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// Copyright 2013 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_VIDEO_CAPTURE_FILE_VIDEO_CAPTURE_DEVICE_H_
#define MEDIA_VIDEO_CAPTURE_FILE_VIDEO_CAPTURE_DEVICE_H_
#include <string>
#include "base/files/file.h"
#include "base/memory/scoped_ptr.h"
#include "base/threading/thread.h"
#include "base/threading/thread_checker.h"
#include "media/video/capture/video_capture_device.h"
namespace media {
// Implementation of a VideoCaptureDevice class that reads from a file. Used for
// testing the video capture pipeline when no real hardware is available. The
// only supported file format is YUV4MPEG2 (a.k.a. Y4M), a minimal container
// with a series of uncompressed video only frames, see the link
// http://wiki.multimedia.cx/index.php?title=YUV4MPEG2 for more information
// on the file format. Several restrictions and notes apply, see the
// implementation file.
// Example videos can be found in http://media.xiph.org/video/derf.
class MEDIA_EXPORT FileVideoCaptureDevice : public VideoCaptureDevice {
public:
static int64 ParseFileAndExtractVideoFormat(
base::File* file,
media::VideoCaptureFormat* video_format);
static base::File OpenFileForRead(const base::FilePath& file_path);
// Constructor of the class, with a fully qualified file path as input, which
// represents the Y4M video file to stream repeatedly.
explicit FileVideoCaptureDevice(const base::FilePath& file_path);
// VideoCaptureDevice implementation, class methods.
~FileVideoCaptureDevice() override;
void AllocateAndStart(const VideoCaptureParams& params,
scoped_ptr<VideoCaptureDevice::Client> client) override;
void StopAndDeAllocate() override;
private:
// Returns size in bytes of an I420 frame, not including possible paddings,
// defined by |capture_format_|.
int CalculateFrameSize();
// Called on the |capture_thread_|.
void OnAllocateAndStart(const VideoCaptureParams& params,
scoped_ptr<Client> client);
void OnStopAndDeAllocate();
void OnCaptureTask();
// |thread_checker_| is used to check that destructor, AllocateAndStart() and
// StopAndDeAllocate() are called in the correct thread that owns the object.
base::ThreadChecker thread_checker_;
// |capture_thread_| is used for internal operations via posting tasks to it.
// It is active between OnAllocateAndStart() and OnStopAndDeAllocate().
base::Thread capture_thread_;
// The following members belong to |capture_thread_|.
scoped_ptr<VideoCaptureDevice::Client> client_;
const base::FilePath file_path_;
base::File file_;
scoped_ptr<uint8[]> video_frame_;
VideoCaptureFormat capture_format_;
int frame_size_;
int64 current_byte_index_;
int64 first_frame_byte_index_;
DISALLOW_COPY_AND_ASSIGN(FileVideoCaptureDevice);
};
} // namespace media
#endif // MEDIA_VIDEO_CAPTURE_FILE_VIDEO_CAPTURE_DEVICE_H_
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