Typical usage:
/// - Call Create() to create a new video decoder resource.
/// - Call Initialize() to initialize it with a 3d graphics context and the
/// desired codec profile.
/// - Call Decode() continuously (waiting for each previous call to complete) to
/// push bitstream buffers to the decoder.
/// - Call GetPicture() continuously (waiting for each previous call to
/// complete) to pull decoded pictures from the decoder.
/// - Call Flush() to signal end of stream to the decoder and perform shutdown
/// when it completes.
/// - Call Reset() to quickly stop the decoder (e.g. to implement Seek) and wait
/// for the callback before restarting decoding at another point.
/// - To destroy the decoder, the plugin should release all of its references to
/// it. Any pending callbacks will abort before the decoder is destroyed.
///
/// Available video codecs vary by platform.
/// All: theora, vorbis, vp8.
/// Chrome and ChromeOS: aac, h264.
/// ChromeOS: mpeg4.
class VideoDecoder : public Resource {
public:
/// Default constructor for creating an is_null() <code>VideoDecoder</code>
/// object.
VideoDecoder();
/// A constructor used to create a <code>VideoDecoder</code> and associate it
/// with the provided <code>Instance</code>.
/// @param[in] instance The instance with which this resource will be
/// associated.
explicit VideoDecoder(const InstanceHandle& instance);
/// The copy constructor for <code>VideoDecoder</code>.
/// @param[in] other A reference to a <code>VideoDecoder</code>.
VideoDecoder(const VideoDecoder& other);
/// Initializes a video decoder resource. This should be called after Create()
/// and before any other functions.
///
/// @param[in] graphics3d_context A <code>PPB_Graphics3D</code> resource to
/// use during decoding.
/// @param[in] profile A <code>PP_VideoProfile</code> specifying the video
/// codec profile.
/// @param[in] acceleration A <code>PP_HardwareAcceleration</code> specifying
/// whether to use a hardware accelerated or a software implementation.
/// @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
/// completion.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_NOTSUPPORTED if video decoding is not available, or the
/// requested profile is not supported. In this case, the client may call
/// Initialize() again with different parameters to find a good configuration.
int32_t Initialize(const Graphics3D& graphics3d_context,
PP_VideoProfile profile,
PP_HardwareAcceleration acceleration,
const CompletionCallback& callback);
/// Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
/// |buffer|. The plugin should wait until the decoder signals completion by
/// returning PP_OK or by running |callback| before calling Decode() again.
///
/// In general, each bitstream buffer should contain a demuxed bitstream frame
/// for the selected video codec. For example, H264 decoders expect to receive
/// one AnnexB NAL unit, including the 4 byte start code prefix, while VP8
/// decoders expect to receive a bitstream frame without the IVF frame header.
///
/// If the call to Decode() eventually results in a picture, the |decode_id|
/// parameter is copied into the returned picture. The plugin can use this to
/// associate decoded pictures with Decode() calls (e.g. to assign timestamps
/// or frame numbers to pictures.) This value is opaque to the API so the
/// plugin is free to pass any value.
///
/// @param[in] decode_id An optional value, chosen by the plugin, that can be
/// used to associate calls to Decode() with decoded pictures returned by
/// GetPicture().
/// @param[in] size Buffer size in bytes.
/// @param[in] buffer Starting address of buffer.
/// @param[in] callback A <code>CompletionCallback</code> to be called on
/// completion.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Flush()
/// or Reset() call is pending.
/// Returns PP_ERROR_INPROGRESS if there is another Decode() call pending.
/// Returns PP_ERROR_NOMEMORY if a bitstream buffer can't be created.
/// Returns PP_ERROR_ABORTED when Reset() is called while Decode() is pending.
int32_t Decode(uint32_t decode_id,
uint32_t size,
const void* buffer,
const CompletionCallback& callback);
/// Gets the next picture from the decoder. The picture is valid after the
/// decoder signals completion by returning PP_OK or running |callback|. The
/// plugin can call GetPicture() again after the decoder signals completion.
/// When the plugin is finished using the picture, it should return it to the
/// system by calling RecyclePicture().
///
/// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
/// called on completion, and on success, to hold the picture descriptor.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Reset()
/// call is pending.
/// Returns PP_ERROR_INPROGRESS if there is another GetPicture() call pending.
/// Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
/// completes while GetPicture() is pending.
int32_t GetPicture(
const CompletionCallbackWithOutput<PP_VideoPicture>& callback);
/// Recycles a picture that the plugin has received from the decoder.
/// The plugin should call this as soon as it has finished using the texture
/// so the decoder can decode more pictures.
///
/// @param[in] picture A <code>PP_VideoPicture</code> to return to the
/// decoder.
void RecyclePicture(const PP_VideoPicture& picture);
/// Flushes the decoder. The plugin should call Flush() when it reaches the
/// end of its video stream in order to stop cleanly. The decoder will run any
/// pending Decode() call to completion. The plugin should make no further
/// calls to the decoder other than GetPicture() and RecyclePicture() until
/// the decoder signals completion by running |callback|. Just before
/// completion, any pending GetPicture() call will complete by running its
/// callback with result PP_ERROR_ABORTED to signal that no more pictures are
/// available. Any pictures held by the plugin remain valid during and after
/// the flush and should be recycled back to the decoder.
///
/// @param[in] callback A <code>CompletionCallback</code> to be called on
/// completion.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if the decoder isn't initialized.
int32_t Flush(const CompletionCallback& callback);
/// Resets the decoder as quickly as possible. The plugin can call Reset() to
/// skip to another position in the video stream. After Reset() returns, any
/// pending calls to Decode() and GetPicture()) abort, causing their callbacks
/// to run with PP_ERROR_ABORTED. The plugin should not make further calls to
/// the decoder other than RecyclePicture() until the decoder signals
/// completion by running |callback|. Any pictures held by the plugin remain
/// valid during and after the reset and should be recycled back to the
/// decoder.
///
/// @param[in] callback A <code>CompletionCallback</code> to be called on
/// completion.
///
/// @return An int32_t containing an error code from <code>pp_errors.h</code>.
/// Returns PP_ERROR_FAILED if the decoder isn't initialized.
int32_t Reset(const CompletionCallback& callback);
};
} // namespace pp
#endif // PPAPI_CPP_VIDEO_DECODER_H_
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