溶解转场效果概述

溶解转场是一种平滑的视频过渡效果，通过逐渐混合两个视频帧来创建无缝的视觉过渡。本指南将详细介绍如何使用Xabe.FFmpeg在C#中实现多种溶解转场效果。

环境准备

NuGet 包安装

Bash
Install-Package Xabe.FFmpeg

引用命名空间

C#
using System;
using System.Threading.Tasks;
using Xabe.FFmpeg;

核心实现类

C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xabe.FFmpeg;

namespace App22
{
    /// <summary>
    /// 视频溶解转场处理器
    /// </summary>
    public class DissolveTransitionProcessor
    {
        /// <summary>
        /// 应用溶解转场效果
        /// </summary>
        /// <param name="inputVideo1">第一个输入视频路径</param>
        /// <param name="inputVideo2">第二个输入视频路径</param>
        /// <param name="outputPath">输出视频路径</param>
        /// <param name="transitionType">溶解类型</param>
        /// <param name="transitionDuration">转场持续时间（秒）</param>
        /// <returns>异步任务</returns>
        public async Task ApplyDissolveTransition(
            string inputVideo1,
            string inputVideo2,
            string outputPath,
            DissolveTransitionType transitionType = DissolveTransitionType.LinearDissolve,
            double transitionDuration = 2.0)
        {
            try
            {
                // 获取两个视频的媒体信息  
                var mediaInfo1 = await FFmpeg.GetMediaInfo(inputVideo1);
                var mediaInfo2 = await FFmpeg.GetMediaInfo(inputVideo2);

                // 计算转场开始的偏移量  
                double offset1 = mediaInfo1.Duration.TotalSeconds - transitionDuration;
                double offset2 = 0;

                // 构建复杂的滤镜图  
                string complexFilter = transitionType switch
                {
                    DissolveTransitionType.LinearDissolve =>
                        // 标准线性溶解  
                        "[0:v][1:v]xfade=" +
                        $"transition=dissolve:duration={transitionDuration}:" +
                        $"offset={offset1}[v];" +
                        "[0:a][1:a]acrossfade=" +
                        $"duration={transitionDuration}[a]",

                    DissolveTransitionType.SmoothDissolve =>
                        // 平滑溶解  
                        "[0:v][1:v]xfade=" +
                        $"transition=smoothleft:duration={transitionDuration}:" +
                        $"offset={offset1}[v];" +
                        "[0:a][1:a]acrossfade=" +
                        $"duration={transitionDuration}[a]",

                    DissolveTransitionType.ColorChannelDissolve =>
                        // 颜色通道混合溶解  
                        "[0:v]format=rgba[bg];" +
                        "[1:v]format=rgba[top];" +
                        "[bg][top]blend=" +
                        "all_mode=overlay:" +
                        $"all_opacity=0.5:" +
                        $"shortest=1[v];" +
                        "[0:a][1:a]acrossfade=" +
                        $"duration={transitionDuration}[a]",

                    _ => throw new ArgumentException("无效的溶解转场类型")
                };

                // 创建FFmpeg转换  
                var conversion = FFmpeg.Conversions.New()
                    .AddParameter($"-i \"{inputVideo1}\"")
                    .AddParameter($"-i \"{inputVideo2}\"")
                    .AddParameter("-filter_complex")
                    .AddParameter($"\"{complexFilter}\"")
                    .AddParameter("-map")
                    .AddParameter("[v]")
                    .AddParameter("-map")
                    .AddParameter("[a]")
                    .AddParameter("-c:v")
                    .AddParameter("libx264")
                    .AddParameter("-preset")
                    .AddParameter("medium")
                    .AddParameter("-crf")
                    .AddParameter("23")
                    .AddParameter("-c:a")
                    .AddParameter("aac")
                    .SetOutput(outputPath);

                // 执行转换  
                IConversionResult result = await conversion.Start();

                Console.WriteLine($"溶解转场处理完成：{transitionType} 效果");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"溶解转场处理错误: {ex.Message}");
                Console.WriteLine($"详细异常: {ex.StackTrace}");
                throw;
            }
        }
    }
}

使用示例

C#
using Xabe.FFmpeg;

namespace App22
{
    /// <summary>
    /// 视频溶解转场效果枚举
    /// </summary>
    public enum DissolveTransitionType
    {
        /// <summary>
        /// 标准线性溶解
        /// </summary>
        LinearDissolve,

        /// <summary>
        /// 柔和渐变溶解
        /// </summary>
        SmoothDissolve,

        /// <summary>
        /// 彩色通道混合溶解
        /// </summary>
        ColorChannelDissolve,

    }
    internal class Program
    {
        static async Task Main(string[] args)
        {
            // 设置FFmpeg路径（如果非标准安装）
            FFmpeg.SetExecutablesPath("D:\\Software\\ffmpeg-master-latest-win64-gpl-shared\\bin");

            var transitionProcessor = new DissolveTransitionProcessor();

            try
            {
               // 标准线性溶解
               await transitionProcessor.ApplyDissolveTransition(
                   @"D:\video\1.mp4",
                   @"D:\video\2.mp4",
                   @"D:\linear_dissolve.mp4",
                   DissolveTransitionType.LinearDissolve,
                   transitionDuration: 2.5
               );

                // 柔和渐变溶解
                await transitionProcessor.ApplyDissolveTransition(
                    @"D:\video\1.mp4",
                    @"D:\video\2.mp4",
                    @"D:\smooth_dissolve.mp4",
                    DissolveTransitionType.SmoothDissolve,
                    transitionDuration: 3.0
                );

                // 颜色通道混合溶解
                await transitionProcessor.ApplyDissolveTransition(
                    @"D:\video\1.mp4",
                    @"D:\video\2.mp4",
                    @"D:\color_dissolve.mp4",
                    DissolveTransitionType.ColorChannelDissolve,
                    transitionDuration: 2.0
                );
            }
            catch (Exception ex)
            {
                Console.WriteLine($"处理失败: {ex.Message}");
            }
        }
    }
}

结语

Xabe.FFmpeg 提供了强大的视频处理能力，通过精心设计的滤镜和参数，可以创造出丰富多彩的视频转场效果。

希望这个详细的指南能帮助你深入理解如何使用 Xabe.FFmpeg 实现视频溶解转场效果！