如何在PHP中处理上传视频并使用FFmpeg进行处理（绝对路径实践）

<?php
// 定义文件上传的目标目录，建议使用绝对路径，例如：
// 确保此目录存在且Web服务器用户拥有写入权限
$upload_dir = '/var/www/html/uploads/'; 

// 检查目录是否存在，不存在则尝试创建
if (!is_dir($upload_dir)) {
    mkdir($upload_dir, 0755, true);
}

$uploaded_video_path = '';
$uploaded_image_path = '';

// 处理视频文件上传
if (isset($_FILES['video']) && $_FILES['video']['error'] === UPLOAD_ERR_OK) {
    $video_name = basename($_FILES['video']['name']);
    $uploaded_video_path = $upload_dir . $video_name;
    if (move_uploaded_file($_FILES['video']['tmp_name'], $uploaded_video_path)) {
        echo "视频文件上传成功: " . $uploaded_video_path . "<br>";
    } else {
        echo "视频文件上传失败！<br>";
        // 可以在这里添加更详细的错误日志
    }
} else {
    echo "未选择视频文件或上传出错。<br>";
}

// 处理图片文件上传
if (isset($_FILES['image']) && $_FILES['image']['error'] === UPLOAD_ERR_OK) {
    $image_name = basename($_FILES['image']['name']);
    $uploaded_image_path = $upload_dir . $image_name;
    if (move_uploaded_file($_FILES['image']['tmp_name'], $uploaded_image_path)) {
        echo "图片文件上传成功: " . $uploaded_image_path . "<br>";
    } else {
        echo "图片文件上传失败！<br>";
    }
} else {
    echo "未选择图片文件或上传出错。<br>";
}

// 在此之后，您将拥有 $uploaded_video_path 和 $uploaded_image_path，它们是文件的绝对路径。
// 这些路径可以安全地传递给FFmpeg命令。
?>

<?php
// ... (接上一步的文件上传代码) ...

// 确保文件已成功上传并获取到绝对路径
if (!empty($uploaded_video_path) && !empty($uploaded_image_path)) {
    // 步骤1: 调整水印图片大小
    $output_image_resized_path = $upload_dir . "output_resized.jpeg"; // 输出到上传目录
    $command_resize_image = "ffmpeg -i " . escapeshellarg($uploaded_image_path) . " -s 128x128 " . escapeshellarg($output_image_resized_path);

    echo "执行命令: " . $command_resize_image . "<br>";
    shell_exec($command_resize_image);
    echo "水印图片已调整大小。<br>";

    // 步骤2: 将水印叠加到视频上
    $output_video_path = $upload_dir . "output_overlay.mp4"; // 最终输出视频到上传目录
    $command_overlay_video = "ffmpeg -i " . escapeshellarg($uploaded_video_path) . " -i " . escapeshellarg($output_image_resized_path);
    $command_overlay_video .= " -filter_complex \"[0:v][1:v] overlay=25:25\"";
    $command_overlay_video .= " -c:a copy " . escapeshellarg($output_video_path);

    echo "执行命令: " . $command_overlay_video . "<br>";
    system($command_overlay_video); // system() 可以直接输出FFmpeg的进度信息
    echo "水印已添加到视频。<br>";

    // 提示用户下载或显示处理结果
    echo "<p>处理完成，您可以在这里下载或查看结果：<a href='/uploads/output_overlay.mp4'>下载视频</a></p>";

    // 清理临时文件 (可选，根据业务需求决定是否立即清理)
    // unlink($uploaded_video_path);
    // unlink($uploaded_image_path);
    // unlink($output_image_resized_path);

} else {
    echo "文件路径无效，无法执行FFmpeg命令。<br>";
}

?>

<?php
// ... (文件上传代码，与步骤一相同) ...

if (!empty($uploaded_video_path) && !empty($uploaded_image_path)) {
    // 将上传文件的绝对路径存储到session或数据库，以便后续脚本访问
    session_start();
    $_SESSION['video_path'] = $uploaded_video_path;
    $_SESSION['image_path'] = $uploaded_image_path;

    // 重定向到处理脚本
    header("Location: process_video.php");
    exit();
} else {
    echo "文件上传失败，请重试。";
}
?>

<?php
session_start();

$video_path = $_SESSION['video_path'] ?? '';
$image_path = $_SESSION['image_path'] ?? '';

// 清理session变量，防止重复处理或信息泄露
unset($_SESSION['video_path']);
unset($_SESSION['image_path']);

if (!empty($video_path) && !empty($image_path)) {
    // 假设上传目录是 /var/www/html/uploads/
    $upload_dir = '/var/www/html/uploads/'; 

    // 步骤1: 调整水印图片大小
    $output_image_resized_path = $upload_dir . "output_resized_" . uniqid() . ".jpeg"; // 使用唯一ID避免冲突
    $command_resize_image = "ffmpeg -i " . escapeshellarg($image_path) . " -s 128x128 " . escapeshellarg($output_image_resized_path);
    shell_exec($command_resize_image);
    echo "水印图片已调整大小。<br>";

    // 步骤2: 将水印叠加到视频上
    $output_video_path = $upload_dir . "output_overlay_" . uniqid() . ".mp4"; 
    $command_overlay_video = "ffmpeg -i " . escapeshellarg($video_path) . " -i " . escapeshellarg($output_image_resized_path);
    $command_overlay_video .= " -filter_complex \"[0:v][1:v] overlay=25:25\"";
    $command_overlay_video .= " -c:a copy " . escapeshellarg($output_video_path);
    system($command_overlay_video);
    echo "水印已添加到视频。<br>";

    echo "<p>视频处理完成！您可以下载：<a href='/uploads/" . basename($output_video_path) . "'>下载视频</a></p>";

    // 清理原始上传文件和临时水印文件 (根据需求)
    unlink($video_path);
    unlink($image_path);
    unlink($output_image_resized_path);

} else {
    echo "无法获取文件信息，请重新上传。";
}
?>