QVideoPlayer

Introduction

QVideoPlayer is a video player based on Qt and SDL, utilizing FFmpeg for media processing. It combines the powerful interface capabilities of Qt with the audio processing efficiency of SDL, offering a smooth video playback experience.

Core Features

• Video Playback: Decodes video streams using the FFmpeg library, supporting various video formats.
• Audio Playback: Integrates with the SDL library for audio playback, providing synchronized audio and video experience.
• User Interface: Built on the Qt framework, offering graphical user interface interactions.
• Media Control: Includes basic media playback controls such as play, pause, and stop.

Technical Details

FFmpeg Principles

FFmpeg is a multimedia framework used for processing audio and video data. In QVideoPlayer, FFmpeg is utilized to decode video files and extract audio and video streams.

• Video Decoding: Through the avcodec_send_packet and avcodec_receive_frame functions, FFmpeg decodes video packets into frames.
• Audio Decoding: Similarly, audio streams are decoded via FFmpeg, converting audio packets into playable frames.

SDL Audio Processing

SDL (Simple DirectMedia Layer) is a cross-platform development library used for handling audio, keyboard, mouse, and other devices. In this project, SDL is used to handle audio output.

• Audio Callback: Initializes the audio device using SDL_OpenAudio function and sets up a callback function, triggered when the audio device requires more data.

Qt Framework

Qt is a cross-platform C++ application framework for developing applications with graphical user interfaces. QVideoPlayer uses Qt to build and manage the user interface.

• Event Handling: Qt's event system is used for handling user input, such as key press events.

Multithreading and Synchronization

The project employs multithreading to separate video decoding and playback logic, enhancing performance and responsiveness.

• Video and Audio Queues: Uses BlockingQueue to store decoded audio and video frames, ensuring thread-safe data access.

Compilation and Running

Ensure your system has Qt 6, SDL 2, FFmpeg, and Boost C++ Libraries installed.

Compilation Steps

1. Clone the repository:

   git clone https://github.com/nagisa77/QVideoPlayer
   

2. Enter the project directory:

   cd QVideoPlayer
   

3. Create and enter the build directory:

   mkdir build && cd build
   

4. Generate Makefile using CMake:

   cmake ..
   

5. Compile the project:

   make
   

Running

In the build directory, run the compiled executable file, passing the path to the video file as an argument:

./QVideoPlayer path_to_video_file

Developer's Guide

Project Structure

• main.c: Program entry point, setting up the Qt application and player view.
• video_codec.hpp/cpp: Handles the logic of video and audio codec processing.
• video_player_view.hpp/cpp: Qt view class, responsible for rendering video frames and handling user inputs.
• blocking_queue.h: A thread-safe queue for storing decoded frames.