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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.
#include <stdint.h>
#include <memory>
#include <string>
#include "base/files/file.h"
#include "base/files/memory_mapped_file.h"
#include "base/macros.h"
#include "base/threading/thread.h"
#include "base/threading/thread_checker.h"
#include "media/capture/video/video_capture_device.h"
namespace media {
class VideoFileParser;
// Implementation of a VideoCaptureDevice class that reads from a file. Used for
// testing the video capture pipeline when no real hardware is available. The
// supported file formats are YUV4MPEG2 (a.k.a. Y4M) and MJPEG/JPEG. YUV4MPEG2
// is a minimal container with a series of uncompressed video only frames, see
// the link for more
// information on the file format. Several restrictions and notes apply, see the
// implementation file.
// Example Y4M videos can be found in
// Example MJPEG videos can be found in media/data/test/bear.mjpeg.
// Restrictions: Y4M videos should have .y4m file extension and MJPEG videos
// should have .mjpeg file extension.
class CAPTURE_EXPORT FileVideoCaptureDevice : public VideoCaptureDevice {
// Reads and parses the header of a |file_path|, returning the collected
// pixel format in |video_format|. Returns true on file parsed successfully,
// or false.
// Restrictions: Only trivial Y4M per-frame headers and MJPEG are supported.
static bool GetVideoCaptureFormat(const base::FilePath& file_path,
media::VideoCaptureFormat* video_format);
// Constructor of the class, with a fully qualified file path as input, which
// represents the Y4M or MJPEG file to stream repeatedly.
explicit FileVideoCaptureDevice(const base::FilePath& file_path);
// VideoCaptureDevice implementation, class methods.
~FileVideoCaptureDevice() override;
void AllocateAndStart(
const VideoCaptureParams& params,
std::unique_ptr<VideoCaptureDevice::Client> client) override;
void StopAndDeAllocate() override;
// Opens a given file |file_path| for reading, and stores collected format
// information in |video_format|. Returns the parsed file to the
// caller, who is responsible for closing it.
static std::unique_ptr<VideoFileParser> GetVideoFileParser(
const base::FilePath& file_path,
media::VideoCaptureFormat* video_format);
// Called on the |capture_thread_|.
void OnAllocateAndStart(const VideoCaptureParams& params,
std::unique_ptr<Client> client);
void OnStopAndDeAllocate();
const uint8_t* GetNextFrame();
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_|.
std::unique_ptr<VideoCaptureDevice::Client> client_;
const base::FilePath file_path_;
std::unique_ptr<VideoFileParser> file_parser_;
VideoCaptureFormat capture_format_;
// Target time for the next frame.
base::TimeTicks next_frame_time_;
// The system time when we receive the first frame.
base::TimeTicks first_ref_time_;
} // namespace media